Konsep Dasar Agroekosistem | Nitrogen | Plants
Konsep Dasar Agroekosistem - Free download as Word Doc (.doc), PDF File (.pdf), Text File (.txt) or read online for free...
KONSEP DASAR AGROEKOSISTEM Bahan kajian MK. Manajemen Agroekosistem FPUB Maret 2010 Diabstraksikan oleh Prof Dr Ir Soemarno MS Dosen Jur Tanah FPUB
Konsep Ekosistem Suatu EKOSISTEM merupakab lingkungan biologis yang terdiri atas semua organisme hidup dalam suatu area tertentu, serta komponen abiotik dan komponen fisik dari lingkungan yang berinteraksi dengan organisme, seperti udara, tanah, air dan radiasi matahari. Ekosistem ini meliputi semua organisme dalam suatu area tertentu, berinteraksi dengan faktor-faktor abiotik ; merupakan suatu komunitas biologis dengan lingkungan fisiknya. Ecosystem: Complex of living organisms, their physical environment, and all their interrelationships in a particular unit of space. An ecosystem's abiotic (nonbiological) constituents include minerals, climate, soil, water, sunlight, and all other nonliving elements; its biotic constituents consist of all its living members. Two major forces link these constituents: the flow of energy and the cycling of nutrients. The fundamental source of energy in almost all ecosystems is radiant energy from the sun; energy and organic matter are passed along an ecosystem's food chain. The study of ecosystems became increasingly sophisticated in the later 20th century; it is now instrumental in assessing and controlling the environmental effects of agricultural development and industrialization. (http://www.answers.com/topic/ecosystems-1#ixzz1f2hC3okb) Definisi Ekosistem Sistem ekologi dapat didefinisikan sebagai suatu komunitas tumbuhan dan binatang yang saling berinteraksi beserta lingkungan abiotik atau alamiahnya. Ekosistem-ekosistem dapat dikelompokkan berdasarkan vegetasi dominannya, topography, iklim atau beberapa criteria lainnya. Boreal forests, for example, are characterized by the predominance of coniferous trees; prairies are characterized by the predominance of grasses; the Arctic tundra is determined partly by the harsh climatic zone. In most areas of the world, the human community is an important and often dominant component of the ecosystem. Ecosystems include not only natural areas (e.g., forests, lakes, marine coastal systems) but also human-constructed systems (e.g., urban ecosystems, agroecosystems, impoundments). Human populations are increasingly concentrated in urban ecosystems, and it is estimated that, by the year 2010, 50 percent of the world's population will be living in urban areas. Suatu bentang-lahan terdiri atas mozaik ekosistem-ekosistem, termasuk kotakota, sungai, danau, system pertanian, dsb. Batas-batas yang tepat di antara ekosistem-ekosistem tersebut seringkali sulit ditetapkan.
A functional system that includes an ecological community of organisms together with the physical environment, interacting as a unit. Ecosystems are characterized by flow of energy through food webs, production and degradation of organic matter, and transformation and cycling of nutrient elements. This production of organic molecules serves as the energy base for all biological activity within ecosystems. The consumption of plants by herbivores (organisms that consume living plants or algae) and detritivores (organisms that consume dead organic matter) serves to transfer energy stored in photosynthetically produced organic molecules to other organisms. Coupled to the production of organic matter and flow of energy is the cycling of elements. All biological activity within ecosystems is supported by the production of organic matter by autotrophs (organisms that can produce organic molecules such as glucose from inorganic carbon dioxide; see illustration). More than 99% of autotrophic production on Earth is through photosynthesis by plants, algae, and certain types of bacteria. Collectively these organisms are termed photoautotrophs (autotrophs that use energy from light to produce organic molecules). In addition to photosynthesis, some production is conducted by chemoautotrophic bacteria (autotrophs that use energy stored in the chemical bonds of inorganic molecules such as hydrogen sulfide to produce organic molecules). The organic molecules produced by autotrophs are used to support the organism's metabolism and reproduction, and to build new tissue. This new tissue is consumed by herbivores or detritivores, which in turn are ultimately consumed by predators or other detritivores.
Model aliran energy melalui ekosistem. http://www.answers.com/topic/ecosystems-1#ixzz1f2eXwrp3 Ekosistem darat (terrestrial ecosystems), yang meliputi 30% permukaan bumi, menyumbangkan sekitar separuh dari total produksi global bahan organic fotosintetik— sekitar 60 × 1015 gram karbon per tahun. Lautan, yang meliputi 70% permukaan bumi menghasilkan bahan organic sekitar 51 × 1015 g C setiap tahun. Jaring-jaring Makanan
Organisme dapat diklasifikasikan berdasarkan banyaknya transfer energy melalui ajring-jaring makanan. Produksi bahan organic secara foto-autotrofik mencerminkan transfer energy yang pertama di dalam suatu ekosistem dan diklasifikasikan denagai PRODUKSI PRIMER. Konsumsi suatu tumbuhan oleh by a herbivora merupakan transfer energi ke dua , sehingga herbivore menempati tingkat trofik ke dua, juga dikenal sebagai PRODUKSI SEKUNDER. Organiske konsumen yang merupakan transfer ke satu, dua atau tiga dari foto-autotrof dikelompokkan sebagai konsumen primer, sekunder, dan tersier. Bergerak melalui suatu jarring-jaring makanan, energy hilang selama proses transfer sebagai panas, sebagaimana dijelaskan dengan Hukum Termodinamika ke dua. Oleh karena itu, jumlah total transfer energy jarang yang melebihi empat atau lima; dengan adanya kehilangan energy selama setiap proses transfer, maka sedikit sekali energy yang tersedia untuk mendukung organism yang berada pada tingkat tertinggi dari suatu jaring-jaring makanan. Energy flow drives the ecosystem, determining limits of the food supply and the production of all biological resources. Light energy from the sun is captured by green plants and converted to chemical energy. Energy is stored in plants as carbohydrates and used by the plant to support all functions such as vegetative growth, fruit maturation and respiration. Other organisms use and convert this chemical energy to various forms through food chains. A food chain is a succession of organisms in a community that constitutes a feeding sequence in which food energy is transferred from one organism to the next as each consumes a lower number and in turn is preyed upon by a higher number. At the bottom of the chain is a photosynthesizing plant, usually followed by an herbivore, a successions of carnivores, and finally decomposers. At each step, some of the chemical energy is assimilated and used by the organism and the rest is released in respiration and waste products. Jaring-jaring makanan (Food web) merupakan rantai-rantai makanan yang saling berkaitan secara “rumit” dalam suatu komunitas. Struktur trofik (Trophic structure) merupakan serangkaian keterkaitan dalam suatu jaring-jaring makanan yang mendeskripsikan transfer energy dari suatu tingkat nutritional ke tingkat berikutnya. Sasaran produksi tanaman adalah memaksimumkan energy ekosistem ke dalam hasilpanen; penggunaan energy tanaman oleh hama tidak diperlukan karena hal ini berarti mengambil energy dari produksi tanaman.
Dalam suatu siklus biogeokimia, unsure-unsur hara anorganik yang diperlukan untuk pertumbuhan dan perkembangan organism bersirkulasi dari komponen abiotik ke komponen biotic dan kembali lagi ke komponen abiotik dari ekosistem (Source Flint, M.L and P. Gouveia, 2001) Sumber: http://www.knowledgebank.irri.org/ipm/index.php/ecosystemecology….. diunduh 29/6/2011
Diagram jaring-jaring makanan dalam alfalfa. Setiap tanda panah mencerminkan transfer makanan, atau energy dari satu organism ke organism lainnya. Jaring-jaring menjadi lebih kompleks kalau semakin banyak spesies yang dimasukkan ke dalam system. (Flint, M.L. and P. Gouveia. 2001). Sumber: http://www.knowledgebank.irri.org/ipm/index.php/ecosystemecology….. diunduh 29/6/2011
Organisme hidup membentuk jaring-jaring makanan The living organisms in an agro-ecosystem are the biotic component. The organisms can be analyzed as a food web that represents the transfer of material and energy from one group of organisms to another. For a food web analysis, organisms are grouped by their function in the flow of energy and nutrients rather than by their classification into genus and species. All the plants in an agro-ecosystem make up the primary producers and provide the basis of the food web. Plants capture solar energy through their leaves and in combination with water and nutrients from the soil and carbon dioxide from the air generate plant material. The next level of organisms is the herbivores that live off the nutrients and energy provided by plants or primary producers. Many different types of organisms can be herbivores - birds, insects, nematodes, fungi, bacteria and virus. In turn, the energy and nutrients in herbivores are exploited for growth and reproduction by another group of organisms called secondary consumers. Animals that live off the energy and nutrients in the substance of secondary consumers are called tertiary consumers. Many different types of organisms can also be primary, secondary and tertiary consumers.
Sumber: http://www.knowledgebank.irri.org/ipm/index.php/ecosystem-ecology….. diunduh 29/6/2011
Sumber: http://platforms.inibap.org/agro/concepts.html ….. diunduh 29/6/2011 The soil food web has many organisms feeding both on living and dead plant material. Thus, the many organisms derive energy to grow and reproduce and eventually nutrients tied up in plant and animal material is available again for plant growth.
Sumber: http://platforms.inibap.org/agro/concepts.html ….. diunduh 29/6/2011
Siklus Biogeokimia In contrast to energy, which is lost from ecosystems as heat, chemical elements (or nutrients) that compose molecules within organisms are not altered and may repeatedly cycle between organisms and their environment. Approximately 40 elements compose the bodies of organisms, with carbon, oxygen, hydrogen, nitrogen, and phosphorus being the most abundant. If one of these elements is in short supply in the environment, the growth of organisms can be limited, even if sufficient energy is available. In particular, nitrogen and phosphorus are the elements most commonly limiting organism growth. This limitation is illustrated by the widespread use of fertilizers, which are applied to agricultural fields to alleviate nutrient limitation.
The movement of energy from one level of the food web to the next. The proportion of energy at one level of the food web that makes it to the next level is called ecological efficiency - this is usually less than 10%. In an agroecosystem, we also care about how well the energy consumed by organisms, usually either the crop plants (the producers, with energy from the sun) or livestock (herbivores, with energy from feed or pasture), is converted into body tissue - this is conversion efficiency.
Sumber: http://www.acad.carleton.edu/curricular/BIOL/classes/bio160/ClassResources/Case_Studies/Case 3_Energy/Case3_Directions.htm ….. diunduh 29/6/2011 Carbon cycles between the atmosphere and terrestrial and oceanic ecosystems. This cycling results, in part, from primary production and decomposition of organic matter. Rates of primary production and decomposition, in turn, are regulated by the supply of nitrogen, phosphorus, and iron. The combustion of fossil fuels is a recent change in the global cycle that releases carbon that has long been buried within the Earth's crust to the atmosphere. Carbon dioxide in the atmosphere traps heat on the Earth's surface and is a major factor regulating the climate. This alteration of the global carbon cycle along with the resulting impact on the climate is a major issue under investigation by ecosystem ecologists.
Siklus Karbon Organic chemicals are made from carbon more than any other atom, so the Carbon Cycle is a very important one. Carbon between the biological to the physical environment as it moves through the carbon cycle. Earth's atmosphere contains 0.035% carbon dioxide, CO2, and the biological environment depends upon plants to pull carbon into sugars, proteins, and fats. Using photosynthesis, plants use sunlight to bind carbon to glucose, releasing oxygen (O2)in the process. Through other metabolic processes, plants may convert glucose to other sugars, proteins, or fats. Animals obtain their carbon by eating and digesting plants, so carbon moves through the biotic environment through the trophic system. Herbivore eat plants, but are themselves eaten by carnivores. Carbon returns to the physical environment in a number of ways. Both plants and animals respire, so they release CO2 during respiration. Luckily for animals, plants just happen to consume more CO2 through photosynthesis than they can produce. Another route of CO2 back to the physical environment occurs through the death of plants and animals. When organisms die, decomposers consume their bodies. In the process, some of the carbon returns to the physical environment by way of fossilization. Some of it remains in the biological environment as other organisms eat the decomposers. But by far, most of the carbon returns to the physical environment through the respiration of CO2.
Sumber: http://www.starsandseas.com/SAS%20Ecology/SAS %20chemcycles/cycle_carbon.htm ..... diunduh 29/6/2011
Siklus Nitrogen Proteins, nucleic acids, and other organic chemicals contain nitrogen, so nitrogen is a very important atom in biological organisms. Nitrogen makes up 79% of Earth's atmosphere, but most organisms can not use nitrogen gas (N2). N2 enters the trophic system through a process called nitrogen fixation. Bacteria found on the roots of some plants can fix N2 to organic molecules, making proteins. Again, animals get their nitrogen by eating plants. But after this point, the nitrogen cycle gets far more complicated than the carbon cycle. Animals releases nitrogen in their urine. Fish releases NH3, but NH3 when concentrated, is poisonous to living organisms. So organisms must dilute NH3 with a lot of water. Living in water, fish have no problem with this requirements, but terrestrial animals have problems. They convert NH3 into urine, or another chemical that is not as poisonous as NH3. The process of releases NH3 is called ammonification. Because NH3 is poisonous, most of the NH3 which is released is untouchable. But soil bacteria have the ability to assimilate NH3 into proteins. These bacteria effectively eats the NH3, and make proteins from it. This process is called assimilation. Some soil bacteria does not convert NH3 into proteins, but they make nitrate NO3instead. This process is called nitrification. Some plants can use NO3-, consuming nitrate and making proteins. Some soil bacteria, however, takes NO3-, and converts it into N2, returning nitrogen gas back into the atmosphere. This last process is called denitrification, because it breaks nitrate apart.
Sumber: http://www.starsandseas.com/SAS%20Ecology/SAS %20chemcycles/cycle_carbon.htm ..... diunduh 29/6/2011
Siklus Phosphorus Phosphorus is the key to energy in living organisms, for it is phosphorus that moves energy from ATP to another molecule, driving an enzymatic reaction, or cellular transport. Phosphorus is also the glue that holds DNA together, binding deoxyribose sugars together, forming the backbone of the DNA molecule. Phosphorus does the same job in RNA. Again, the keystone of getting phosphorus into trophic systems are plants. Plants absorb phosphorous from water and soil into their tissues, tying them to organic molecules. Once taken up by plants, phosphorus is available for animals when they consume the plants. When plants and animals die, bacteria decomposes their bodies, releasing some of the phosphorus back into the soil. Once in the soil, phosphorous can be moved 100s to 1,000s of miles from were they were released by riding through streams and rivers. So the water cycle plays a key role of moving phosphorus from ecosystem to ecosystem. In some cases, phosphorous will travel to a lake, and settle on the bottom. There, it may turn into sedimentary rocks, limestone, to be released millions of years later. So sedimentary rocks acts like a back, conserving much of the phosphorus for future econs.
Sumber: http://www.starsandseas.com/SAS%20Ecology/SAS %20chemcycles/cycle_carbon.htm ..... diunduh 29/6/2011
Siklus hara dalam suatu agroekosistem melibatkan tanaman, ikan dan ternak. Salah satu jalur utama aliran hara adalah jalur tanaman-ternak-tanah. KOlam ikan, jalur utamanya adalah tanaman dan ternak. Dalam beberapa kasus dalam system pertanian tradisional di Asia,, limbah manusia dan rumahtangga menjadi input penting bagi tanaman dan kolam ikan, sedangkan limbah dapur penting bagi ternak dan kolam ikan.
Sumber: Edwards (1993) (http://www.fao.org/docrep/006/y5098e/y5098e05.htm ..... diunduh 2/7/2011)
Aliran hara di antara komponebn dalam agroekosistem dan antara agroekosistem dengan system eksternalnya adalah sebagai berikut.
Sumber: Le and Rambo (1993) (http://www.fao.org/docrep/006/y5098e/y5098e05.htm ..... diunduh 2/7/2011)
Fotosintesis Organisme dan fungsi suatu sel hidup bergantung pada persediaan energi yang tak henti-hentinya, sumber energi ini tersimpan dalam molekul-molekul organik seperti karbohidrat. Organisme heterotrofik seperti ragi dan kita sendiri, hidup dan tumbuh dengan memasukkan molekul-molekul organik ke dalam sel-selnya. Untuk tujuan praktis, satu-satunya sumber molekul bahan bakar yang menjadi tempat bergantung seluruh kehidupan ialah fotosintesis. Fotosintesis menyediakan makanan bagi hampir seluruh kehidupan di dunia baik secara langsung atau tidak langsung. Organisme memperoleh senyawa organik yang digunakan untuk dan rangka karbon dengan satu atau dua cara utama: nutrisi autotrofik atau heterotrofik. Autotro dapat diartikan bahwa dapat menyediakan makanan bagi diri sendiri hanya dalam pengertian bahwa autotrof dapat mempertahankan dirinya sendiri tanpa memakan dan menguraikan organisme lain. Autotrof membuat molekul organik mereka sendiri dari bahan mentah anorganik yang diperoleh dari lingkuannya. Oleh karena alasan inilah, para ahli biologi menyebut autotrof sebagai produsen biosfer. Organisme heterotrof memperoleh materi organik melalui cara pemenuhan nutrisi kedua. Ketidakmampuan dalam membuat makanan mereka sendiri, menyebabkan hererotrof ini hidup tergantung pada senyawa yang dihasilkan oleh organisme lain; heteritrif merupakan komponen biosfer. Sebagian autotrof mengkonsumsi sisa-sisa organisme mati, menguraikan dan memekan sampah seperti bangkai, tinja dan daun-daun yang gugur. Heterotrof ini dikenak sebagai pengurai. Sebagian besar fungi dan banyak jenis bakteri memperoleh makana dengan cara seperti ini. Hampir seluruh heterotrof, termrasuk manusia, benar-benar tergantung pada fotoautotrof untuk mrndapatkan makanan dan juga untuk mendapatkan oksigen, yang merupakan produk samping fotosintesis. Jalur Fotosintesis Dengan keberadaan cahaya, bagian-bagian tumbuhan yang berwarna hijau menghasilkan bahan organik dan oksigen dari karbon dioksida dan air. Dengan menggunakan rumus molekul, persamaan kimia fotosintesis adalah: 6CO2 + 12 H2O + energi cahaya -----> C6H12O6 + 6O2 + 6H2O Karbohidrat C6H12O6 ialah glukosa. Air muncul pada kedua sisi persamaan itu karena 12 molekul dikonsumsi dan 6 molekul terbentuk lagi selama fotosintesis. Persamaan itu dapat disederhanakan dengan memperlihatkan selisih konsumsi air: 6CO2 + 6H2O + energi cahaya ----> C6H12O6 + 6O2 Dalam bakteri berfotosintesis, sebagai pengganti H2O dipakai zat pereduksi yang lebih kuat seperti H2, H2S dan H2R (R adalah gugus organik). Persamaan reaksinya adalah: 2CO2 + 2H2R -----> 2C2O + O2 +2R Bakteri menggunakan H2R dan menggunakan hidrogen untuk membuat gula. Dari reaksi kimia tersebut dapat dikatakan bahwa semua organisme fotosintetik membutuhkan sumber hidrogen, tetapi sumber itu bermacam-macam.
Tempat Berlangsungnya Proses Fotosintesis Di dalam tumbuhan, proses fotosintesis pada umumnya berlangsung dalam organel khusus yang disebut plastid. Plastid mengandung senyawa, yaitu klorofil. Semua bagian yang berwarna hijau pada tumbuhan, termasuk batang hijau dan buah yang belum matang, memiliki kloroplas, tetapi daun merupakan tempat utama berlangsungnya fotosintesis pada sebagian besar tumbuhan. Terdapat ± setengah juta kloroplas tiap milimeter persegi permukaan daun. Warna daun berasal dari klorofil, pigmen warna hijau yang terdapat dalam kloroplas. Energi cahaya yang diserap klorofil inilah yang menggunakan sintesis molekul makanan dalam kloroplas. Sebagian besar spesies tumbuhan, terpacu pertumbuhan dan perkecambahan dalam keadaan terang. Namun biji juga dapat terhambat perkecambahanyya oleh cahaya. Panjang gelombang merah jauh dari sinar matahari hampir selalu merupakan panjang gelombang yang paling menghambat. Cahaya biru juga kadang menghambat. Biji yang membutuhkan cahaya untuk berkecambah disebut fotodorman. Biji yang biasanya berkecambah dalam gelap akan terhambat oleh cahaya. Biji yang biasa berkecambah dalam gelap akan mengalami dormansi atau fase istirahat saat terkena cahaya dalam tingkat intensitas tertentu. Cahaya tampak sebagai sumber energi yang digunakan tumbuhan untuk fotosintesis merupakan bagian spektrum energi radiasi. Reaksi cahaya dalam fotosintesis merupakan bagian akibat langsung penyerapan foton oleh molekul pigmen seperti klorofil. Tidak seluruh foton mempunyai tingkat energi yang cocok untuk menggiatkan pigmen daun. Di atas 760 nm foton tidak memiliki cukup energi dan di bawah 390 nm foton memiliki terlalu banyak energi, menyebabkan ionisasi dan kerusakan pigmen. Hanya foton dengan panjang gelombang antara 390 dan 760 nm memiliki tingkat energi yang cocok untuk fotosintesis. Karena penggiatan pigmen merupakan akibat langsung interaksi antara foton dan pigmen, pengukuran cahaya yang digunakan dalam fotosintesis seringkali berdasarkan densitas aliran foton, dan bukan berdasarkan energi. Densitas aliran foton ialah jumlah foton yang menumbuk suatu luas permukaan tertentu per satuan waktu. Karena panjang gelombang antara 400 dan 700 nm itu paling efisien digunakan dalam fotosintesis, pengukuran cahaya untuk fotosintesis biasanya didasarkan pada densitas aliran foton dalam panjang gelombang 400 dan 700 nm tersebut (Michael,1994).
http://ecology07.blogspot.com/2011_03_01_archive.html …. Diunduh 29/6/2011
Kesehatan Ekosistem It is important to recognize the inherent difficulties in defining "health," whether at the level of the individual, population, or ecosystem. The concept of health is somewhat of an enigma, being easier to define in its absence (sickness) than in its presence. Perhaps partially for that reason, ecologists have resisted applying the notion of "health" to ecosystems. Yet, ecosystems can become dysfunctional, particularly under chronic stress from human activity. For example, the discharge of nutrients from sewage, industrial waste, or agricultural runoff into lakes or rivers affects the normal functioning of the ecosystem, and can result in severe impairment. Excessive nutrient inputs from human activity was one of the major factors that severely compromised the health of the lower Laurentian Great Lakes (Lake Erie and Lake Ontario) and regions of the upper Great Lakes (Lake Michigan). Unfortunately, degraded ecosystems are becoming more the rule than the exception. The study of the features of degraded systems, and comparisons with systems that have not been altered by human activity, makes it possible to identify the characteristics of healthy ecosystems. Healthy ecosystems may be characterized not only by the absence of signs of pathology, but also by signs of health, including measures of vigor (productivity), organization, and resilience. Vigor can be assessed in terms of the metabolism (activity and productivity) of the system. Ecosystems differ greatly in their normal ranges of productivity. Estuaries are far more productive than open oceans, and marshes have higher productivity than deserts. Health is not evaluated by applying one standard to all systems. Organization
can be assessed by the structure of the biotic community that forms an ecosystem and by the nature of the interactions between the species (both plants and animals). Invariably, healthy ecosystems have more diversity of biota than ecologically compromised systems. Resilience is the capacity of an ecosystem to maintain its structure and functions in the face of natural disturbances. Systems with a history of chronic stress are less likely to recover from normal perturbations such as drought than those systems that have been relatively less stressed. Healthy ecosystems can also be characterized in economic, social, and human health terms. Healthy ecosystems support a certain level of economic activity. This is not to say that the ecosystem is necessarily self-sufficient, but rather that it supports economic productivity to enable the human community to meet reasonable needs. Inevitably, ecosystem degradation impinges on the long-term sustainability of the human economy that is associated with it, although in the short-term this may not be evident, as natural capital (e.g., soils, renewable resources) may be overexploited and temporarily enhance economic returns. Similarly, with respect to social well-being, healthy ecosystems provide a basis for and encourage community integration. Historically, for example, native Hawaiian groups managed their ecosystem through a well-developed social cohesiveness that provided a high degree of cooperation in fishing and farming activity. Kesehatan Agro-ecosystem One of the basic hypotheses in the research proposal is that the agro-ecosystem health paradigm will provide a superior conceptual framework than agricultural sustainability, which has remained 'without much empirical content because of the lack of a comprehensive definition and analytical methodology' (ILRI 1998). Of course, it is possible to distinguish between the two concepts, but for the practical purposes of this research proposal they are fundamentally similar, essentially synonymous (this comparison is developed in more detail in Smit and Smithers (1994). Once the term 'agro' is appended to 'ecosystem' we have explicitly included human components, such that 'agro-ecosystem' is fundamentally equivalent to a broad definition of 'agriculture', which includes ecological and human components. “Sustainable agriculture” telah didefinisikan dengan berbagai cara dan sudut pandang (Smit and Brklacich 1989; Cai and Smit 1994; Smit and Smithers 1994), tetapi kebanyakan melingkupi sifat-sifat esensial yang sama. Misalnya dua definisi berikut ini: Agri-food systems that are economically viable, meet society's need for safe and nutritious foods, while conserving natural resources and the quality of the environment for future generations (SCC 1992), Agricultural system that can indefinitely meet demands for food and fibre at socially acceptable economic and environmental costs (Crosson 1992). Dalam kedua hal tersebut di atas, pertanian berkelanjutan didefinisikan dengan memperhatikan: • Kebutuhan atau permintaan social atas pangan, termasuk gizi, dan mencerminkan kesehatan manusia • Kelayakan ekonomis, mengacu kepada pemeliharaan system produksi • Kualitas lingkungan, yang diarahkan pada kondisi sumberdaya biofisik.
Definisi “keberlanjutan” juga memperhatikan sifat-sifat ini atas waktu ('generasi mendatang” atau 'indefinite'). Definisi kesehatan agro-ecosystem melingkupi sifat-sifat esensial yang sama, yaitu: 1. Kesejahteraan manusia 2. Keragaan ekonomis, dan 3. Kondisi ekologis. Pada kenyataannya, esensi dari perspektif kesehatan agroekosistem (agroecosystem health, AESH) adalah bahwa ia mencerminkan eksistensi dan interrelationships di antara beberapa domain system pertanian (economi, manusia dan ekologi), dan bahwa kesehatan system secara keseluruhan merupakan fungsi dari kondisi dan interdependensi di antara komponen-komponen ini. A simple conceptualisation of agro-ecosystem health indicates three main dimensions, which interact (hence overlapping sets), which manifest at different scales (hence the different sizes of sets), and which can be employed in numerous applications, including a) using indicators to compare systems or document changes in AESH, b) identifying and specifying relationships among dimensions to understand dynamics and determinants of AESH, and c) assessing responses in AESH to stresses, both those associated with external environments (such as climatic variations or macroeconomic conditions) and those reflecting interventions or policies.
Kesehatan Agro-ecosystem: Suatu teladan representasi diagramatik. Landasan konseptual dari dua paradigm ini, AESH dan agricultural sustainability (AS), pada hakekatnya sinonim. Keduanya bersifat evaluative dari keseluruhan kondisi lingkungan pedesaan, ekonomi, dan manusia. Sehingga sasarannya juga meliputi komponen ini: • Peningkatan ketahanan pangan
Pengentasan kemiskinan Melestarikan kualitas lingkungan yang baik.
In other respects as well, AESH and AS are very similar. Both are applicable at different spatial and temporal scales. For both, considerable effort has been expended in developing indicators, and similar kinds of indicators (often very long lists) have been proposed. Indicators can take a wide variety of forms, including state and functional indicators, diagnostic and early warning indicators. There are also many examples of particular empirical studies employing indicators, especially of sustainable agriculture . However, neither of these frameworks can supply a single, comprehensive measurable indicator which can adequately capture the scope of these systems. Nor do either of them provide a specific set of analytical steps to document change, assess responses, or evaluate interventions in these systems. The noteworthy contribution of the agroecosystem health concept is a metaphor, providing a broad framework which facilitates the consideration of multiple dimensions and the interactions among them. Indikator kesehatan agro-ecosystem What is the route by which a metaphor or concept can be applied to something so that researchers or practitioners can use in the field? For example, there is the interest in indicators, or measurable properties which indicate the health of an agroecosystem. For indicators, which represent only one element of any analysis, three distinct approaches have been tried. Holistik This approach, of which several versions have been proposed, aims to define a set of very generic 'criteria', essentially from first principles, which will be applicable to all dimensions. Thus, we get such 'holistic indicators' as integrity, efficiency, resilience, effectiveness, response capability, balance, richness, transformation ability, selfregulatory capacity, flexibility, stability, and so on. A particular appeal of this approach is the expectation that the selected criteria will lead to measurable equivalent indicators on each of the dimensions.
A conceptual framework for agro-ecosystem health. Sumber: http://www.ilri.org/InfoServ/Webpub/fulldocs/Aesh/Concepts.htm ..... diunduh 29/6/2011 Terintegrasi = Disaggregated In this approach, the indicators of the various dimensions of agro-ecosystem health are supplied by scientists and practitioners in each of the disciplines involved. Indicators developed via this route tend to reflect the variables which are conventionally analysed in the various disciplines. Thus, economists provide indicators such as gross margins, benefit /cost ratios, or net income. Sociologists will list measures of household and community structure, power relations, equity, gender roles, and so on. From the human health and nutrition fields come indicators of morbidity, longevity, other physiological features and measures of nutritional status or functionality. From the geophysical and biological sciences come equally long lists of ecosystem variables which have been of theoretical interest or have been used before. This approach certainly generates an ample smorgasbord of indicators. The weaknesses of this approach are that the lists are impractically long, there are no established principles for selecting from among the many possibilities (they may all be 'scientifically valid'), and they often are not readily understood by the people in the agro-ecosystems. Berbasis Komunitas = Community-based The essence of this approach (also called stakeholder-derived) is that the indicators are identified with the active participation of the people who live in the agroecosystem. A variety of methods are available for this kind of participatory approach, in which the researchers necessarily play at least a facilitatory role, but where the indicators are certainly meaningful to local people as well as to the analysts. These include a practical and efficient way of selecting key indicators, allowing researchers to learn about communities' priorities and alternative measurements (sometimes supplied
directly by residents), and promotion of people's involvement in (and 'ownership of') both analysis of agro-ecosystems and any management initiatives to improve their health.
Bagaimana Ekosistem Sehat menjadi Patologis Stress from human activity is a major factor in transforming healthy ecosystems to sick ecosystems. Chronic stress from human activity differs from natural disturbances. Natural disturbances (fires, floods, periodic insect infestations) are part of the dynamics of most ecosystems. These processes help to "reset" ecosystems by recycling nutrients and clearing space for recolonization by biota that may be better adapted to changing environments. Thus, natural perturbations help keep ecosystems healthy. In contrast, chronic and acute stress on ecosystems resulting from human activity (e.g., construction of large dams, release of nutrients and toxic substances into the air, water, and land) generally results in long-term ecological dysfunction. Lima sumber utama cekaman (stress) antropogenik (akibat dari kegiatan manusia) terhadap ekosistem, yaitu: rekayasa struktur fisik, panen berlebihan, limbah residual, masuknya spesies eksotik, dan perubahan global. Rekayasa Struktur Fisik Aktivitas-aktivitas seperti drainage rawa-rawa, pengerukan dasar danau, pembendungan sungai, dan pembangunan jalan raya, berarti proses fragmentasi bentang lahan dan mengubah serta merusak habitat-habitat kritis. Aktivitasaktivitas ini juga mengganggu siklus hara dan menyebabkan hilangnya biodiversitas. Panen berlebihan Overexploitation is commonplace when it comes to harvesting of wildlife, fisheries, and forests. Over long periods of time, stocks of preferred species are reduced. For example, the giant redwoods that once thrived along the California coast now exist only in remnant patches because of overharvesting. When dominant species like the giant redwoods (arguably the world's tallest tree—one specimen was recorded at 110 meters tall with a circumference of 13.4 meters) are lost, the entire ecosystem becomes transformed. Overharvesting often results in reduced biodiversity of endemic species, while facilitating the invasion of opportunistic species. Limbah / Residu. Discharges from municipal, industrial, and agricultural sources into the air, water, and land have severely compromised many of the earth's ecosystems. The effects are particularly apparent in aquatic ecosystems. In some lakes that lack a natural buffering capacity, acid precipitation has eliminated most of the fish and other organisms. While the visual effect appears beneficial (water clarity goes up) the impact on ecosystem health is devastating. Systems that once contained a variety of organisms and were highly productive (biologically) become devoid of most lifeforms except for a few acid-tolerant bacteria and sediment-dwelling organisms. Introduksi Spesies Eksotik
The spread of exotics has become a problem in almost every ecosystem of the world. Transporting species from their native habitat to entirely new ecosystems can wreck havoc, as the new environments are often without natural checks and balances for the new species. In the Great Lakes Basin, the accidental introduction of two small pelagic fishes, the alewife and the rainbow smelt, combined with the simultaneous overharvesting of natural predators, such as the lake trout, led to a significant decline in native fish species. The introduction of the sea lamprey, an eel-like predacious fish that attacks larger fish, into Lake Erie and the upper Great Lakes further destabilized the native fish community. The sea lamprey contributed to the demise of the deepwater benthic fish community by preying on lake trout, whitefish, and burbot. This contributed to a shift in the fish community from one that had been dominated by large benthics to one dominated by small pelagics (fish found in the upper layers of the lake profile). This shift from bottom-dwelling fish (benthic) to surface-dwelling fish (pelagic) has now been partially reversed by yet another accidental introduction of an exotic: the zebra mussel. As the zebra mussel is a highly efficient filter of both phtyoplankton and zooplankton, its presence has reduced the available food in the surface waters for pelagic fish. However, while the benthic fish community has gained back its dominance, the preferred benthic fish species have not yet recovered owing to the degree of initial degradation. Overall, the increasing dominance by exotics not only altered the ecology, but also reduced significantly the commercial value of the fisheries. Perubahan Global Rapid climate change (or climate warming) is an emerging potential global stress on all of the earth's ecosystems. In evolutionary time, there have of course been large fluctuations in climate. However, for the most part these fluctuations have occurred gradually over long periods of time. Rapid climate change is an entirely different matter. By altering both averages and extremes in precipitation, temperature, and storm events, and by destabilizing the El Niño Southern Oscillation (ENSO), which controls weather patterns over much of the southern Pacific region, many ecosystem processes can become significantly altered. Excessive periods of drought or unusually heavy rains and flooding will exceed the tolerance for many species, thus changing the biotic composition. Flooding and unusually high winds contribute to soil erosion, and at the same time add to nutrient load in rivers and coastal waters. These anthropogenic stresses have compromised ecosystem function in most regions of the world, resulting in ecosystem distress syndrome (EDS). EDS is characterized by a group of signs, including abnormalities in nutrient cycling, productivity, species diversity and richness, biotic structure, disease prevalence, soil fertility, and so on. The consequences of these changes for human health are not inconsiderable. Impoverished biotic communities are natural harbors for pathogens that affect humans and other species.
Kesehatan Ekosistem dan Kesehatan Manusia An important aspect of ecosystem degradation is the associated increased risk to human health. Traditionally, the concern has been with contaminants, particularly industrial chemicals that can have adverse impacts on human development, neurological functions, reproductive functions, and that appear to be causative agents in a variety of carcinomas. In addition to these serious environmental concerns (where the remedies are often technological, including engineering solutions to reduce the release of
contaminants), there are a large number of other risks to human health stemming from ecological imbalance. Ecosystem distress syndrome results in the loss of valued ecosystem services, including flood control, water quality, air quality, fish and wildlife diversity, and recreation. One of the major signs of EDS is increased disease incidence, both in humans and other species. Human population health should thus be viewed within an ecological context as an expression of the integrity and health of the life-supporting capacity of the environment. Ecological imbalances triggered by global climate change and other causes are responsible for increased human health risks.
Hubungan keterkaitan antara jasa-jasa ekosistem, aspek kesejahteraan manusia dan Kesehatan Manusia
Sumber: http://www.mindfully.org/Heritage/2005/Ecosystem-Degradation-Threats9dec05.htm ….. diunduh 1/7/2011 Tekanan-tekanan terhadap ekosistem dapat mengakibatkan gangguan yang tidak terduga pada aspek kesehatan masa mendatang. Beberapa masalah yang sangat serius adalah (Sumber: http://www.who.int/mediacentre/news/releases/2005/pr67/en/index.html:) • Gizi dan Nutrisi: Degradasi ekosistem perikanan dan ekosistem pertanian merupakan factor-faktor penyebab mal-nutrisi yang dialami 800 juta manusia di seluruh dunia. Ada banyak penduduk lainnya yang mengalami defisiensi kronis mikro-nutrient.
Air minum yang aman: Water-associated infectious diseases claim 3.2 million lives, approximately 6% of all deaths globally. Over one billion people lack access to safe water supplies, while 2.6 billion lack adequate sanitation, and related problems of water scarcity are increasing, partly due to ecosystem depletion and contamination. Ketergantungan pada bahan bakar padat: Sekitar 3% dari beban gangguan penyakit global disebabkan oleh pencemaran udara “indoor”, penyebab utama penyakit pernafasan. Banyak penduduk dunia menggunakan bahan bakar padat untuk memasak makanan dan menghangatkan ruangan, merupakan penyebab utama penggundulan hutan. Perubahan Iklim dan Vektor Penyakit
The global infectious disease burden is on the order of several hundred million cases per year. Many vector-borne diseases are climate sensitive. Malaria, dengue fever, hantavirus pulmonary syndrome, and various forms of viral encephalitis are all in this category. All these diseases are the result of arthropod-borne viruses (arboviruses) which are transmitted to humans as a result of bites from blood-sucking arthropods. Global climate change—particularly as it impacts both temperatures and precipitation—is highly correlated with the prevalence of vector-borne diseases. For example, viruses carried by mosquitoes, ticks, and other blood-sucking arthropods generally have increased transmission rates with rising temperatures. St. Louis encephalitis (SLE) serves as an example. The mosquito Culex tarsalis carries this virus. The percentage of bites that results in transmission of SLE is dependent on temperature, with greater transmission at higher temperatures. The temperature dependence of vector-borne diseases is also well illustrated with malaria. Malaria is endemic throughout the tropics, with a high prevalence in Africa, the Indian subcontinent, Southeast Asia, and parts of South and Central America and Mexico. Approximately 2.4 billion people live in areas of risk, with some 350 million new infections occurring annually, resulting in approximately 2 million deaths, predominantly in young children. Untreated malaria can become a life-long affliction—general symptoms include fever, headache, and malaise. The climate sensitivity of malaria arises owing to the nature of the interactions of parasites, vectors, and hosts, all of which impact the ultimate transmission rates to humans. The gestation time required for the parasite to become fully developed within the mosquito host (a process termed sporogony) is from eight to thirty-five days. When temperatures are in the range of 20°C to 27°C, the gestation time is reduced. Rainfall and humidity also have an influence. Both drought and heavy rains tend to reduce the population of mosquitoes that serve as vectors for malaria. In drier regions of the tropics, low rainfall and humidity restricts the survival of mosquitoes. Severe flooding can result in scouring of rivers and destruction of the breeding habitats for the mosquito vector, while intermediate rainfall enhances vector production. Ketidak-seimbangan Ekologis Cholera is a serious and potentially fatal disease that is caused by the bacterium Vibrio cholerae. While not nearly so prevalent as malaria, cases are nonetheless numerous. In 1993, there were 296,206 new cases of cholera reported in South America; 9,280 cases were reported in Mexico; 62,964 cases in Africa; and 64,599
cases in Asia. Most outbreaks in Asia, Africa, and South America have originated in coastal areas. Symptoms of cholera include explosive watery diarrhea, vomiting, and abdominal pain. The most recent pandemic of cholera involved more regions than at any previous time in the twentieth century. The disease remains endemic in India, Bangladesh, and Africa. Vibrio cholerae has also been found in the United States—in the Gulf Coast region of Texas, Louisiana, and Florida; the Chesapeake Bay area; and the California coast. The increase in prevalence of V. cholerae has been strongly linked to degraded coastal marine environments. Nutrient-enriched warmer coastal waters, resulting from a combination of climate change and the use of fertilizers, provides an ideal environment for reproduction and dissemination of V. cholerae. Recent outbreaks of cholera in Bangladesh, for example, are closely correlated with higher sea surface temperatures. V. cholerae attach to the surface of both freshwater and marine copepods (crustaceans), as well as to roots and exposed surfaces of macrophytes (aquatic plants) such as the water hyacinth, the most abundant aquatic plant in Bangladesh. Nutrient enrichment and warmer temperatures give rise to algae blooms and an abundance of macrophytes. The algae blooms provide abundant food for copepods, and the increasing copepod and macrophyte populations provide V. cholerae with habitat. Subsequent dispersal of V. cholerae into estuaries and fresh water bodies allows contact with humans who use these waters for drinking and bathing. Global distribution of marine pathogens such as V. cholerae is further facilitated by ballast water discharged from vessels. Ballast water contains a virtual cocktail of pathogens, including V. cholerae. Two other examples of how ecological imbalances lead to human health burdens concern the increased prevalence of Lyme disease and hantavirus pulmonary disease. Lyme disease, sonamed because it was first positively identified in Lyme, Connecticut, is a crippling arthritic-type disease that is transmitted by spirochete-infected Ixodes ticks (deer ticks). Ticks acquire the infection from rodents, and spend part of their life cycle on deer. Three factors have combined to increase the risk to humans of contracting Lyme disease, particularly in North America: (1) the elimination of natural deer predators, particularly wolves; (2) reforestation of abandoned farmland has created more favorable habitat for deer; and (3) the creation of suburban estates, which the deer find ideal habitat for browsing. The net result is a rising deer population, which increases the chances of humans coming into more contact with ticks. Resistensi Antibiotik dan Praktek Pertanian Antibiotic resistance is a growing threat to public health. Antibiotic resistant strains of Streptococcus pneumoniae, a common bacterial pathogen in humans and a leading cause of many infections, including chronic bronchitis, pneumonia, and meningitis, have greatly increased in prevalence since the mid-1970s. In some regions of the world, up to 70 percent of bacterial isolates taken from patients proved resistant to penicillin and other b-lactam antibiotics. The use of large quantities of antibiotics in agriculture and aquaculture appears to have been a key factor in the development of antibiotic resistance by pathogens in farm animals that subsequently may also infect humans. One of the most serious risks to human health from such practices is vancomycin-resistant enterococci. The use of avoparcin, an animal growth promoter, appears to have compromised the utility of vancomycin, the last antibiotic effective against multi-drug-resistant bacteria. In areas where avoparcin has been used, such as on farms in Denmark and Germany, vancomycin-resistant bacteria have been detected in meat sold in supermarkets. Avoparcin was subsequently banned by the European Union. Another example is the use of ofloxacin to protect chickens from infection and thereby enhance their growth. This drug is closely related to ciprofloxacin, one of the
most widely used antibiotics in the year 2000. There have been cases of resistance to ciprofloxacin directly related to its veterinary use. In the United Kingdom, ciprofloxacin resistance developed in strains of campylobacter, a common cause of diarrhea. Multidrug-resistant strains of salmonella have been traced to European egg production. Ketahanan Pangan dan Air. Praktek pertanian juga dapat menimbulkan sejumlah ancaman bagui kesehatan masyarakat. Sebagian dari hal ini berhubungan dengan jeleknya pengolaan limbah, yang mengakibatkan sejumlah parasit dan bakteri memasuki perairan dan system suplai air minum. Hal yang lain adalah melibatkan transfer lintas spesies pathogen-patogen yang dapat menyerang binatang dan manusia. The most recent and spectacular example is mad cow disease, known as variant Creutzfeldt-Jakob disease in humans, a neuro-degenerative condition that, in humans, is ultimately fatal. The first case of Bovine Spongiform Encephalopathy (BSE), the animal form of the disease, was identified in Southern England in November 1981. By the fall of 2000, an outbreak had also occurred in France, and isolated cases appeared in Germany, Switzerland, and Spain. More than one hundred deaths in Europe were attributed to what has come to be commonly called mad cow disease. Pengelolaan pupuk kandang yang tidak tepat telah berdampak pada munculnya gangguan E. coli 0157:H7 di Walkerton, Ontario, Canada. Risiko kesehatan lainnya yang berhubungan dengan mal-fungsi agroecosystems adalah adanya gangguan periodic cryptosporidiosis, penyakit parasitis yang disebarkan oleh limpasan permukaan (runoff) yang terkontaminasi oleh kotoran ternak yang sakit (terinfeksi). Parasit ini menyebabkan gangguan penyakit perut dan diarrhea pada orang-orang yang immunecompetent dan diarrhea-parah dan kematian pada orang-orang yang immunecompromised. Restorasi Ekosistem Patologi ekosistem dalam beberapa kasus dapat dengan mudah diatasi dengan jalan menghilangkan sumber-sumber stress. Misalnya dalam kasus-kasus degradasi ekosistem yang diakibatkan oleh penambahan bahan kimia toksik, maka penghilangan stress ini dapat memulihkan kembali kesehatan ekosistem.
Restorasi Agroekologis Agroecological restoration is the practice of re-integrating natural systems into agriculture in order to maximize sustainability, ecosystem services, and biodiversity. This is one example of a way to apply the principles of agroecology to an agricultural system. Farms cannot be restored to a purely natural state because of the negative economic impact on farmers, but returning processes, such as pest control to nature with the method of intercropping, allows a farm to be more ecologically sustainable and, at the same time, economically viable. Agroecological restoration works toward this balance of sustainability and economic viability because conventional farming is not sustainable over the long run without the integration of natural systems and because the use of land for agriculture has been a driving force in creating the present world biodiversity
crisis. Its efforts are complementary to, rather than a substitute for, biological conservation. “…biodiversity is just as important on farms and in fields as it is in deep river valleys or mountain cloud forests.” FAO, 15 October 2004 Agriculture creates a conflict over the use of land between wildlife and humans. Though the domestication of crop plants occurred 10,000 years ago, a 500% increase in the amount of pasture and crop land over the last three hundred years has led to the rapid loss of natural habitats. In recent years, the world community acknowledged the value of biodiversity in treaties, such as the 1992 landmark Convention on Biological Diversity. Reintegration The reintegration of agricultural systems into more natural systems will result in decreased yield and produce a more complex system, but there will be considerable gains in biodiversity and ecosystem services. Biodiversitas The Food and Agriculture Organization of the United Nations estimates that more than 40% of earth’s land surface is currently used for agriculture. And because so much land has been converted to agriculture, habitat loss is recognized as the driving force in biodiversity loss (FAO). This biodiversity loss often occurred in two steps, as in the American Midwest, with the introduction of mixed farming carried out on small farms and then with the widespread use of mechanized farming and monoculture beginning after World War II. The decline in farmland biodiversity can now be traced to changes in farming practices and increased agricultural intensity. Peningkatan keaneka-ragaman Heterogeneity (here, the diversity or complexity of the landscape) has been shown to be associated with species diversity. For example, the abundance of butterflies has been found to increase with heterogeneity. One important part of maintaining heterogeneity in the spaces between different fields is made up of habitat that is not cropped, such as grass margins and strips, scrub along field boundaries, woodland, ponds, and fallow land. These seemingly unimportant pieces of land are crucial for the biodiversity of a farm. The presence of field margins benefits many different taxa: the plants attract herbivorous insects, will which attract certain species of birds and those birds will attract their natural predators. Also, the cover provided by the no cropped habitat allows the species that need a large range to move across the landscape. Monokultur In the absence of cover, species face a landscape in which their habitat is greatly fragmented. The isolation of a species to a small habitat that it can’t safely wander from can create a genetic bottleneck, decreasing the resilience of the particular population, and be another factor leading to the decline of the total population of the species. Monoculture, the practice of producing a single crop over a wide area, causes fragmentation. In conventional farming, monoculture, such as with rotations of corn and soybean crops planted in alternating growing
seasons, is used so that very high yields can be produced. After the mechanization of farming, monoculture became a standard practice in cornbeans rotation, and had broad implications for the long-term sustainability and biodiversity of farms. Whereas organic fertilizers, had kept the soil’s nutrients fixed to the ecosystem, the introduction of monoculture removed the nutrients and farmers compensated for that loss by using inorganic fertilizers. It is estimated that humans have doubled the rate of nitrogen input into the nitrogen cycle, mostly since 1975. As a result, the biological processes that controlled the way crops used the nutrients changed and the leached nitrogen from farmland soils has become a source of pollution. Pertanian Organik Organic farming is defined in different legal terms by different nations, but its main distinction from conventional farming is that it prohibits the use of synthetic chemicals in crop and livestock production. Often, it also includes diverse crop rotations and provides non-cropped habitat for insects that provide ecosystem services, such as pest control and pollination. However, it is merely encouraged that organic farmers follow those kinds of wildlife friendly practices, and as a result there is a great difference between the ecosystem services that similarly sized but distinctly managed organic farms provide. A recent review of the 76 studies concerning the relationship between biodiversity and organic farming listed three practices associated with organic farming that accounted for the higher biodiversity counts found in organic farms as compared to conventional farms. 1. Prohibition/reduced use of chemical pesticides and inorganic fertilizers is likely to have a positive impact through the removal of both direct and indirect negative effects on arable plants, invertebrates and vertebrates. 2. Sympathetic management of non-crop habitats and field margins can enhance diversity and abundance of arable plants, invertebrates, birds and mammals. 3. Preservation of mixed farming is likely to positively impact farmland biodiversity through the provision of greater habitat heterogeneity at a variety of temporal and spacial scales within the landscape. Degradasi Ekosistem Degradasi ekosistem: Degradasi atau destruksi lingkungan alam sekala luas. Kalau suatu ekosistem mengalami gangguan akibat dari peristiwa alam atau kegiatan manusia maka sangat sulit untuk menghitung dampak yang dialami oleh seluruh alam. Kalau dua atau lebih ekosistem mengalami degradasi maka peluang terjadinya destruktif sinergistik akan berlipat-ganda. Ecosistem-ekosistem di banyak daerah akan terancam, dengan segala kekayaan biologisnya dan potensi manfaat materialnya. (Source: WPR) Degradasi Ekosistem: Tanggungjawab Moral terhadap Planet Bumi Kegiatan manusia telah berdampak pada degradasi ekosistem. Karena planet, binatang dan lingkungan semuanya saling berinteraksi, maka perubahan yang berlangsung dalam ekosistem akan mempunyai dampak negative terhadap
kehidupan dan planet bumi ini. Oleh karena itu, kita semua wajib untuk mengendalikan kegiatan-kegiatan manusia guna mewujudkan kelestarian planet bumi di masa mendatang yang lebih nyaman dan lebih aman. Kita semua manusia perlu bernafas dalam udara segar, hal yang tidak mungkin terjadi kalau pembakaran bahan bakar fosil masih berlebihan. Hal ini akan menyesakkan nafas berbagai spesies oprganisme dan mengakibatkan perubahan iklim yang menjadi ekstrim. Aktivitas manusia telah mengakibatkan perubahan pola lingkungan hidup dunia. Aktivitas lainnya yang juga menyebabkan kerusakan ekosistem adalah perikanan, pemanfaatan air tawar, dan penebangan /penggundulan huitan. Penebangan hutan telah mengakibatkan kandungan CO2 atmosfir meningkat dan mengakibatkan punahnya beberapa spesies. Siklus lingkungan telah mengalami perubahan drastic akibat kegiatan manusia. Ada kerusakan parah pada lapisan ozon. Bagaimana kita akan dilindungi dari bahaya radiasi ultraviolet? Bagaimana kita harus melindungi lapisan ozon ini? Masing-masing dari kita semua , harus mengambil rtanggung-jawab ini untuk mereduksi emisi CO2 dengan jalan menanam lebih banyak pohon sehingga jalur-jalur hijau melindungi semua kehidupan. Oleh karena itu penyelamatan planet bumi dari kepunahan berada di tangan kita manusia semuanya. (Sumber: http://EzineArticles.com/3784225)
Gambar berikut ini menunjukkan keterkaitan antara tekanan penduduk, fenomena kekeringan, proses-proses degradasi, desertification, dan kerentanan pangan.
Sumber: http://ag.arizona.edu/~lmilich/envsec.html ….. diunduh 2/7/2011
Keterkaitan antara Ketahanan pangan rumahtangga dan Ketahanan Lingkungan: Siklus Kemiskinan-Degradasi Lingkungan
Sumber: http://ag.arizona.edu/~lmilich/envsec.html ….. diunduh 2/7/2011
Mencegah Degradasi Ekosistem Memulihkan kembali degradasi ekosistem sangatlah sulit, dan banyak sekali risiko kesehatan manusia telah bermunculan akibat dari hilangnya kesehatan ekosistem, pendekatan yang paluing efektif sebenarnya adalah mencegah terjadinya kerusakan ekosistem. Akan tetapi pendekatan seperti ini tidak mudah dilaksanakan, ada beragam kendala menghadang. Di Negara-negara sedang berkembang dan Negara-negara maju ada inklinasi yang kuat untuk melanjutkan pertumbuhan ekonominya, meskipun dengan biaya mahal berupa kerusakan lingkungan yang parah. Terlepas dari motivasi egokemandirian, argumentasi yang diambil ialah bahwa pertumbuhan ekonomi mempunyai banyak manfaat nyata bagi kesehatan, seperti penyediaan sarana yang lebih efisien untuk distribusi pangan, penyediaan pangan yang lebih baik, dan penyediaan layanan kesehatan yang elbih bagus, serta pendanaan untuk penelitian memperbaiki standard kehidupan. Ini semuanya memang manfaat dari pembangunan ekonomi, dan telah berhasil meningkatkan status kesehatan penduduk dunia. However, at the dawn of the twenty-first century, the past is not necessarily the best guide to the future. The human population is at an alltime high, and associated pressures of human activity have led to increasing degradation of the earth's ecosystems. As ultimately healthy ecosystems are essential for life of all biota, including humans, current global and regional trends are ominous. Under these circumstances, a tradeoff between immediate material gains and long-term sustainability of humans on the planet may be the only option. If so, the solution to sustaining human health and ecosystem health becomes one of devising a new politic that places sustaining lifesupport systems as a precondition for betterment of the human condition.
Pertanian = Agriculture The word agriculture is the English adaptation of Latin agricultūra, from ager, "a field", and cultūra, "cultivation" in the strict sense of "tillage of the soil". Thus, a literal reading of the word yields "tillage of a field / of fields". Agriculture is the cultivation of animals, plants, fungi and other life forms for food, fiber, and other products used to sustain life. Agriculture was the key implement in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that nurtured the development of civilization. The study of agriculture is known as agricultural science. Agriculture is also observed in certain species of ant and termite, but generally speaking refers to human activities. The history of agriculture dates back thousands of years, and its development has been driven and defined by greatly different climates, cultures, and technologies. However, all farming generally relies on techniques to expand and maintain the lands suitable for raising domesticated species. For plants, this usually requires some form of irrigation, although there are methods of dryland farming; pastoral herding on rangeland is still the most common means of raising livestock. In the developed world, industrial agriculture based on large-scale monoculture has become the dominant system of modern farming, although there is growing support for sustainable agriculture (e.g. permaculture or organic agriculture). Modern agronomy, plant breeding, pesticides and fertilizers, and technological improvements have sharply increased yields from cultivation, but at the same time have caused widespread ecological damage and negative human health effects. Selective breeding and modern practices in animal husbandry such as intensive pig farming have similarly increased the output of meat, but have raised concerns about animal cruelty and the health effects of the antibiotics, growth hormones, and other chemicals commonly used in industrial meat production. The major agricultural products can be broadly grouped into foods, fibers, fuels, and raw materials. In the 21st century, plants have been used to grow biofuels, biopharmaceuticals, bioplastics, and pharmaceuticals. Specific foods include cereals, vegetables, fruits, and meat. Fibers include cotton, wool, hemp, silk and flax. Raw materials include lumber and bamboo. Other useful materials are produced by plants, such as resins. Biofuels include methane from biomass, ethanol, and biodiesel. Cut flowers, nursery plants, tropical fish and birds for the pet trade are some of the ornamental products. Sistem Produksi Tanaman Cropping systems vary among farms depending on the available resources and constraints; geography and climate of the farm; government policy; economic, social and political pressures; and the philosophy and culture of the farmer. Shifting cultivation (or slash and burn) is a system in which forests are burnt, releasing nutrients to support cultivation of annual and then perennial crops for a period of several years. Then the plot is left fallow to regrow forest, and the farmer moves to a new plot, returning after many more years (10-20). This fallow period is shortened if population density grows, requiring the input of nutrients (fertilizer or manure) and some manual pest control. Annual cultivation is the next phase of intensity in which there is no fallow period. This requires even greater nutrient and pest control inputs. Further industrialization lead to the use of monocultures, when one cultivar is planted on a large acreage. Because of the low biodiversity, nutrient use is uniform and pests tend to build up, necessitating the greater use of pesticides and fertilizers.
Multiple cropping, in which several crops are grown sequentially in one year, and intercropping, when several crops are grown at the same time are other kinds of annual cropping systems known as polycultures. In tropical environments, all of these cropping systems are practiced. In subtropical and arid environments, the timing and extent of agriculture may be limited by rainfall, either not allowing multiple annual crops in a year, or requiring irrigation. In all of these environments perennial crops are grown (coffee, chocolate) and systems are practiced such as agroforestry. In temperate environments, where ecosystems were predominantly grassland or prairie, highly productive annual cropping is the dominant farming system. The last century has seen the intensification, concentration and specialization of agriculture, relying upon new technologies of agricultural chemicals (fertilizers and pesticides), mechanization, and plant breeding (hybrids and GMO's). In the past few decades, a move towards sustainability in agriculture has also developed, integrating ideas of socio-economic justice and conservation of resources and the environment within a farming system. This has led to the development of many responses to the conventional agriculture approach, including organic agriculture, urban agriculture, community supported agriculture, ecological or biological agriculture, integrated farming and holistic management, as well as an increased trend towards agricultural diversification. Sistem Produksi Ternak Animals, including horses, mules, oxen, camels, llamas, alpacas, and dogs, are often used to help cultivate fields, harvest crops, wrangle other animals, and transport farm products to buyers. Animal husbandry not only refers to the breeding and raising of animals for meat or to harvest animal products (like milk, eggs, or wool) on a continual basis, but also to the breeding and care of species for work and companionship. Livestock production systems can be defined based on feed source, as grassland based, mixed, and landless. Grassland based livestock production relies upon plant material such as shrubland, rangeland, and pastures for feeding ruminant animals. Outside nutrient inputs may be used, however manure is returned directly to the grassland as a major nutrient source. This system is particularly important in areas where crop production is not feasible because of climate or soil, representing 30-40 million pastoralists. Mixed production systems use grassland, fodder crops and grain feed crops as feed for ruminant and monogastic (one stomach; mainly chickens and pigs) livestock. Manure is typically recycled in mixed systems as a fertilizer for crops. Approximately 68% of all agricultural land is permanent pastures used in the production of livestock. Landless systems rely upon feed from outside the farm, representing the delinking of crop and livestock production found more prevalently in OECD member countries. In the U.S., 70% of the grain grown is fed to animals on feedlots. Synthetic fertilizers are more heavily relied upon for crop production and manure utilization becomes a challenge as well as a source for pollution. Pendekatan untuk mereduksi limbah ternak dan pencemaran lingkungan: 1. Supply nutrients to the required level. This can be accomplished by better knowledge of nutrient availability (N, P) in the feed, a better knowledge of the animals requirement and a better agreement of supply and requirement. 2. Enhance digestibility of P and protein. Use of microbial phytase to improve digestibility of P reduces needs for supplementation; enzyme treatment of
non-starch polysaccharides; reduce anti-nutritional factors through treatment of ingredients and processing of complete diets. 3. Change feedstuff composition. For example selection of highly digestible sources of P (mono-calcium phosphate rather than di-calcium); use of amino acid supplementation and reduction in protein levels. 4. Memperbaiki efisiensi pakan. Dampak lingkungan lainnya: 1. Levels of potassium supply exceed demand by a factor of 3-5 and levels in fresh water can exceed accepted levels by a factor of 2-4. 2. High moisture level of livestock waste increases transport costs for disposal. 3. Although feed additives may reduce excretion of N and P as a result of better feed conversion, copper and zinc growth promotants can accumulate in soils. 4. Free-ranging pigs requiring more fibre in the diet have lower feed conversion and more waste per unit of meat produced. 5. Specific pathogen-free herds can improve feed conversion by 10-15 percent. Sumber: Jongbloed and Lenis (1995)
Pertanian-Ekologis = Ecoagriculture Ecoagriculture describes landscapes that support both agricultural production and biodiversity conservation, working in harmony together to improve the livelihoods of rural communities. While many rural communities have independently practiced ecoagriculture for thousands of years, over the past century many of these landscapes have given way to segregated land use patterns, with some areas employing intensive farming practices without regard to biodiversity impacts, and other areas fenced off completely for habitat or watershed protection. A new ecoagriculture movement is now gaining momentum to unite land managers and other stakeholders from diverse environments to find compatible ways to conserve biodiversity while also enhancing agricultural production. "Ecoagriculture" is a term coined in 2000 (by Sara Scherr and Jeffrey McNeely) to convey a vision of rural communities managing their resources to jointly achieve three broad goals at a landscape scale — what we refer to as the “three pillars” of ecoagriculture: • Enhance rural livelihoods; • Conserve or enhance biodiversity and ecosystem services; and • Develop more sustainable and productive agricultural systems. Ecoagriculture is both a conservation strategy and a rural development strategy. Ecoagriculture recognizes agricultural producers and communities as key stewards of ecosystems and biodiversity and enables them to play those roles effectively. Ecoagriculture applies an integrated ecosystem approach to agricultural landscapes to address all three pillars, drawing on diverse elements of production and conservation management systems. Meeting the goals of ecoagriculture usually requires collaboration or coordination between diverse stakeholders who are collectively responsible for managing key components of a landscape.
As an alternative strategy to industrial agriculture, an ecoagriculture approach works by mimicking natural systems to create a new ecosystem, one consisting mainly of perennials and indigenous species. There are many names for ecoagricultural systems; permaculture, natural systems agriculture, agroecology, and while doctrinaires will expound the differences between these labels, all work on the same principals and emulate basic analogous concepts. By mimicking and re-creating an ecosystem, biodiversity, stability, fertility, resilience and resistance are increased, there-by strengthening the overall agricultural system. Chemical additions are not required as the system is closed and entirely self-supportive, additionally needed amendments will be provided from organic by-products of the system. Ecoagriculture systems have been shown to be effective in both climate change mitigation and adaptation, while being extremely productive as a food source. Ecoagriculture systems “have been described as domesticated ecosystems” . The premise works similarly to a forest, or a prairie, or any other ecosystem. A forest is an entirely contained system, each individual part making the whole stronger. A forest does not require outside fertilizers or pesticides or irrigation, yet nutrients in the soil, insect ratios, water are typically keep in proper balance. “This system, thus, maintains
its own health, runs on the sun's energy, recycles nutrients, and at no expense to the planet or people.” Using these concepts, ecoagriculture designs a system allowing these processes to work with the land, to achieve the desired outcome of an increased, diverse food supply.
Pohon ditanam pada guludan untuk memanfaatkan air hujan yang tertampung pada parit (swale) Sumber: http://climatelab.org/Ecoagriculture ..... diunduh 30/6/2011 Ecoagriculture is both a conservation strategy and a rural development strategy. Ecoagriculture recognizes agricultural producers and communities as key stewards of ecosystems and biodiversity and enables them to play those roles effectively. Ecoagriculture applies an integrated ecosystem approach to agricultural landscapes to address all three pillars -- conserving biodiversity, enhacing agricultural production, and improving livelihoods -- drawing on diverse elements of production and conservation management systems. Meeting the goals of ecoagriculture usually requires collaboration or coordination between diverse stakeholders who are collectively responsible for managing key components of a landscape. Pertanian Berkelanjutan = Sustainable agriculture Sustainable agriculture is the practice of farming using principles of ecology, the study of relationships between organisms and their environment. It has been defined as "an integrated system of plant and animal production practices having a site-specific application that will last over the long term: • Satisfy human food and fiber needs • Make the most efficient use of non-renewable resources and on-farm resources and integrate, where appropriate, natural biological cycles and controls
Sustain the economic viability of farm operations Enhance the quality of life for farmers and society as a whole.” Sustainable Agriculture in the United States was addressed by the 1990 farm bill.  More recently, as consumer and retail demand for sustainable products has risen, organizations such as Food Alliance and Protected Harvest have started to provide measurement standards and certification programs for what constitutes a sustainably grown crop. A growing movement has emerged during the past two decades to question the role of the agricultural establishment in promoting practices that contribute to these social problems. Today this movement for sustainable agriculture is garnering increasing support and acceptance within mainstream agriculture. Not only does sustainable agriculture address many environmental and social concerns, but it offers innovative and economically viable opportunities for growers, laborers, consumers, policymakers and many others in the entire food system. Sustainable agriculture integrates three main goals--environmental health, economic profitability, and social and economic equity. A variety of philosophies, policies and practices have contributed to these goals. People in many different capacities, from farmers to consumers, have shared this vision and contributed to it. Despite the diversity of people and perspectives, the following themes commonly weave through definitions of sustainable agriculture. Sustainable agriculture is said to offer three main goals that industrial agriculture has not been successfully accounting for – environmental health and diversity, economic profitability, and social and economic equity. In summary, it looks to promote harmony between agriculture and social responsibility so that the ability of future generations to meet their own needs is not obstructed. In reality, the growth rate of the global human population is rapid, but not something the agricultural industry can’t keep up with.
Sumber: http://lidomain.blogspot.com/ ….. diunduh 30/6/2011
Sustainability rests on the principle that we must meet the needs of the present without compromising the ability of future generations to meet their own needs. Therefore, stewardship of both natural and human resources is of prime importance. Stewardship of human resources includes consideration of social responsibilities such as working and living conditions of laborers, the needs of rural communities, and consumer health and safety both in the present and the future. Stewardship of land and natural resources involves maintaining or enhancing this vital resource base for the long term.
Model Usahatani berkelanjutan To be sustainable, inputs must be less than outputs. Inputs include fuel and all forms of energy, labour and raw materials. Even treatment of wastes must not consume excessive energy. For a farmer to practice sustainable agriculture, he must derive a reasonable income from his efforts. The only purchased inputs are corn and other feed ingredients. From here, all 'wastes' are recycled. Dung, carcasses, etc are all composted and made into high quality humus. Using humus and compost tea and proper management, an acre of land can produce 30 tonnes of high protein napia grass. This is fed to goats and fish. Using humus and compost tea, and selecting low-nitrogen demanding heritage seeds, seperti kacang-kacangan, bayam, terung, dll. we can produce abundant market vegetables.
Model usahatani berkelanjutan sekala mikro (Sumber: http://dqfarm.blogspirit.com/web/ ….. diunduh 30/6/2011) A systems perspective is essential to understanding sustainability. The system is envisioned in its broadest sense, from the individual farm, to the local ecosystem, and to communities affected by this farming system both locally and globally. An emphasis on
the system allows a larger and more thorough view of the consequences of farming practices on both human communities and the environment. A systems approach gives us the tools to explore the interconnections between farming and other aspects of our environment. A systems approach also implies interdisciplinary efforts in research and education. This requires not only the input of researchers from various disciplines, but also farmers, farmworkers, consumers, policymakers and others. Making the transition to sustainable agriculture is a process. For farmers, the transition to sustainable agriculture normally requires a series of small, realistic steps. Family economics and personal goals influence how fast or how far participants can go in the transition. It is important to realize that each small decision can make a difference and contribute to advancing the entire system further on the "sustainable agriculture continuum." The key to moving forward is the will to take the next step. Finally, it is important to point out that reaching toward the goal of sustainable agriculture is the responsibility of all participants in the system, including farmers, laborers, policymakers, researchers, retailers, and consumers. Each group has its own part to play, its own unique contribution to make to strengthen the sustainable agriculture community. The specific strategies for realizing these broad themes or goals of systems . The strategies are grouped according to three separate though related areas of concern: Farming and Natural Resources, Plant and Animal Production Practices, and the Economic, Social and Political Context. They represent a range of potential ideas for individuals committed to interpreting the vision of sustainable agriculture within their own circumstances.
Usaha Pertanian dan Sumberdaya Alam The physical aspects of sustainability are partly understood. Practices that can cause long-term damage to soil include excessive tillage (leading to erosion) and irrigation without adequate drainage (leading to salinization). Long-term experiments have provided some of the best data on how various practices affect soil properties essential to sustainability. The most important factors for an individual site are sun, air, soil and water. Of the four, water and soil quality and quantity are most amenable to human intervention through time and labour.
Sistem Produksi Primer Plants produce plant matter from soil nutrients, water and carbon dioxide, using the energy of light. It is called primary production. The diagram shows the carbon flows (is equal to energy flows). At left one sees a plant receiving light and CO2 from the air and returning oxygen. At night, when there is no sunlight, plants respire like animals do, taking up oxygen and returning CO2. Surprisingly, a large proportion of a plant's primary production (50%) disappears underground, where it grows the root system and feeds soil organisms. Only 50% is used for aboveground growth. Of this, between 10 and 40% is used for growing, depending on plant type, age and kind of harvesting. If the plant is grazed regularly, the grown biomass will be grazed, amounting to no more than 40%. The remaining 10% is
lost by leaf drop. This leaf litter is decomposed by fungi and bacteria, contributing energy to the soil biota, while returning nutrients to the plant
Sumber: http://www.seafriends.org.nz/enviro/soil/ecology.htm ..... diunduh 30/6/2011
Although air and sunlight are available everywhere on Earth, crops also depend on soil nutrients and the availability of water. When farmers grow and harvest crops, they remove some of these nutrients from the soil. Without replenishment, land suffers from nutrient depletion and becomes either unusable or suffers from reduced yields. Sustainable agriculture depends on replenishing the soil while minimizing the use of non-renewable resources, such as natural gas (used in converting atmospheric nitrogen into synthetic fertilizer), or mineral ores (e.g., phosphate). Possible sources of nitrogen that would, in principle, be available indefinitely, include: 1. recycling crop waste and livestock or treated human manure 2. growing legume crops and forages such as peanuts or alfalfa that form symbioses with nitrogen-fixing bacteria called rhizobia 3. industrial production of nitrogen by the Haber Process uses hydrogen, which is currently derived from natural gas, (but this hydrogen could instead be made by electrolysis of water using electricity (perhaps from solar cells or windmills)) or 4. genetically engineering (non-legume) crops to form nitrogen-fixing symbioses or fix nitrogen without microbial symbionts.
The last option was proposed in the 1970s, but is only recently becoming feasible. Sustainable options for replacing other nutrient inputs (phosphorus, potassium, etc.) are more limited. More realistic, and often overlooked, options include long-term crop rotations, returning to natural cycles that annually flood cultivated lands (returning lost nutrients indefinitely) such as the Flooding of the Nile, the long-term use of biochar, and use of crop and livestock landraces that are adapted to less than ideal conditions
such as pests, drought, or lack of nutrients. Crops that require high levels of soil nutrients can be cultivated in a more sustainable manner if certain fertilizer management practices are adhered to. Air - Pertanian In some areas, sufficient rainfall is available for crop growth, but many other areas require irrigation. For irrigation systems to be sustainable they require proper management (to avoid salinization) and must not use more water from their source than is naturally replenished, otherwise the water source becomes, in effect, a non-renewable resource. Improvements in water well drilling technology and submersible pumps combined with the development of drip irrigation and low pressure pivots have made it possible to regularly achieve high crop yields where reliance on rainfall alone previously made this level of success unpredictable. However, this progress has come at a price, in that in many areas where this has occurred, such as the Ogallala Aquifer, the water is being used at a greater rate than its rate of recharge. Several steps should be taken to develop drought-resistant farming systems even in "normal" years, including both policy and management actions: 1) improving water conservation and storage measures, 2) providing incentives for selection of drought-tolerant crop species, 3) using reduced-volume irrigation systems, 4) managing crops to reduce water loss, or 5) not planting at all (. When the production of food and fiber degrades the natural resource base, the ability of future generations to produce and flourish decreases. The decline of ancient civilizations in Mesopotamia, the Mediterranean region, Pre-Columbian southwest U.S. and Central America is believed to have been strongly influenced by natural resource degradation from non-sustainable farming and forestry practices. Water is the principal resource that has helped agriculture and society to prosper, and it has been a major limiting factor when mismanaged. Suplai dan Penggunaan Air An extensive water storage and transfer system has been established which has allowed crop production to expand to very arid regions. In drought years, limited surface water supplies have prompted overdraft of groundwater and consequent intrusion of salt water, or permanent collapse of aquifers. Periodic droughts, some lasting up to 50 years, have occurred in any areas. Several steps should be taken to develop drought-resistant farming systems even in "normal" years, including both policy and management actions: 1) improving water conservation and storage measures, 2) providing incentives for selection of drought-tolerant crop species, 3) using reduced-volume irrigation systems, 4) managing crops to reduce water loss, or 5) not planting at all. Kualitas Air. The most important issues related to water quality involve salinization and contamination of ground and surface waters by pesticides, nitrates and selenium. Salinity has become a problem wherever water of even relatively low salt content is used on shallow soils in arid regions and/or where the water table is near the root zone of crops. Tile drainage can remove the water and salts, but the disposal of the salts and other contaminants may negatively affect the environment depending upon where they are deposited. Temporary solutions include the use of salt-tolerant crops, low-volume irrigation, and various management techniques to minimize the effects of salts on crops. In the long-term, some farmland may need to be removed from production or converted to other uses. Other uses include conversion of row crop land to production of drought-tolerant forages, the
restoration of wildlife habitat or the use of agroforestry to minimize the impacts of salinity and high water tables Indicators for sustainable water resource development are: ¤ Internal renewable water resources. This is the average annual flow of rivers and groundwater generated from endogenous precipitation, after ensuring that there is no double counting. It represents the maximum amount of water resource produced within the boundaries of a country. This value, which is expressed as an average on a yearly basis, is invariant in time (except in the case of proved climate change). The indicator can be expressed in three different units: in absolute terms (km3/yr), in mm/yr (it is a measure of the humidity of the country), and as a function of population (m3/person per yr). ¤ Global renewable water resources. This is the sum of internal renewable water resources and incoming flow originating outside the country. Unlike internal resources, this value can vary with time if upstream development reduces water availability at the border. Treaties ensuring a specific flow to be reserved from upstream to downstream countries may be taken into account in the computation of global water resources in both countries. ¤ Dependency ratio. This is the proportion of the global renewable water resources originating outside the country, expressed in percentage. It is an expression of the level to which the water resources of a country depend on neighbouring countries. ¤ Water withdrawal. In view of the limitations described above, only gross water withdrawal can be computed systematically on a country basis as a measure of water use. Absolute or per-person value of yearly water withdrawal gives a measure of the importance of water in the country's economy. When expressed in percentage of water resources, it shows the degree of pressure on water resources. A rough estimate shows that if water withdrawal exceeds a quarter of global renewable water resources of a country, water can be considered a limiting factor to development and, reciprocally, the pressure on water resources can have a direct impact on all sectors, from agriculture to environment and fisheries. Tanah-pertanian Soil erosion is fast becoming one of the worlds greatest problems. It is estimated that "more than a thousand million tonnes of southern Africa's soil are eroded every year. Experts predict that crop yields will be halved within thirty to fifty years if erosion continues at present rates." Soil erosion is not unique to Africa but is occurring worldwide. The phenomenon is being called Peak Soil as present large scale factory farming techniques are jeopardizing humanity's ability to grow food in the present and in the future. Without efforts to improve soil management practices, the availability of arable soil will become increasingly problematic. Beberapa teknik pengelolaan tanah 1. Pertanian tanpa olah tanah (No-till farming) 2. Keyline design 3. Menanam tumbuhan penahan angin untuk melindungi tanah 4. Mengembalikan bahan organic ke dalam tanah 5. Menghentikan penggunaan pupuk-pupuk kima 6. Melindungi tanah dari air runoff.. Berfungsinya ekosistem tanah
Chemical decomposing activity can be found throughout the soil, but it is most active in five special areas. They are the arenas where activity concentrates. The drilosphere is the workplace of earth worms. As can be seen from the top right drawing, worms leave a funnel-shaped business end on top of previous funnels. Earth is cast on top and to the side, covering leaf litter in a loose fashion. In the oxygen-rich moisture, other organisms find shelter or actively take part in some of the process. Rainwater dissolves nitrates, DOC (Dissolved Organic Carbon) and transports it down the worm hole. The detritusphere works where leaf litter is moist and rich in oxygen. Here fungi can work efficiently, decomposing cellulose while taking oxygen in and respirating carbon dioxide. Inside anoxic corners of leaf structure, bacteria convert nitric oxides to nitrogen.
Sumber: http://www.seafriends.org.nz/enviro/soil/ecology.htm ..... diunduh 30/6/2011
Where masses of young roots are found, activity is high in the porosphere of the soil. Pores are necessary to hold water and to transport oxygen and carbon dioxide. Aggregates of soil are pierced by hair roots (yellow) and covered in hyphae of fungi (purple). By the transport channels from worms and other organisms, water, nitrates, phosphorus and dissolved organic carbon compounds leach from the top down. In the aggregatusphere, sand and clay particles form enclosed workshops for bacteria. Many chemical processes happen here, producing nitrates (NO3-), ammonia (NH4+), carbon dioxide (CO2), nitric oxides and more. Many compounds are transported by the fine hyphae to other places.
Sumber:: http://www.seafriends.org.nz/enviro/soil/ecology.htm ..... diunduh 30/6/2011
The rhizosphere is the area directly around hair roots. This is a special place because hair roots bring food and oxygen, enabling the micro organisms to work faster than anywhere else. A continuous flow of water is caused, as water is absorbed by these roots, drawing with it dissolved substances. As these hair roots grow, they intrude into other aggregatuspheres, find nutrients, get eaten, and other fine roots take their place. The soil is in a continuous state of decomposition, provided moisture and oxygen are available.
Udara-pertanian Many agricultural activities affect air quality. These include smoke from agricultural burning; dust from tillage, traffic and harvest; pesticide drift from spraying; and nitrous oxide emissions from the use of nitrogen fertilizer. Options to improve air quality include incorporating crop residue into the soil, using appropriate levels of tillage, and planting wind breaks, cover crops or strips of native perennial grasses to reduce dust. Ekonomi - Pertanian Socioeconomic aspects of sustainability are also partly understood. Regarding less concentrated farming, the best known analysis is Netting's study on smallholder systems through history. The Oxford Sustainable Group defines sustainability in this
context in a much broader form, considering effect on all stakeholders in a 360 degree approach Given the finite supply of natural resources at any specific cost and location, agriculture that is inefficient or damaging to needed resources may eventually exhaust the available resources or the ability to afford and acquire them. It may also generate negative externality, such as pollution as well as financial and production costs. The way that crops are sold must be accounted for in the sustainability equation. Food sold locally does not require additional energy for transportation (including consumers). Food sold at a remote location, whether at a farmers' market or the supermarket, incurs a different set of energy cost for materials, labour, and transport. Metode-metode Pertanian What grows where and how it is grown are a matter of choice. Two of the many possible practices of sustainable agriculture are crop rotation and soil amendment, both designed to ensure that crops being cultivated can obtain the necessary nutrients for healthy growth. Soil amendments would include using locally available compost from community recycling centers. These community recycling centers help produce the compost needed by the local organic farms. Many scientists, farmers, and businesses have debated how to make agriculture sustainable. Using community recycling from yard and kitchen waste utilizes a local area's commonly available resources. These resources in the past were thrown away into large waste disposal sites, are now used to produce low cost organic compost for organic farming. Other practices includes growing a diverse number of perennial crops in a single field, each of which would grow in separate season so as not to compete with each other for natural resources. This system would result in increased resistance to diseases and decreased effects of erosion and loss of nutrients in soil. Nitrogen fixation from legumes, for example, used in conjunction with plants that rely on nitrate from soil for growth, helps to allow the land to be reused annually. Legumes will grow for a season and replenish the soil with ammonium and nitrate, and the next season other plants can be seeded and grown in the field in preparation for harvest. Monoculture, a method of growing only one crop at a time in a given field, is a very widespread practice, but there are questions about its sustainability, especially if the same crop is grown every year. Today it is realized to get around this problem local cities and farms can work together to produce the needed compost for the farmers around them. This combined with growing a mixture of crops (polyculture) sometimes reduces disease or pest problems but polyculture has rarely, if ever, been compared to the more widespread practice of growing different crops in successive years (crop rotation) with the same overall crop diversity. Cropping systems that include a variety of crops (polyculture and/or rotation) may also replenish nitrogen (if legumes are included) and may also use resources such as sunlight, water, or nutrients more efficiently (Field Crops Res. 34:239). Replacing a natural ecosystem with a few specifically chosen plant varieties reduces the genetic diversity found in wildlife and makes the organisms susceptible to widespread disease. The Great Irish Famine (1845–1849) is a well-known example of the dangers of monoculture. In practice, there is no single approach to sustainable agriculture, as the precise goals and methods must be adapted to each individual case. There may be some techniques of farming that are inherently in conflict with the concept of sustainability, but there is widespread misunderstanding on impacts of some practices. Today the growth of local farmers' markets offer small farms the ability to sell the products that they have grown back to the cities that they got the recycled compost
from. By using local recycling this will help move people away from the slash-and-burn techniques that are the characteristic feature of shifting cultivators are often cited as inherently destructive, yet slash-and-burn cultivation has been practiced in the Amazon for at least 6000 years; serious deforestation did not begin until the 1970s, largely as the result of Brazilian government programs and policies.  To note that it may not have been slash-and-burn so much as slash-and-char, which with the addition of organic matter produces terra preta, one of the richest soils on Earth and the only one that regenerates itself. There are also many ways to practice sustainable animal husbandry. Some of the key tools to grazing management include fencing off the grazing area into smaller areas called paddocks, lowering stock density, and moving the stock between paddocks frequently. Several attempts have been made to produce an artificial meat, using isolated tissues to produce it in vitro; Jason Matheny's work on this topic, which in the New Harvest project, is one of the most commented. Perlakuan Tanah pertanian Soil steaming can be used as an ecological alternative to chemicals for soil sterilization. Different methods are available to induce steam into the soil in order to kill pests and increase soil health. Community and farm composting of kitchen, yard, and farm organic waste can provide most if not all the required needs of local farms. This composting could potentially be a reliable source of energy. Apa itu Kompos? Compost is a rich healthy humus type fertiliser and soil conditioner that results from the decay of organic waste. Organic waste is used to describe a waste that was once living such as grass, leaves, vegetable peelings, cooked food etc. Composting is simply a means of creating the right conditions to accelerate this decay of waste.
Sumber: http://www.bionetix.co.uk/static/Compost_Info_and_Tips/ ….. diunduh 30/6/2011 Dampak eksternal A farm that is able to "produce perpetually", yet has negative effects on environmental quality elsewhere is not sustainable agriculture. An example of a case in which a global view may be warranted is over-application of synthetic fertilizer or animal manures, which can improve productivity of a farm but can pollute nearby rivers and coastal waters (eutrophication). The other extreme can also be undesirable, as the problem of low crop yields due to exhaustion of nutrients in the soil has been related to rainforest destruction, as in the case of slash and burn farming for livestock feed. Agricultural activities contribute strongly to eutrophication and the spread of pollutions in the basin.
Sumber: http://www.zoologi.su.se/ekoklim/study_region.html ..... diunduh 30/6/2011
The chain of eutrophication begins with an overload of nutrients that enters the aquatic ecosystem. This schematic show various nutrient pathways and their effects. The future half of the diagram shows improved water quality based on better nutrient filtering.
Sumber: http://landsat.gsfc.nasa.gov/news/news-archive/soc_0017.html ..... diunduh 30/6/2011
Sustainability affects overall production, which must increase to meet the increasing food and fiber requirements as the world's human population expands to a projected 9.3 billion people by 2050. Increased production may come from creating new farmland, which may ameliorate carbon dioxide emissions if done through reclamation of desert as in the worlds, or may worsen emissions if done through slash and burn farming. Additionally, Genetically modified organism crops show promise for radically increasing crop yields, although many people and governments are apprehensive of this new farming method.
Genetically modified organisms (GMOs) Genetically modified organism (GMO) is an organism that was changed using methods of modern biotechnology. In such organism defined gene for exactly defined characteristic from other organism has been inserted. GMO are microorganisms (bacteria, fungi, and viruses), plants and animals. According to Slovene legislation ''GMO is an organism, with the exception of human beings, or a micro-organism, in which the genetic material has been altered in a way that does not occur naturally by mating or natural recombination.'' (Management of Genetically Modified Organisms Act (Official Gazette of RS No. 23/2005)) According to EU legislation ''GMO means an organism, with the exception of human beings, in which the genetic material has been altered in a way that does not occur naturally by mating and/or natural recombination.''(Directive 2001/18/EC of the European Parliament and of the Council of 12 March 2001 on the deliberate release into the environment of genetically modified organisms and repealing Council Directive 90/220/EEC - Commission Declaration) According to international Cartagena Protocol ''Living Modified Organism (LMO) means any living organism that possesses a novel combination of genetic material obtained through the use of modern biotechnology.'' (Cartagena Protocol on Biosafety to the Convention on Biological Diversity)
Manfaat Teknologi GMO Tanaman Pertanian • Memperbaiki rasa dan kualitas • Mereduksi waktu pemasakan • Increased nutrients, yields, and stress tolerance • Improved resistance to disease, pests, and herbicides • New products and growing techniques Binatang-Ternak • Hasil produksi yang lebih baik : daging, telur dan susu • Perbaikan kesehatan binatang dan metode diagnosisnya • Peningkatan resistensi, productivity, hardiness, dan efisiensi pakan Lingkungan Hidup • " Bioherbicides dan bioinsecticida” ramah lingkungan • Konservasi tanah, air dan energi • Bio-proses untuk produk kehutanan • Pengelolaan limbah secara lebih baik • Pengolahan lebih efisien. Masyarakat • Meningkatkan kertahanan pangan bagi penduduk yang semakin banyak
Recombinant DNA technology: genetically modified organism production
Sumber: http://www.britannica.com/EBchecked/media/122433/Gene tically-modified-organisms-are-produced-using-scientificmethods-that-include ..... diunduh 30/6/2011
Kontroversi GMO Keamanan • Dampak potensial terhadap kesehatan manusia: allergens, transfer resistensi antibiotic, efek-efek yang belum diketahui. • Dampak potensial terhadap lingkungan: unintended transfer of transgenes through cross-pollination, unknown effects on other organisms (e.g., soil microbes), and loss of flora and fauna biodiversity Access dan Intellectual Property • Dominasi produksi pangan dunia oleh beberapa perusahaan • Meningkatkan ketergantungan Negara berkembang kepada Negara industry maju • Eksploitasi sumberdaya alam secara Biopiracy-foreign Etika • Pelanggaran nilai-nilai intrinsik dari organism alamiah • Tampering with nature by mixing genes among species • Objections to consuming animal genes in plants and vice versa • Stress bagi binatang
Some advocates favour sustainable agriculture as the only system which can be sustained over the long-term. However, organic production methods, especially in transition, yield less than their conventional counterparts and raise the same problems of sustaining populations globally. Organic farming is the form of agriculture that relies on techniques such as crop rotation, green manure, compost and biological pest control to maintain soil productivity and control pests on a farm. Organic farming excludes or strictly limits the use of manufactured fertilizers, pesticides (which include herbicides, insecticides and fungicides), plant growth regulators such as hormones, livestock antibiotics, food additives, and genetically modified organisms. "Organic agriculture is a production system that sustains the health of soils, ecosystems and people. It relies on ecological processes, biodiversity and cycles adapted to local conditions, rather than the use of inputs with adverse effects. Organic agriculture combines tradition, innovation and science to benefit the shared environment and promote fair relationships and a good quality of life for all involved.." —International Federation of Organic Agriculture Movements Productivitas dan Profitabilitas Pertanian Organik Various studies find that versus conventional agriculture, organic crops yielded 91%, or 95-100%, along with 50% lower expenditure on fertilizer and energy, and 97% less pesticides, or 100% for corn and soybean, consuming less energy and zero pesticides. (Stanhill, G. 1990). The comparative productivity of organic agriculture. Agriculture, Ecosystems, and Environment. 30(1-2):1-26). The results were attributed to lower yields in average and good years but higher yields during drought years. A 2007 study compiling research from 293 different comparisons into a single study to assess the overall efficiency of the two agricultural systems has concluded that ...organic methods could produce enough food on a global per capita basis to sustain the current human population, and potentially an even larger population, without increasing the agricultural land base. (Perfecto et al.., in Renewable Agriculture and Food Systems (2007), 22: 86–108 Cambridge University Press: cited in New Scientist 13:46 12 July 2007)
Converted organic farms have lower pre-harvest yields than their conventional counterparts in developed countries (92%) but higher than their low-intensity counterparts in developing countries (132%). This is due to relatively lower adoption of fertilizers and pesticides in the developing world compared to the intensive farming of the developed world. (Badgley, C. et al. .Organic agriculture and the global food supply. Renewable Agriculture and Food Systems (2007), 22: 86-108. Organic farms withstand severe weather conditions better than conventional farms, sometimes yielding 70-90% more than conventional farms during droughts. Organic farms are more profitable in the drier states of the United States, likely due to their superior drought performance. Organic farms survive hurricane damage much better, retaining 20 to 40% more topsoil and smaller economic losses at highly significant levels than their neighbors. Contrary to widespread belief, organic farming can build up soil organic matter better than conventional no-till farming, which suggests long-term yield benefits
from organic farming. An 18-year study of organic methods on nutrient-depleted soil, concluded that conventional methods were superior for soil fertility and yield in a cold-temperate climate, arguing that much of the benefits from organic farming are derived from imported materials which could not be regarded as "self-sustaining".
Profitabilitas Pertanian Organik (Lotter, D. (2003). "Organic Agriculture" (PDF). Journal of Sustainable Agriculture 21 (4). http://donlotter.net/lotter_organicag.pdf.) The decreased cost of synthetic fertilizer and pesticide inputs, along with the higher prices that consumers pay for organic produce, contribute to increased profits. Organic farms have been consistently found to be as or more profitable than conventional farms. Without the price premium, profitability is mixed. Organic production was more profitable in Wisconsin, given price premiums
Agroekosistem http://www.answers.com/topic/agroecosystem#ixzz1f2iWFTtJ An agroecosystem is the basic unit of study for an agroecologist, and is somewhat arbitrarily defined as a spatially and functionally coherent unit of agricultural activity, and includes the living and nonliving components involved in that unit as well as their interactions. An agroecosystem can be viewed as a subset of a conventional ecosystem. As the name implies, at the core of an agroecosystem lies the human activity of agriculture. However, an agroecosystem is not restricted to the immediate site of agricultural activity (e.g. the farm), but rather includes the region that is impacted by this activity, usually by changes to the complexity of species assemblages and energy flows, as well as to the net nutrient balance. Traditionally an agroecosystem, particularly one managed intensively, is characterized as having a simpler species composition and simpler energy and nutrient flows than "natural" ecosystem. Likewise, agroecosystems are often associated with elevated nutrient input, much of which exits the farm leading to eutrophication of connected ecosystems not directly engaged in agriculture. One of the major efforts of disciplines such as agroecology is to promote management styles that blur the distinction between agroecosystems and "natural" ecosystems, both by decreasing the impact of agriculture (increasing the biological and trophic complexity of the agricultural system as well as decreasing the nutrient inputs/outflow) and by increasing awareness that "downstream" effects extend agroecosystems beyond the boundaries of the farm. In the first case, polyculture or buffer strips for wildlife habitat can restore some complexity to a cropping system, while organic farming can reduce nutrient inputs. Efforts of the second type are most common at the watershed scale. An example is the National Association of Conservation Districts' Lake Mendota Watershed Project, which seeks to reduce runoff from the agricultural lands feeding into the lake with the aim of reducing algal blooms. A model for the functionings of an agricultural system, with all inputs and outputs. An ecosystem may be as small as a set of microbial interactions that take place on the surface of roots, or as large as the globe. An agroecosystem may be at the level of the individual plant-soil-microorganism system, at the level of crops or herds of domesticated animals, at the level of farms or agricultural landscapes, or at the level of entire agricultural economies. Ciri-ciri Agroekosistem Agroecosystems differ from natural ecosystems in several fundamental ways. 1. The energy that drives all autotrophic ecosystems, including agroecosystems, is either directly or indirectly derived from solar energy. However, the energy input to agroecosystems includes not only natural energy (sunlight) but also processed energy (fossil fuels) as well as human and animal labor. 2. Biodiversity in agroecosystems is generally reduced by human management in order to channel as much energy and nutrient flow as possible into a few domesticated species.
3. Evolution is largely, but not entirely, through artificial selection where commercially desirable phenotypic traits are increased through breeding programs and genetic engineering. 4. Agroecosystems are usually examined from a range of perspectives including energy flux, exchange of materials, nutrient budgets, and population and community dynamics. Solar energy influences agroecosystem productivity directly by providing the energy for photosynthesis and indirectly through heat energy that influences respiration, rates of water loss, and the heat balance of plants and animals. Nutrient uptake from soil by crop plants or weeds is primarily mediated by microbial processes. Some soil bacteria fix atmospheric nitrogen into forms that plants can assimilate. Other organisms influence soil structure and the exchange of nutrients, and still other microorganisms may excrete ammonia and other metabolic by-products that are useful plant nutrients. There are many complex ways that microorganisms influence nutrient cycling and uptake by plants. Some microorganisms are plant pathogens that reduce nutrient uptake in diseased plants. Larger organisms may influence nutrient uptake indirectly by modifying soil structure or directly by damaging plants. Although agroecosystems may be greatly simplified compared to natural ecosystems, they can still foster a rich array of population and community processes such as herbivory, predation, parasitization, competition, and mutualism. Crop plants may compete among themselves or with weeds for sunlight, soil nutrients, or water. Cattle overstocked in a pasture may compete for forage and thereby change competitive interactions among pasture plants, resulting in selection for unpalatable or even toxic plants. Indeed, one important goal of farming is to find the optimal densities for crops and livestock. Widespread use of synthetic chemical pesticides has bolstered farm production worldwide, primarily by reducing or eliminating herbivorous insect pests. Traditional broad-spectrum pesticides such as DDT, however, can have far-ranging impacts on agroecosystems. For instance, secondary pest outbreaks associated with the use of many traditional pesticides are not uncommon due to the elimination of natural enemies or resistance of pests to chemical control. Growers and pesticide developers in temperate regions have begun to focus on alternative means of control. Pesticide developers have begun producing selective pesticides, which are designed to target only pest species and to spare natural enemies, leaving the rest of the agroecosystem community intact. Many growers are now implementing integrated pest management programs that incorporate the new breed of biorational chemicals with cultural and other types of controls.
ANALISIS AGROEKOSISTEM Agroecosystem analysis is a thorough analysis of an agricultural environment which considers aspects from ecology, sociology, economics, and politics with equal weight. There are many aspects to consider; however, it is literally impossible to account for all of them. This is one of the issues when trying to conduct an analysis of an agricultural environment. In the past, an agroecosystem analysis approach might be used to determine the sustainability of an agricultural system. It has become apparent, however, that the "sustainability" of the system depends heavily on the definition of sustainability chosen by the observer. Therefore, agroecosystem analysis is used to bring the richness of the true complexity of agricultural systems to an analysis to identify reconfigurations of the system (or holon) that will best suit individual situations. Agroecosystem analysis is a tool of the multidisciplinary subject known as Agroecology. Agroecology and agroecosystem analysis are not the same as sustainable agriculture, though the use of agroecosystem analysis may help a farming system ensure its viability. Agroecosystem analysis is not a new practice, agriculturalists and farmers have been doing it since societies switched from hunting and gathering (huntergatherer) for food to settling in one area. Every time a person involved in agriculture evaluates their situation to identify methods to make the system function in a way that better suits their interests, they are performing an agroecosystem analysis. Analisis Agroecosystem dan Pertanian berkelanjutan It is difficult to discuss these differences without the aid of an example. Consider the case of a conventional apple farmer. This farmer may choose to change his farm to conform to the standards of USDA approved organic agriculture because he felt motivated by social or moral norms or the potential of increased profits or a host of other reasons. This farmer evaluated his situation and reconfigured it to try to improve it. Some might look at this situation and conclude that the apple farmer chose organic apple production because it is more sustainable for the environment. But, what if a few years later the farmer finds that he is struggling to make a profit and decides to go back to conventional agriculture? The farmer performed another agroecosystem analysis and arrived at a reconfiguration that some might see as unsustainable. This example illustrates how agroecosystem analysis is not required to lead a more environmentally sustainable form of agriculture. Agroecosystem analysis might produce a reconfiguration that is more economically sustainable or socially sustainable or politically sustainable for a farmer (or other actor). By definition, however, agroecosystem analysis is not required to produce an environmentally sustainable configuration for an agricultural system.
Pendekatan untuk Analisis William L. Bland, from the University of Wisconsin–Madison, developed the idea of a farm as a Holon (philosophy) This term, holon, was originally introduced by Arthur Koestler in 1966, in which he referred to a holon as an entity in which it is a part by itself, a holon, while contributing to a larger entity, which is also a holon. Bland develops this for an agricultural environment or farm as, "The farm holon is both the whole in which smaller holons exists, and a part of larger entities, themselves holons." This idea was expanded upon by Bland and Michael M. Bell University of Wisconsin–Madison in their 2007 article "A holon approach to agroecology," because it is difficult to account for boundary and change when using a systems thinking approach. One major difference between Koestler's holon and the holon idea developed for agroecosystem analysis is that the latter can only be defined as a holon if it has intentionality. The farm itself is a holon and within the farm holon, other holons exist. For example, a farm animal, the farm family, and a farmworker can all be considered holons within the farm. Additionally, the farm is considered a holon which is inpart connected to other holons such as the county in which the farm resides, the bank from which the farmer borrowed money, or the grain elevator where the farmer can sell goods. Things like the tractor or the barn are not holons because they lack intentionality. When conducting an agroecosystem analysis, the analyst should approach the farm as the farm itself and the "ecology of contexts" in which the farm and the farmer function. A "context" is anything that might influence functioning of the farm and cause it to change. According to Bland and Bell, examples of contexts include, "family, farm business, genetic heart disease, and spiritual beliefs." These examples illustrate the breadth of contexts that could influence why farmers do what they do. Bland concluded his model of a farm as a holon by stating, "A farm is not sustainable (disintegrates) when it cannot find an overall configuration that is simultaneously viable in all contexts." Pertanyaan yang harus diperhatikan There is no right or wrong way to evaluate an agroecosystem. It is important to identify all actors in a holon before beginning the analysis. When an analyst accepts the task of analyzing the agroecosystem, first and foremost, it must be approached as to incorporate all elements involved and should derive questions that should be answered. Pertanyaan-pertanyaan seperti: • Apakah faktor-faktor pembatas (holons and contexts) menentukan konfigurasi agroecosystem yang ada sekarang? • Bagaimana mengkuantifikasikan keberl;anjutan suatu usahat pertanian (economi, social, politis, ekologi dan/atau lainnya)? • Bagaimana petani atau keluarga usahatani mempersepsikan suatu agroecosystem? • Apa saja yang dilakukan petani saat ini, dan bagaimana praktek-praktek tersebut mempengaruhi viabilitas agroecosystem? • Dapatkan petani melestarikan kesejahteraannya dengan praktek-praktek yang ada sekarang? • Apakah nilai-nilai yang dianut oleh petani dari darimana asalnya nilai-nilai tersebut? • Apakah petani akan mempertimbangkan alternatif konfigurasi usahataninya?
Manajemen Agroekosistem Organic Agro-Ecosystem Management from Prototyped Organic Farmer Learning Processes. Yuppayao Tokeeree, Sunantha Laowansiri and Sopit Vetayasuporn. 2010. The Social Sciences, 2010 , Volume: 5 , Issue: 6, Page 532-537. Penelitian ini dilakukan untuk mempelajari manajemen agroekosistem organic dan mensintesis proses pembelajaran yang dilakukan oleh petani organic Mr. Kampan Laowongsri. Mr. Kampan adalah prototype petani organic yang menerapkan system pertanian terpadu di propinsi Mahasarakarm. Sistem pertanian terpadu ini sesuai dengan kaidah-kaidah mutual-manajemen antara sumberdaya fisik dan sumberdaya buiologis serta system pemanfataan limbahnya. Limbah pertanian dirombak dan diolah menjadi material yang bermanfaat dan digunakan dalam proses pertanian. Hasil-hasil penelitian ini menunjukkan bahwa keberhasilan system pertanian organic terpadu ini berpangkal dari proses pembelajaran sendiri petani, prinsip kearifan local, dan pengalaman yang telah dilalui dari generasi ke generasi, percobaan-percobaan, saran pemerintah dan suasta, diskusi komunitas dan informasi-informasi lainnya. Sistem pertanian organic terpadu dari Mr. Kampan ini bukan hanya bertumpu pada keragaan usahatani, tetapi juga mewujudkan kelestarian, kelayakan ekonomi, kesejahteraan petani, keramahan lingkungan dan hasil-hasil opertanian yang aman dikonsumsi. Kecuali itu, kelebihan hasil-hasil pertanian dari konsumsi keluarga dapat dijual dan menghasilkan income bagi keluarganya. Prototipe Sistem Pengelolaan Agroekosistem Organik Organic farming is an agricultural production system of foods and fibers in terms of environmental, social and economic sustainability. It concentrates on soil fertilization and paying respect to natural capabilities of plant, animal and agro-ecosystem. The organic farming decreases external production factors and escapes the usage of synthetic chemicals. It mainly emphasizes on the usage of plant refuses, manures, vetch plants (plants of pea family), green manures and other organic refuses for circulating nutrients and energy in farms. This farming includes creating the environmental sustainability by maintaining natural balance and biological diversity that the organic agro-ecosystem management is similar to the nature and accompanies with using local wisdoms. Therefore, the organic farming is an agricultural process relying on the nature with mainly using biological processes to increase products and prevent pests and accompanies with the circulation of resources using in farms for maximum benefit. Hence, the organic farming principle will conform to the local conditions in terms of economy, society, weather and culture. The organic agro-ecosystem management is an important factor leading to the sustainably agricultural development. Regarding to this management, farmers must be diligent and patient in cultivation that there are methods as the followings: soil fertile management by main using of organic matters, circulating plants cultivation emphasizing on local plants, no usage of agricultural machines to maintain and curing soil structural properties, no usage of pesticides, herbicides and other chemicals and soil-covering plants cultivation instead of chemicals usage. Besides, the land management is another factor that is very simportant to be the base of agro-ecosystem built. It regards with various plants
cultivation, internal and inter-relative areas organism management and farm areas allocation that are necessary to have a good plan for creating a new agro-ecosystem of organic farms. These managements actually are the ancient agriculture in local communities of Asian countries. The mutual conditions in food chain and food web interaction including energy exchange have created the ecological sustainability for instances, resource units in farm production, rice cultivation, fish farming and horticultural cultivation can be used to circulate and mutual support in the dimension of resource and energy transferring. Mahasarakarm, a province in Thailand, supports activities of organic farming to farmers. Farmers have started to cultivate plants and domesticate animals with creating the agro-ecosystem balance in farms. Many of them have succeeded in the organic farming management that helps to generate organic or green products creating health benefits to farmers and consumers as well as income to farmers in long term operation. The organic farmer has worked on the basis of agro-ecosystem intention by allocating relevant resources and creating the organic agro-ecosystem in his farm appropriately with local conditions as well as emphasizing on the integrated management comprising the items as follows. Land management: The farmer land has been allocated accordingly with the new agricultural theory. The theory has defined the land proportion of water source: rice field: horticultural field: accommodation as 30: 30: 30: 10, respectively. His farm land proportion was 24.8: 19.7: 45.8: 9.7 due to the performance and adjustment following the suitability of local ecological geography. When in-depth studying of land allocation, his land has been separated into 9 sub-areas i.e., rice field, mixed horticultural and vegetable field, circulating seasonal vegetable field, asparagus field, herbal field, rice filed and pool edges, water source, animal domesticating area and rice straw group. The highest amount land is the water source area for solving the lack of water in summer season. The rice field edge also consumes a large area by constructing the big size edges to protect water drainage from outside lands which contaminate chemicals and prevent flood. Besides, the edges can be used to cultivate plants especially perennial trees. Soil management: The prototyped farmer has fertilized to improve the soil quality by using manures, green manures from vetch plants, fermented manure, biological fermented water, plowing without rice cob burning and reducing soil nutrients by low waste harvesting of products. Furthermore, there are the cultivation of circulating plants for maintaining nutrients balance, the conservation of soil benthos and the protection of soil erosion by cultivating plants on rice filed and pool edges and soil covered plants. Water management: In northeast Thailand, most farmers have faced the drought problem and there is no sufficient water for cultivating plants, especially in summer season. Therefore, the prototyped farmer constructed the pools for water using sufficiently in throughout year. He has allocated the land for water resource about 24.8% that there are 3 pools total containing 10,453 m 3. In addition, he has managed water resource with water supply system by installing small water pumps, PVC pipe lining to cover farm area and installing water sprinkles having specific valve breaker. The breaker will be opened when watering plants at desired time and watering will be controlled suitably to disperse water and protect evaporation. Most sprinkles can easily move for comfortably water supply management and after harvesting they can move out for soil plowing.
Plant and animal management: The prototyped farmer emphasize on biodiversity and mutualism condition among organisms in his farm. There were 139 species and 56 families of plants i.e., 15 species of shrub, 45 species of perennial plant and 79 species of biennial plant. Each species taken to cultivate in the farm had been selected by mixing local wisdom principles with regards to benefits and science bases. The plants were tested in the experimental land until receiving the appropriate species that are mutual basis in the organic agro-ecosystem. Besides, there is the cultivation of circulating seasonal plants accompany with vetch plants in the same field creating good products due to nutrients balance as well as nitrogen cycle. The main characteristic of this farm is the neatly rice cultivation. He has cultivated by using a rice sprout in one hole that one rai (1,600 m 3) uses only 1 kg of seeds. The selected seeds have been cultured for 7 days that a rice sprout has the length about 10-15 cm. Then the sprouts have been transferred to cultivate in the prepared rice filed having sludge characteristic. They have been pulled out by using a spoon to scoop for maintaining the seed left. After that they are transferred to cultivate as soft sticking their seed roots to the field because the sprouts are still young. In the first stage, watering them is like vegetable watering that soil is just soaked until the sprouts were split. In addition, it is necessary to release water out until the appropriate water level because if there is more water in the filed crabs will destroy rice but less water weeds will grow which is wasting time to get rid of them. Therefore, farmers should pay attention in their cultivation and emphasize on the integrated farming system by no mono-crop cultivation and biodiversity consideration. The prototyped organic farmer gave the reasons for organic agro-ecosystem as the followings. The organic farming emphasizes on cultivation for consumption and income circulation all year round. Due to the differences of harvesting period the cultivating plants can be circulated to give production throughout a year. Then, it can help to support farmers in terms of consumption and commerce throughout a year. It helps to protect outbreaks of diseases and pests because pests cannot destroy the area of integrated plants in a wide range. Most cultivating plants are local species that can be found easily. These species are easy in curing and appropriate with annual water amount. Farmers will cultivate herbs for getting rid of pests throughout a year without using from other chemicals. These help to their self-assistance that farmers will use their resources in a sufficient way. Regarding to domesticating animals, there are 7 types i.e., cow, chicken, duck, cricket, frog, fish and pig. Most animals are local species that are tolerant to environmental conditions and easy in domesticating with giving high products. These create income circulation throughout a year. Additionally, these animals help to circulate nutrients and be a source of organic manure. Other natural animals such as earthworm, millipede, ground lizard, predator insect and so on are beneficial for organic decomposition and controlling pests in the fields. Pest management: From the investigation, there were 52 species and 43 families of pests that were 38.46% of pest insects, 42.31% of predator insects, 3.85% of parasites and 15.38% of cross-pollination insects. These proportions show that the beneficial pespts found in the organic farm were higher than the pest insects. There are 3 methods of pest control and management i.e., using wood vinegar, using biological fermented water and cultivating pest controlling plants. Wood vinegar is produced from charcoal burning and the biological fermented water is generated from the fermentation of herbs in the field. These herbal plants are in local forest and have been using since the past such as tuba root (Derris sp.), Ebony,
Nim, Sarcostemma acidum Voigt (Leafless medicinal tree), Stemona sp., Cassia fistula L., Jatropha curcas L. and so on. For using, these plants must be dissolved in water and then sprayed into the cultivating fields as suitably with each type of plants. Regarding with the cultivation for pests controlling, the prototyped organic farmer has cultivated various types of plants, integrated plants, circulating seasonal plants and insect attracting-expelling plants such as marigold, sunflower, sympodium and so on. These cultivations have created the biodiversities of species and disturbed the pests that cannot select the specific plant for living and eating as usual. Hence, they are an alternative choice to control pests naturally instead of using chemicals, including help to reduce risks of farmers. Waste management: The organic agro-ecosystem supports the waste management. The prototype organic farmer has used the occurred wastes to recycle for using in the production processes. The study found that the production and household wastes such as animal manures, vegetable refuses, leaves and solid wastes have been totally recycled. If there are the decomposing wastes such as food refuses, vegetable refuses and leaves he uses most of them to produce the soil fertilizer and some of them to produce the biological fermented water. The fresh vegetable refuses have been used for feeding cricket, chicken and goose. For the recycled wastes such as plastics, paper, glasses and bottles, he has used them as recycling or collecting for sale. The management of organic agro-ecosystem components can introduce the linkage among the components. These management characteristics are duplicated from the nature for producing foods and agricultural products as environmentally friendly system. The organic agroecosystem management of Mr. Kapan Laowongsri is a very good case study because he has created the organic farming system as mutual consideration under the limitations of area, soil, water and air to be appropriate with plants and animals. His management has cooperated between physical and biological resources by emphasizing on soil fertility, water source, weather controlling with perennial plants, plant species selection for mutual conditions and so on. This relationship is from the selection and creation of the prototyped organic farmer with intention and harmonious mixing the new interdisciplinary knowledge and the local wisdom. Each resource has then presented its roles and has linked with the others in the productive ways. Plants and animals in the fields have been arranged to use the physical resources as maximum beneficiaries. His management has helped to circulate nutrients and resources, allocate the selected plants as suitably, fertilize soil and maximize recycled wastes use in his organic farm. These are the interdisciplinary organization creating the knowledge of organic agro-ecosystem. His self-learning processes have crated the understandings of the organic agroecosystem that he began from analyzing the ecosystem components in his farm by appropriately adjusting resource proportion, worker and investment. After that he established the suitable methods accounting with worker and budget in his family and accompanied with learning the organic agro-ecosystem processes. He has been always learning from agricultural study trips, farmer talks and other agricultural academic sources. Then he has used gained knowledge to experiment, Trial and error test and adjust methods to suit with his farm conditions including resource, worker and budget until receiving the appropriate performances of his farm. These performances have generated good products sufficiently for consumption and incomes for circulating in his family and farm.
Model pengelolaan agroekosistem organic dari hasil proses pembelajaran petani organic (Sumber: http://www.medwelljournals.com/fulltext/?doi=sscience.2010.532.537….. diunduh 2/7/2011) The improvement of existing practices and resources with the introduction of alternative types of organic fertilizers are seen as the method most likely to succeed at the present time. Some of the possibilities for maintaining and improving soil fertility are addressed below. Konservasi Tanah No improvement in soil fertility can be contemplated until soil conservation methods are practised. Soils of hills are lost through detrimental agronomic practices such as slicing terrace risers every year, excessive tillage and hoeing in the rainy season, and severe grazing pressure on pasture and forest lands. In order to first check mass soil erosion, improvements to the management of grazing land and degraded forest land are essential. Use of minimum tillage methods, and preventing the practice of slicing tall bariland risers should be adopted to reduce further soil losses. This last
practice should be restricted to those areas where soil loss is not a problem, for example flat khetland as discussed above. Perbaikan Produktivitas Lahan The major reason for declining soil fertility is the need to use the land more intensively because of increasing human population, coupled with a reduction in manure production, so that nutrients extracted by food crops are not adequately replaced. This is the result of a reduction in animal populations in some areas, but is mostly the result of depletion of the animal feed resources from the forest and grass lands, which means that livestock are not realising their full potential the year round. Productivity of open grassland and forest in the mid-hills is estimated to be able to support only 0.54 and 0.31 livestock units/ha respectively, whereas the present stocking rate is about nine to thirteen times greater than the carrying capacity (WyattSmith, 1982). Therefore, urgent attention must be given to resolving this situation by managing the forest resources properly. Productivity from the forest could be increased by giving priority to fodder tree planting, along with the introduction of improved varieties of grasses and legumes between the trees under silvipastoral management systems. Perbaikan Sistem Manajemen Ternak Large herds or flocks of animals of sub-optimal productivity are not worth much in terms of overall agricultural production, and poor management systems do not help to increase the quantity of animal products. Since 46% of manure is lost in grazing away from the farm, it has been estimated that even if the animal numbers in the hills of Nepal were halved, manure production would remain almost what it is at present, provided that it was collected and utilized properly. Stall-feeding could result in a doubling of the amount of dung collected per animal at present. Animal populations already overburden the hill farmer, and it is essential to consider complete stall-feeding in order to use the available feed effectively and maximise manure production. The wastage of valuable urine can be prevented and utilized by improving drainage and constructing a store pit at the animal shed. Losses of manure due to rain and sun could be minimised by providing some kind of simple shelter over the compost heap/pit. Similarly, animal production could be improved by the timely supply of feed and water, without wastage. Straw as a livestock feed can be improved in quality by treatment with urea, and by the practice of ensiling or otherwise preserving the summer surplus of grass and agricultural crop by-products. These could then be consumed during the food scarcity period of winter. Trials to this effect are being carried out under the Fodder Thrust programme previously described. Perbaikan Budidaya Tanaman In order to supply food grain for a steadily increasing human population from a fixed or limited land resource, improvements to existing farming practices are inevitable. From the soil conservation and fertility standpoint, intercropping of grain legumes within the major cropping systems should be encouraged whenever possible. Similarly, planting grasses and legumes on terrace risers, on farm boundaries and on irrigation bunds should be practised more widely. Legume crops such as cowpea, and crops such as oats and berseem can be grown after the rice is harvested using zero tillage, with broadcasted seed while the ground is still moist. Such practices would provide substantial amounts of forage with a minimum of labour, and render the soil more fertile. Improved crop varieties will give more return over local varieties, particularly where intensive cultivation, and irrigation facilities, or other input supplies are available.
However, to achieve this in the hills, government subsidies in addition to technical information may be necessary. Perbaikan Simpanan dan Aplikasi Pupuk / Rabuk Organik Because of a present lack of awareness of correct preparation methods, manure is often mixed with farm and forest waste in a heap, does not decompose properly, and so is inferior in quality. To alleviate such problems, the pit method of composting should be adopted, and if possible a “starter” such as dung slurry, should be applied to assist proper decomposition. However, possible socio-economic constraints need to be evaluated before recommending these changes to farmers on a wide scale, because of the implied extra labour requirements involved. Penggunaan Pupuk Alternatif Additional inputs (fertilizer and technical) are required to increase present productivity. At the stage when supplies of organic manure are insufficient, the use of chemical fertilizer has to be considered. Though costly, and unreliable in supply in the hill districts, the use of chemical fertilizers can supplement FYM in accessible areas. Its careful use, preferably in combination with organic manure, could considerably increase crop yields without causing much deterioration of soil quality. Use of bio-fertilizers, flood water, and appropriate Rhizobium inoculation of legume seeds may also help to reduce the pressure on the supply of FYM, for which forests are presently being sacrificed to feed animals. Kompos dan Pupuk Hijau The present trend of only exploiting green manuring plants should be changed to one of developing their production on a sustainable basis. More than twenty species have been identified that have some sort of role as green manure, but very few are being consciously propagated by farmers. Research into the most suitable species for assessing their quality, and the feasibility of increasing their production should be given high priority. Penguatan Kelembagaan dan Pemberdayaan SDM The limited number of scientists to investigate problems of soil fertility, and also suffers from insufficient infrastructural and technical laboratory facilities at present. This is hampering the development of improved soil conservation and fertility maintenance methods, through lack of technical information and analytical support services.
DAFTAR PUSTAKA Agro-ecosystem Health Project. 1996. Agroecosystem health. University of Guelph, Guelph, Canada. Ahl, V. dan T.F.H.Allen. 1996. Hierarchy Theory: A Vision, Vocabulary, and Epistemology. Columbia University Press, New York. Allen, T. F. H. dan T.B.Starr. 1982. Hierarchy: Perspectives for Ecological Complexity. University of Chicago Press, Chicago. Allen, T. F. H. Tainter, J. A. Pires, J. C. dan T. W. Hoekstra. 2001. Dragnet Ecology-"Just the Facts Ma'am":The Privilege of Science in a Postmodern World. BioScience 51, 475-485. Aristotle. 1987. A New Aristotle Reader. Edited by J. L. Ackrill. Princeton University, Princeton, NJ. Bakhtin, M. 1981. The Dialogic Imagination: Four Essays. University of Texas, Austin, TX. Begon M, Harper JL, Townsend CR. 1990. Ecology: Individuals, Populations and Communities (2nd ed). Blackwell Science, London, 1068p. Bland, B. 2005. A framework for enquiry into agricultural systems. Bland, W.L. and Bell, M.M. 2007. A holon approach to agroecology International Journal of Agricultural Sustainability 5(4), 280-294. Cai Y. and Smit B. 1994. Sustainability in agriculture: A general review. Agriculture, ecosystems and environment 49:299–307. Checkland, P. dan J. Scholes. 1999. Soft Systems Methodology in Action, Including Soft Systems Methodology: A 30-Year Retrospective. Wiley, New York. Conway, G. 1990. Concepts. Ch 2. In Agroecosystem analysis for research and concepts. Winrock Int. Inst. for Agriculture. Morrilton, AK. Cronon, W. 1992. A Place for Stories: Nature, History and Narrative. Journal of American History 78, 1347-1376. Crosson P. 1992. Sustainable agriculture. Resources 106:143–156. Elske van de Fliert dan Ann R. Braun. 1999. Farmer Field School for Integrated Crop Management of Sweetpotato. Field guides and Technical Manual. Bogor, Indonesia: International Potato Center. ISBN 92-9060-216-3. http://www.eseap.cipotato.org/MF-ESEAP/Abstract/FFS-ICM-SP-Ind.htm Flint M.L. dan P.Gouveia. 2001. IPM in Practice: Principles and Methods of Integrated Pest Management. University of California, 296p. Francis, C. 2005. Cobweb polygons (spider diagrams) for visual display of sustainability Gell-Mann, M. 1994. The Quark and the Jaguar. W. H. Freeman, New York, NY. Gell-Mann, M. 1995. Complex Adaptive Systems. In: H. Morowitz & J. Singer (eds.) The Mind, the Brain, and Complex Adaptive Systems, pp. 11–23. Addison-Wesley, New York, NY. Gliessman, S. 2004. Chapter 2, Agroecology and agroecosystems. In D. Rickerl and C. Francis, (ed.) Agroecosystems Analysis. American Society of Agronomy, Madison, WI. Gliessman, S. R. 2004. Agroecology and Agroecosystems. In: D. Rickerl & C. Francis (eds.) Agroecosystem Analysis, pp. 19–29. American Society of Agronomy, Madison, WI. Huffaker C.B. dan A.P. Cutierrez. 1999. Ecological Entomology. John Wiley & Sons, New York, 756p.
ILRI (International Livestock Research Institute). 1998. Enhanced human well-being through improved livestock and natural resource management in the East African Highlands. Research Proposal submitted to IDRC. ILRI, Nairobi, Kenya. Jahn G.C. and J.W.Beardsley. 2000. Interactions of ants (Hymenoptera: Formicidae) and mealybugs (Homoptera: Psedococcidae) on pineapple. Proc. Hawaiian Entomol. 34, 181-185. Koestler, A. 1967. The Ghost in the Machine. London: Hutchinson. 1990 reprint edition, Penguin Group. ISBN 0-14-019192-5. Krebs, CJ. 1978. Ecology: the Experimental Analysis of Distribution and Abundance (2nd ed.). Harper & Row, New York, 678p. Loucks, Orie. 1977. "Emergence of Research on Agro-Ecosystems". Annual Review of Ecology and Systematics 8: 173–192. http://arjournals.annualreviews.org/ doi/pdf/10.1146/ annurev.es.08.110177.001133?cookieSet=1. McNeely, J. and Scherr, S.; 2003. Ecoagriculture: strategies to feed the world and save wild biodiversity. Island Press, London. Michael, P. 1994. Metode Ekologi untuk Penyelidikan Lapangan dan Laboratorium. UI Press : Jakarta. Peart, R. M. dan W.D. Shoup. 2004. Agricultural Systems Management: Optimizing Efficiency and Performance. Marcel Dekker, New York. Rosen, R. 1991. Life Itself: A Comprehensive Inquiry into the Nature, Origin, and Foundation of Life. Columbia University Press, New York. SCC (Science Council of Canada). 1992. Sustainable agriculture: The research challenge. SCC, Ottawa, Canada. Schowalter T.D. 1996. Insect Ecology: An Ecosystem Approach. Academic press, San Diego, 483p. Smit B. and Brklacich M. 1989. Sustainable development and analysis of rural systems. Journal of rural studies 5:405–414. Smit B. and Smithers J. 1994a. Sustainable agriculture: Interpretations, analyses and prospects. Canadian journal of regional science 16(3):499–524. Smit B. and Smithers J. 1994b. Sustainable agriculture and agro-ecosystem health. In: Nielsen N.O. (ed), Agroecosystem health. Proceedings of an international workshop. University of Guelph, Guelph, Canada. pp. 31–38. Smit B., Waltner-Toews D., Rapport D., Wall E., Wichert G., Gwyn E. and Wandel J. 1998. Agro-ecosystem health: Analysis and assessment. University of Guelph, Guelph, Canada. Spedding, C. R. W. 1988. An Introduction to Agricultural Systems. Elsevier Applied Science, New York. Speight M.R., M.D.Hunter dan A.D. Watt. 1999. Ecology of Insects: Concepts and Applications. Blackwell Science, London, 350p. Vayda, A. P. 1986. Holism and Individualism in Ecological Anthropology. Reviews in Anthropology 13, 295-313. Waltner-Toews D. 1994. Ecosystem health: A framework for implementing sustainability in agriculture. In: Nielsen N.O. (ed), Agroecosystem health. Proceedings of an international workshop. University of Guelph, Guelph, Canada. pp. 8–23. Wojtkowski, P.A. 2008. Agroecological Economics: Sustainability and Biodiversity. Elsevier Publishing, NY.