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PENGELOLAAN KESUBURAN TANAH Dikoleksi oleh : Prof.Dr.Ir.Soemarno,M.S . Jurs Tanah FP-UB --- PSLP PPSUB September 2

KOMPENDIUM KAJIAN LINGKUNGAN. PENGELOLAAN KESUBURAN TANAH Dikoleksi oleh : Prof.Dr.Ir.Soemarno,M.S . Jurs Tanah FP-UB --- PSLP PPSUB September 2011. KESUBURAN TANAH.

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PENGELOLAAN KESUBURAN TANAH Dikoleksi oleh : Prof.Dr.Ir.Soemarno,M.S . Jurs Tanah FP-UB --- PSLP PPSUB September 2

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  1. KOMPENDIUM KAJIAN LINGKUNGAN PENGELOLAAN KESUBURAN TANAH Dikoleksioleh : Prof.Dr.Ir.Soemarno,M.S. Jurs Tanah FP-UB --- PSLP PPSUB September 2011

  2. KESUBURAN TANAH Kesuburan Tanah merupakan kemampuan suatu tanah untuk menghasilkan produk tanaman yang diinginkan, pada lingkungan tempat tanah itu berada. Istilah lain yang maknanya hampir sama adalah “produktivitas tanah”. “Kesuburan tanah” berhubungan dengan ketersediaan hara dalam tanah. Produk tanaman dapat berupa: buah, biji, daun, bunga, umbi, getah, eksudat, akar, trubus, batang, biomassa, naungan, penampilan dsb. Tanah memiliki kesuburan yang berbeda-beda tergantung sejumlah faktor pembentuk tanah yang merajai di lokasi tersebut, yaitu: Bahan induk, Iklim, Relief, Organisme, atau Waktu. Tanah merupakan fokus utama dalam pembahasan ilmu kesuburan tanah, sedangkan kinerja tanaman merupakan indikator utama kesuburan tanah. Sumber: http://id.wikipedia.org/wiki/Kesuburan_tanah ….. Diunduh 15/3/2012

  3. TANAH SUBUR Ciri-ciri Tanah Subur: Kayaunsurharaesensial yang tersediauntukpertumbuhantanaman, termasuk nitrogen, phosphorus dankalium. It contains sufficient minerals (trace elements) for plant nutrition, including boron, chlorine, cobalt, copper, iron, manganese, magnesium, molybdenum, sulfur, and zinc. It contains soil organic matter that improves soil structure and soil moisture retention. Soil pH is in the range 6.0 to 6.8 for most plants but some prefer acid or alkaline conditions. Good soil structure, creating well drained soil, but some soils are wetter (as for producing rice) or drier (as for producing plants susceptible to fungi or rot) such as agave. Beraneka-ragammikrobatanahmendukungpertumbuhantanaman. Topsoilnyacukuptebal. Fertile soil has an abundance of plant nutrients including nitrogen, phosphorus and potassium, an abundance of minerals including zinc, manganese, boron, iron, sulfur, cobalt, copper, magnesium, molybdenum, and chlorine and an abundance of organic matter. In addition, fertile soil has a pH ranging from 5.5 to 6.2 and good drainage. (http://www.ecochem.com/t_faq8.html) Tanah Subur Sumber: http://en.wikipedia.org/wiki/Fertility_%28soil%29 ….. Diunduh 15/3/2012

  4. SOIL FERTILITY MANAGEMENT Laura van Schöll, Rienke Nieuwenhuis Agromisa Foundation, Wageningen, 2004. Lack of soil fertility causes decreased yields but many plant diseases are also related to poor soil fertility. If the soil fertility is not good, the crops are not in optimal condition, and are thus more susceptible to diseases and pests. The presence of diseases and pests lowers productivity levels, again threatening further the livelihoods of the rural communities. Such conditions can be avoided by improving the condition of the soil. The presence of organic matter in the soil is fundamental in maintaining the soil fertility. Organic matter in the soil consists of fresh organic matter (leftover of dead plants and animals) and humus. The fresh organic matter is transformed into humus by soil organisms. Humus gives the soil a dark colour and can retain a lot of water and nutrients. The first step in maintaining soil fertility should be directed at maintaining the organic matter content of the soil. This can be done by using appropriate crop husbandry practices and by applying organic manure or compost. If the soil is very deteriorated, applying chemical fertilisers might be necessary. Chemical fertilisers can restore the soil fertility very quickly; because the nutrients are available to the plants as soon as the fertilizers are dissolved in the soil. It takes much longer before organic matter is transformed into humus and has released its nutrients. Sumber: journeytoforever.org/farm_library/AD2.pdf….. Diunduh 15/3/2012

  5. SOIL FERTILITY MANAGEMENT Laura van Schöll, Rienke Nieuwenhuis Agromisa Foundation, Wageningen, 2004. Crop husbandry measures Crop husbandry measures refer to methods the farmer can use before, during and after the growing season that do not require the addition of a new component to his business nor the purchase of many extra inputs (just sowing or planting materials). These measures include mulching, green manuring, intercropping, green fallow periods, and agroforestry. All of the above methods are intended to achieve and retain optimum conditions in the root zone, where the crop gets the nutrients and moisture it needs for good production. Also the soil must be penetrable for plant roots. Methods such as mulching, intercropping and agroforestry aim to keep the soil covered in order to prevent evaporation and dehydration. Intercropping and agroforestry also ensure that extensive root systems are present in the soil; planting different crops with different root systems that need different nutrients contributes to a better utilisation of the available nutrients and water. The trees that form a part of agroforestry systems also ensure that the nutrients in deeper soil layers are utilised. Green manuring and green fallow periods contribute particularly to a higher level of organic matter and to greater availability of the nutrients that are released from the organic material worked into the soil. The latter function can be intensified if leguminous plants are used. Sumber: journeytoforever.org/farm_library/AD2.pdf….. Diunduh 15/3/2012

  6. SOIL FERTILITY MANAGEMENT Laura van Schöll, Rienke Nieuwenhuis Agromisa Foundation, Wageningen, 2004. BAHAN ORGANIK TANAH Organic matter is very important in soil fertility management because it has many properties that help increase soil fertility and improve the soil structure. Organic matter has a great capacity to retain nutrients; this is especially important in sandy soils, which retain very few nutrients. Organic matter can also retain a lot of water, which means that in dry periods more water is available for the plants for a longer time. This is especially important in sandy soils, which retain little water. Organic matter can improve the soil structure. This is important for both sandy and clay soils, because they have a poor structure. Finally, organic matter stimulates the growth of soil organisms, which help make the nutrients in the organic matter available to the plants. The organic matter in the soil consists of fresh organic material and humus. Fresh organic material is plant and animal waste that has not yet decomposed, such as roots, crop residues, animal excrement and cadavers. The fresh material is transformed by soil organisms into humus, which is also called organic soil matter. In the process, nutrients are released; organic matter thus makes nutrients available to the plants. Humus, i.e. organic soil matter, is material that has been broken down so far that the original fresh material is no longer distinguishable. It gives the soil a dark colour. Humus itself is also broken down by the soil organisms, which releases even more nutrients, but this process takes much longer in cold or dry conditions. Sumber: journeytoforever.org/farm_library/AD2.pdf….. Diunduh 15/3/2012

  7. SOIL FERTILITY MANAGEMENT Laura van Schöll, Rienke Nieuwenhuis Agromisa Foundation, Wageningen, 2004. BAHAN ORGANIK TANAH Crop husbandry that contributes to a positive balance of organic matter is the basis for good soil fertility in the long term. The balance of organic matter must be even or positive, that is, the amount of organic matter that is added must be equal to or greater than the amount that is broken down and thereby lost. However a positive balance of organic matter is difficult to achieve. This means that if a lot of organic matter is lost (by erosion for example) it is difficult to increase the level of organic matter in the soil. Even in favorable conditions and with good crop management, this can take a number of decades, especially if during that time crops are grown that are almost completely removed with the harvest. The rate at which organic matter is broken down depends largely on the climate. In warm, damp conditions the organic matter is broken down faster than in cold or dry conditions. Cover crops are gaining favor as a way of increasing organic matter. Winter cover crops have been used for years, primarily to protect soil from erosion. Winter cover crops can also take up much of the nitrogen left over at the end of the growing season. Winter rye has been an old stand by. It can germinate and make quite a bit of growth, even if planted as late as October. Winter rye is efficient at taking up left over nitrogen. It remains green over the winter and resumes growth early in the spring. It adds little organic matter if plowed under in early Spring while still small. If allowed to grow until late may, it can reach three to four feet and contribute a fair amount of organic matter. Unless plowed under while quite small, it can be difficult to break up the clumps of winter rye, making it difficult to seed crops. (http://extension.umass.edu/vegetable/articles/soil-basics-part-iii) TANAMAN PENUTUP TANAH Sumber: journeytoforever.org/farm_library/AD2.pdf….. Diunduh 15/3/2012

  8. SOIL FERTILITY MANAGEMENT Laura van Schöll, Rienke Nieuwenhuis Agromisa Foundation, Wageningen, 2004. Soil fertility and fertilisers The use of animal manure and compost contributes to retaining the level of organic matter in the soil. Chemical fertiliser can be needed to quickly supply a crop with required nutrients. In contrast to organic fertilisers, chemical fertilisers help the plants immediately; organic manures first have to be broken down into nutrients before they can be utilised by the plants. This means that organic material only has an effect in the long term, while chemical fertilisers contribute immediately (within a few days to weeks) to soil fertility. However, chemical fertilisers are depleted by the end of the season or seasons, while organic matter continues to enhance soil fertility as well as the soil structure. Moreover, the presence of organic material ensures that the chemical fertiliser is more efficiently utilised by the crop because it prevents the fertiliser from being leached. Pada tanah-tanah yang miskin bahan organik, aplikasi pupuk kimia buatan harus dibarengi dengan aplikasi bahan organik secukupnya Sumber: ….. Diunduh 15/3/2012

  9. KESUBURAN TANAH DAN BUDIDAYA TANAMAN After an introduction about crop husbandry, organic matter, burning and the local conditions the crop husbandry systems are described in more detail: mulching is a method, in which a layer fresh organic matter is placed on top of the soil; green manuring consists in ploughing under fresh green material; intercropping means growing two or more crops together on the same field; during green fallow periods, species are sown or stimulated that have better qualities then the species that would grow spontaneously in the fallow period; agroforestry comprises all forms of land use in which woody species (trees and shrubs) are grown in combination with other crops. Intercropping is the practice of growing two or more crops in proximity. The most common goal of intercropping is to produce a greater yield on a given piece of land by making use of resources that would otherwise not be utilized by a single crop. Careful planning is required, taking into account the soil, climate, crops, and varieties. It is particularly important not to have crops competing with each other for physical space, nutrients, water, or sunlight. Examples of intercropping strategies are planting a deep-rooted crop with a shallow-rooted crop, or planting a tall crop with a shorter crop that requires partial shade. (http://en.wikipedia.org/wiki/Intercropping) INTERCROPPING Sumber: journeytoforever.org/farm_library/AD2.pdf….. Diunduh 15/3/2012

  10. CROP HUSBANDRY SYSTEM Husbandry means managing resources or caring for animals and crops: Thrifty management of a household is an example of husbandry. The practice of managing a farm, growing crops and breeding animals is an example of husbandry. (sumber; http://www.yourdictionary.com/husbandry) (Husbandry) farming: the practice of cultivating the land or raising stock (sumber: http://nicedefinition.com/Definition/Word/husbandry/husbandry.aspx ) The concept of husbandry, signifying understanding, management and improvement, is widely understood when applied to crops and animals. It is equally applicable to land. Thus, land husbandry can be defined as “the care and management of the land for productive purposes; only through sound land husbandry can the land's productive potential be sustained and enhanced” LAND HUSBANDRY Sumber: lada.virtualcentre.org/.../download.asp?pub….. Diunduh 18/3/2012

  11. Better Land Husbandry Components The intrinsic components to Better Land Husbandry (BLH): Promotion of an integrated and synergistic resource management approach embracing locally appropriate combinations of the following technical options: build-up of soil organic matter and related biological activity to optimum sustainable levels (for improved moisture and nutrient supply and soil structure) through the use of compost, farmyard manure, green manures, surface mulch, enriched fallows, agroforestry, cover crops and/or better crop residue management; integrated plant nutrition management with locally appropriate, and cost effective, combinations of organic/inorganic and on/off-farm sources of plant nutrients (e.g. organic manures, crop residues, rhizobial N-fixation, transfer of nutrients released by weathering in the deeper soil layers to the surface via tree roots and leaf litter, rock phosphate, lime and chemical fertiliser); better crop management, improved seeds of appropriate varieties, improved crop establishment at the beginning of the rains (to increase protective ground cover, thereby reducing water loss and soil erosion), weed management and integrated pest management; better rainwater management to increase infiltration and reduce runoff so as to improve soil moisture conditions within the rooting zone, thereby lessening the risk of moisture stress during dry spells, while reducing erosion; improvement of soil rooting depth and permeability through breaking of a cultivation- induced compacted soil layer (hoe/plough pan) through conservation tillage practices by means of tractor-drawn subsoilers, ox-drawn chisel ploughs, and hand-hoe planting pits/ double dug beds; and/or interplanting of deep rooted perennial crops/trees & shrubs); and reclamation, where appropriate (i.e. if technically feasible and cost effective), of arable land that has been severely degraded by such processes as gullying, loss of topsoil from sheet erosion, soil compaction, acidification and/or salinisation.. B.L.H. Sumber: lada.virtualcentre.org/.../download.asp?pub….. Diunduh 18/3/2012

  12. PENN STATE EXTENSION. College of Agricultural Sciences AGRONOMY GUIDE. CROP AND SOIL MANAGEMENT. Section II. Soil Fertility Management The goal of soil fertility management is to create soil chemical conditions that encourage plant growth and supply required nutrients in the amounts and at the times they are most needed. Liming materials and plant nutrients may be added to the soil in many forms and can be done so in a way that maximizes the economic benefits of nutrients while minimizing any environmental impact. The ways in which crops respond to these applications often are different because some soils have inherent physical limitations to plant growth. Soil testing is the best guide to soil fertility. Plant tissue analysis also may be helpful when used in conjunction with soil testing. Uji Tanah dan Tanaman Sumber: http://extension.psu.edu/agronomy-guide/cm/sec2/sec21….. Diunduh 15/3/2012

  13. A set of soil fertility management practices that necessarily include the use of fertilizer, organic inputs, and improved germplasm, combined with knowledge on how to adapt these practices to local conditions, and aiming to maximize agronomic use efficiency of the applied nutrients and thus crop productivity. All inputs are managed, using sound agronomic principles. ISFM interventions have been developed for maize, sorghum, and cassava-based systems in the major impact zones. Yield increases were over 100%, even as soil fertility status improved. Activities are now directed towards achieving the same successes with riceand banana-based systems. Conservation agricultural practices are also being developed. Sumber: http://www.ciat.cgiar.org/AboutUs/Documents/synthesis_isfm_program.pdf….. Diunduh 15/3/2012

  14. PENGELOLAAN KESUBURAN TANAH • Goals of a Sustainable Soil Fertility Management Program • 1. To sustain high crop productivity and crop quality in food and fiber production • a) Crop productivity, crop quality, and the success of a given operation • 2. To minimize risks to environmental quality and human health associated with agricultural production • Important steps in minimizing human health risks, and on and off-farm impacts • Avoid the use of all synthetically compounded materials; balance inputs of organic matter and mineral inputs to avoid exceeding crop needs • Avoid creating nonpoint source pollution through surface runoff and leaching • Prevent soil erosion and sedimentation of waterways • Close nutrient cycles as much as possible within the field and farm • Close nutrient cycles at multiple scales: watershed, regional and national scales Sumber: http://63.249.122.224/wp-content/uploads/2010/05/unit_1.1_fertility.pdf….. Diunduh 15/3/2012

  15. Components of a Sustainable Soil Fertility Management Program • 1. Improve and maintain physical and biological properties of soil • a) Sustainable agricultural practices used to improve and sustain soil physical and biological properties • Maintaining or building soil organic matter (SOM) levels through inputs of compost and cover cropping • Properly timed tillage • Irrigation • Sound crop rotations, soil amending, and fertilizing techniques all serve to improve the quality of agricultural soils, which in turn affects soil quality and crop performance. Integrated plant nutrient components in the Nepalese farming system http://www.fao.org/docrep/010/ag120e/AG120E10.htm Sumber: http://63.249.122.224/wp-content/uploads/2010/05/unit_1.1_fertility.pdf….. Diunduh 15/3/2012

  16. Components of a Sustainable Soil Fertility Management Program 2. Improve and maintain chemical properties of soil a) Benchmarks of optimal soil chemistry Balanced levels of available plant nutrients (see Unit 1.11, Reading and Interpreting Soil Test Reports) Soil pH ~6.0–7.0 Low salinity levels b) Sustainable agricultural practices used to develop and maintain optimal soil chemical properties Provide a balanced nutrient supply for the crop Conduct soil sampling and periodic monitoring Conduct plant tissue testing Time seasonal nutrient release from organic amendments to correspond with crop requirements: (a) The quality of the organic matter input; and (b) Environmental factors such as soil temperature and moisture Avoid leaving fields bare to avoid wind and water erosion and nutrient leaching Manage irrigation carefully to avoid runoff, erosion, and leaching of soluble nutrients Supply major nutrients primarily through organic matter and mineral soil amendments Allow sufficient time for fresh residue to break down before planting crops Use in-season supplemental fertilizers when necessary http://cropsoil.psu.edu/extension/facts/agronomy-facts-31a Sumber: http://63.249.122.224/wp-content/uploads/2010/05/unit_1.1_fertility.pdf….. Diunduh 15/3/2012

  17. Components of a Sustainable Soil Fertility Management Program 3. Minimize disease/pest susceptibility a) Sustainable agriculture practices used to minimize disease/pest susceptibility in organic farming systems Maintain soil nutrient levels and soil pH within optimal range Build and maintain soil organic matter to promote desirable soil physical properties and supply essential plant nutrients Maintain soil moisture within optimal ranges for plant growth and the avoidance of compaction and erosion Design appropriate rotations to break pest cycles Plant polycultures Use appropriate preventative and active biocontrol practices Polyculture is agriculture using multiple crops in the same space, in imitation of the diversity of natural ecosystems, and avoiding large stands of single crops, or monoculture. It includes crop rotation, multi-cropping, intercropping, companion planting, beneficial weeds, and alley cropping. Polyculture, though it often requires more labor, has several advantages over monoculture: The diversity of crops avoids the susceptibility of monocultures to disease. For example, a study in China reported in Nature showed that planting several varieties of rice in the same field increased yields by 89%, largely because of a dramatic (94%) decrease in the incidence of disease, which made pesticides redundant (Nature 406, 718 - 722 , 17 augt. 2000). The greater variety of crops provides habitat for more species, increasing local biodiversity. This is one example of reconciliation ecology, or accommodating biodiversity within human landscapes. It is also a function of a biological pest control program. (http://en.wikipedia.org/wiki/Polyculture) Sumber: http://63.249.122.224/wp-content/uploads/2010/05/unit_1.1_fertility.pdf….. Diunduh 15/3/2012

  18. Soil Fertility and Soil Quality in Sustainable Farming Systems • KESUBURAN TANAH DAN KUALITAS TANAH • Kualitas Tanah • IndikatorKualitas Tanah • Ketersediaanhara • Ketersediaan air • Promotes good root growth and maintains good habitat for soil organisms • Mencegahdegradasi • Maintains good soil structure to provide adequate aeration and tilth • Good soil structure allows for rapid water infiltration • pH moderat (6.0–7.5) • Tingkat salinitasrendah • Low levels of potentially toxic elements • Kesuburantanahberimbang. • c) Soil fertility: The capacity of a soil to provide nutrients required by plants for growth; one component of soil quality • 2. Soil fertility, plant health, and the resistance and resilience of crop plants to pest and pathogens Concept of Nutrient Availability Soil is a living medium consisting of physical part - called as soil particles, chemical part - consisting of various compounds as well as biological part - consisting of various microbes, vertebrates, invertebrates inhabiting in soil. Unless all these components are kept in harmony, the crop plants would suffer by poor nutrient availability. Nutrients are made available to crop roots through the living media of soil mainly by processes called as Mass flow Cation exchange and anion exchange Diffusion http://www.tutorvista.com/content/biology/biology-iv/food-production/nutrient-availability.php Sumber: http://63.249.122.224/wp-content/uploads/2010/05/unit_1.1_fertility.pdf….. Diunduh 15/3/2012

  19. PENGELOLAAN KESUBURAN TANAH PENGOLAHAN TANAH DALAM PERTANIAN BERKELANJUTAN 1. Services provided by tillage Prepares the ground for seedlings and transplants Provides a range of residue incorporation options Enables the incorporation of amendments Improves soil aeration, and breaks up soil clods to form good seed and root beds Improves water infiltration Increases rate of microbial activity and mineralization Deep tillage can break through compacted layers 2. Disadvantages of tillage Accelerates the rate and extent of long-term declines in soil organic matter May increase sub-soil compaction High energy and labor costs Loss of soil organic matter (SOM) from excessive tillage can lead to crusting of bare soils 3. Advantages of reduced and no-tillage systems Residue cover protects the soil from wind and water erosion Allows for greater moisture retention in rain-fed systems These systems build SOM over a period of years, and reach a higher “steady state” level than tilled systems in the same environment Reduced tillage in agricultural soils creates a greater carbon sink 4. Limitations of reduced and no-till agriculture systems Residue cover lowers soil temperature, which delays seed germination and slows seedling growth and may place growers at an economic disadvantage Weed control is very difficult without use of herbicides Requires specialized equipment to plant through thick layer of residue Increased leaching of nutrients and herbicides into the groundwater has been shown in some Sumber: http://63.249.122.224/wp-content/uploads/2010/05/unit_1.1_fertility.pdf….. Diunduh 15/3/2012

  20. PENGELOLAAN KESUBURAN TANAH Cover Crops dalamPertanianBerkelanjutan 1. Services provided by cover crops a) Cover crops increase nutrient availability The role of legume cover crops in biological N fixation and nutrient budgeting Nutrients are released into the soil solution as the cover crop residues are broken down Cover crops can stimulate microbial activity and increase the breakdown of existing SOM Deep-rooted cover crops are able to recycle nutrients acquired from deeper in the soil profile Grass/cereal cover crops may reduce nutrient losses by capturing mobile nutrients (e.g., nitrate) 2. Influences on the nutrient release from cover crops a) Temperature and moisture conditions b) Placement of the residue Residue on soil surface: Will decompose more slowly due to drying Incorporation into the top 6–8 inches of the soil: Will decompose most rapidly due to high oxygen levels and the presence of large populations of decomposing organisms Below 6–8 inches: Will decompose more slowly due to lower oxygen levels, fewer decomposers c) Composition/“quality” of the cover crop residue The C to N ratio of the cover crop residue and N mineralization: (a) C/N ratios around 22:1 or less = net mineralization of N; (b) C/N ratios above 22:1 = net immobilization of N Optimum stage of development to incorporate cover crops = 75%–100% of full bloom The presence of lignins and tannins in cover crop residue slows decomposition Sumber: http://63.249.122.224/wp-content/uploads/2010/05/unit_1.1_fertility.pdf….. Diunduh 15/3/2012

  21. PENGELOLAAN KESUBURAN TANAH • Cover Crops dalamPertanianBerkelanjutan • 3. The timing of nutrient release, crop demand, and the fate of essential plant nutrients • Managing the timing of nutrient release from cover crops to coincide with crop demand • Leaching: Nutrients (N) can become vulnerable to loss if timing is mismatched • Nutrient deficiencies: If timing is mismatched, nutrient deficiencies (N) may then result • 4. Some effects of cover crops on agricultural soils • Improvements to soil physical properties: Carbon and nutrient cycling through the use of cover crops • The influence of cover crops on disease and pest severity • Rye, triticale, forage rapeseeds, mustards, and oil seed radish are known to suppress certain plant parasitic nematodes and soil borne diseases • Many legumes can actually increase pest populations • c) Weed-suppressive effects of cover crops • i. Competition for light/smothering • ii. Allelopathy • 5. Importance of gathering regional cover crop information A cover crop is a type of plant grown to suppress weeds, help build and improve soil, and control diseases and pests. Cover crops are also called "green manure" and "living mulches." They're called "green manure" because they provide nutrients to the soil much like manure does. And as "living mulches," cover crops prevent soil erosion. Once grown, cover crops are usually mowed and then tilled into the soil. http://smallfarm.about.com/od/glossary/g/Cover-Crop.htm Sumber: http://63.249.122.224/wp-content/uploads/2010/05/unit_1.1_fertility.pdf….. Diunduh 15/3/2012

  22. PENGELOLAAN KESUBURAN TANAH • KOMPOS DAN PUPUK KANDANG • 1. Composts • a) How much compost to apply annually • b) The nutrient contribution of a manure-based compost: ~1N-1P-1K, i.e., balanced • contribution of N-P-K. As nutrient levels in compost vary, it is recommended that • you check with supplier or have a compost nutrient assessment done to confirm • nutrient levels and proportions. • c) Application timing: Nutrient release should ideally coincide with crop demand • Depending on compost quality, may be an inefficient source of N in short term • Release of N may last 6 weeks–several months following incorporation, depending on compost quality and environmental conditions • Need to incorporate into root zone if applying mid season as side dress • d) Compost quality indicators • C:N ratio • CO2 levels • Ammonia levels • Smell • Color • Texture/feel • Temperature • e) Ease and economics of use • f) Labor and/or equipment requirements for on-farm production of compost. • g) National Organic Program standards for on-farm compost production • h) Transportation issues: • Local/regional availability and costs; • Variability in quality Sumber: http://63.249.122.224/wp-content/uploads/2010/05/unit_1.1_fertility.pdf….. Diunduh 15/3/2012

  23. PENGELOLAAN KESUBURAN TANAH Effect of Manure application on carbon budgets in ecosystems http://www.soi.wide.ad.jp/class/20070046/slides/03/32.html The use of fresh and undecomposed manure in agricultural systems: Cropping in soils with fresh and/or undecomposed manures may result in nitrogen “burns” (due to high ammonium levels) and nitrate depression/net immobilization, respectively Restrictions on the use of manure under National Organic Standards Variations in the nutrient profiles of animal manures: The nutrient profile of fresh manures range from approximately .75-.75-.75 (horse manure) to 2-2-2 (poultry manure). Handling and storage of animal manures for the conservation of nutrients: Fresh animal manures should be temporarily stored and protected from sun and rain by covering with tarps Food safety issue: NOP guidelines designed to prevent contamination by E. coli and other disease-causing organisms PUPUK KANDANG Sumber: http://63.249.122.224/wp-content/uploads/2010/05/unit_1.1_fertility.pdf….. Diunduh 15/3/2012

  24. PENGELOLAAN KESUBURAN TANAH Soil Amendments and Supplemental Fertilizers 1. Organic amendments a) OMRI/NOP-certified materials in certified organic farming systems b) Nutrient budgeting 2. Supplemental fertilizers: When used 3. Soil fertility management and nutrient budgets: Balancing nutrient inputs with nutrient outputs each year Inputs > outputs = accumulation. Potential risk of excess nutrients creating nonpoint source pollution through leaching and run off, and enhancing disease and pest incidence. Inputs < outputs = soil depletion. Potential risk of plant nutrient deficiencies and stress, reduced yield, and increased susceptibility to pest and pathogens. Goal: Balance inputs and outputs once you have achieved desired/optimal nutrient levels in the soil. Example of inputs factored into budget for nitrogen Inputs = imported fertilizers and amendments + atmospheric deposition + N fixation through cover crops Outputs = N exported in crop harvest + N lost through leaching, erosion, and denitrification Calculating nutrient budgets: See Unit 1.11, Reading and Interpreting Soil Test Reports 4. Application of nutrient budgets in assessing the health of larger-scale units: Watersheds, regions.. Example of accumulation and depletion, e.g., the impact of high densities of confinement animal production facilities. Sumber: http://63.249.122.224/wp-content/uploads/2010/05/unit_1.1_fertility.pdf….. Diunduh 15/3/2012

  25. PENGELOLAAN KESUBURAN TANAH PERGILIRAN TANAMAN 1. Crop rotation 2. Rotation considerations a) Try to avoid rotation of crop species that share similar pests and diseases. Intersperse with different crops to break pest and disease cycles. Example: Solanaceae rotation b) Rotation of crops to maximize use of nutrient inputs and distribute nutrient demand placed on the soil. Examples of multi-year crop rotations (Coleman 1995) c) Fallow periods and perennial cover crop rotations Pola pergiliran tanaman sayuran dalam periode lima tahun http://www.howto.co.uk/learning/allotments/crop_rotation/ Sumber: http://63.249.122.224/wp-content/uploads/2010/05/unit_1.1_fertility.pdf….. Diunduh 15/3/2012

  26. DINAMIKA HARA TANAH Mempertahankan jumlah optimum unsur hara hanya dapat terlaksana dengan menciptakan keseimbangan yang baik antara penambahan dan kehilangannya Benefits of Organic Matter  Reduces compaction and bulk density Provides a food source for microorganisms Increases activities of earthworms and other soil critters Benefits of Organic Matter  Increases soil CEC Stabilizes nutrients Builds soil friability and tilth Reduces soil splash Carbon Sequestration C cycling in agroecosystems has a significant impact at the global scale because agriculture occupies approximately 11% of the land surface area of the earth. Carbon sequestration is the capture of carbon dioxide (CO2) and may refer specifically to: "The process of removing carbon from the atmosphere and depositing it in a reservoir.“ When carried out deliberately, this may also be referred to as carbon dioxide removal, which is a form of geoengineering. The process of carbon capture and storage, where carbon dioxide is removed from flue gases, such as on power stations, before being stored in underground reservoirs. Natural biogeochemical cycling of carbon between the atmosphere and reservoirs, such as by chemical weathering of rocks. (http://en.wikipedia.org/wiki/Carbon_sequestration)

  27. PENTINGNYA PUPUK DAN PEMUPUKAN Fertilizer is any organic or inorganic material of natural or synthetic origin (other than liming materials) that is added to a soil to supply one or more plant nutrients essential to the growth of plants. A recent assessment found that about 40 to 60% of crop yields are attributable to commercial fertilizer use. They are essential for high-yield harvest. (http://en.wikipedia.org/wiki/Fertilizer) Balanced nutrition is important in obtaining maximum yields. The most usual limitations concern nitrogen, phosphorus and potassium, followed by sulphur. Sumber: http://www.sunkarresources.com/en/pages/Importance_of__fertilizers ….. Diunduh 17/3/2012

  28. KETERSEDIAAN UNSUR HARA DAN pH Nutrient availability and soil pH Some generalizations can be made regarding the availability of nutrients to plants in relation to soil pH. Deficiencies of zinc, manganese, and iron are more common on alkalines soils while deficiencies of molybdenum, calcium, and magnesium occur more commonly on acid soils. For other nutrients such as potassium and sulfur, there is little association between soil pH and availability to plants. Toxicities of aluminum and manganesse occur almost exclusively on acid soils. (http://wheatdoctor.cimmyt.org/en/nutrient-problems/list/176?task=view) Chart of the Effect of Soil pH on Nutrient Availability Sumber: http://www.avocadosource.com/tools/fertcalc_files/ph.htm….. Diunduh 15/3/2012

  29. Cation Exchange Capacity – Everything You Want to Know and Much More James J. Camberato Clemson University, Crop and Soil Environmental Science RINGKASAN Cation exchange capacity (CEC) is the amount of negative charge in soil that is available to bind positively charged ions (cations). Essential plant nutrients, K+, Ca2+, Mg2+, and NH4 + and detrimental elements, Na+, H+, and Al+3 are cations. Cation exchange capacity buffers fluctuations in nutrient availability and soil pH. Clay and organic matter are the main sources of CEC. The CEC of most native soils in the Carolinas and sand-based sports fields is low because they are low in clay and organic matter. What little CEC exists in these soils is pH dependent, thus it is beneficial to maintain soil pH near 6.5 for optimum levels. Adding calcined clay, diatomaceous earth, or zeolite/clinoptilolite increases CEC, but the benefits of adding these materials in lieu of peat or organic matter maintenance are not well established. Cation exchange capacity is estimated and reported by most soil testing laboratories. Estimates are reasonably accurate unless the soil has been heavily fertilized or amended just prior to sampling or an acid extractant was used on a soil containing precipitated calcium carbonate. Base saturation, the quantity of CEC occupied by one or more of the basic cations, is useful for managing detrimental levels of soil Na+ and Mg2+ availability. Sumber: http://www.jbhs.ccs.k12.nc.us/Facultyandstaff/withers/Supplemental%20Notes%20For%20APES/cation%20exchange%20capacity.pdf ….. Diunduh 15/3/2012

  30. Organic matter, nutrient contents and cation exchange capacity in fine fractions from semiarid calcareous soils F. Caravaca ), A. Lax, J. Albaladejo. Geoderma 93 1999. 161–176 ABSTRACT Soil erosion, which is a widespread problem in semiarid areas, may lead to a decline in soil productivity since the finest and most fertile soil particles are those which are generally removed. Our objective was to determine the distribution of soil organic matter, phosphorus, potassium and cation exchange capacity within the fine fractions -2 mm and 2–20 mm. of the soil. Samples were taken from the top 20 cm of 14 cultivated soils and six forest soils. The organo-mineral size fractions from soil samples were isolated without chemical pretreatment by ultrasonic dispersion in water followed by sedimentation–syphonation. The distribution of organic matter within size fractions varied with land use. The cultivated soils had a greater percentage on average, about 30%. of total soil C in the -2 mm fraction than the soils under natural vegetation on average, about 18%., in which the total soil C was associated with the 2–20 mm fraction to a greater extent than in cultivated soils. The distribution of the soil N between the clay and fine silt size fractions followed a similar pattern to that shown by soil C. The CrN ratio became smaller as particle size decreased. The higher CrN ratio obtained for the 2–20 mm fraction for both forest and cultivated soils suggests the presence of less decomposed organic matter, while the organic matter associated with the -2 mm fraction can be considered to be more humified. The cation exchange capacity of whole soil and organo-mineral fractions were closely correlated with their respective C contents. The clay-size fraction had the highest CEC, which was related to its mineralogical composition. The data confirm that the proportion of soil organic matter depends on the stabilizing capacity of the different size fractions, both the clay and fine silt size fractions playing an important role in semiarid soils. To the detriment of the soil’s organic matter content these fractions are easily eroded in soils under arid and semiarid conditions, which may render them unsuitable for agricultural purposes.. Sumber: http://eusoils.jrc.ec.europa.eu/projects/scape/uploads/90/Caravace_Lax_Albaladejo.pdf….. Diunduh 15/3/2012

  31. POKOK-POKOK PENGELOLAAN KESUBURAN TANAH. • Suplai nitrogen dari: • SisaTanamanTanamanbiasa • PupukkandangTanaman legume • Hujan & irigasiPupukhijau • Pupuk nitrogen Kompos 2. Penambahan bahan organik melalui: Sisa tanaman legume dan non legume Pupuk kandang Pupuk hijau 3. Penambahan kapur bila diperlukan Batu kapur kalsit atau dolomit yg biasa dilakukan 4. Penambahan fosfat: Pupuk superfosfat, atau Pupuk lainnya 5. Penambahan kalium tersedia: Pupuk kandang Sisa tanaman Pupuk Kalium 6. Kekurangan belerang diatasi dg: Belerang, gipsum, superfosfat, Amonium sulfat, Senyawa belerangdalam air hujan 7. Penambahan unsur mikro: Sebagai garam terpisah atau campuran

  32. THE FATE OF PHOSPHATE FERTILISERS IN SOIL I.S. Cornforth (Department of Soil Science, Lincoln University) Phosphorus participates in many of the reactions that keep plants and animals alive, and is thus essential for all living organisms. Phosphorous is found in two different forms in soil: inorganic and organic. Inorganic phosphorus The main inorganic forms of phosphorus in soil are H2PO4- and HPO42-. This is the form in which phsophorus is used by plants. However, these ions can also absorb onto the surface (or adsorb into) solid matter in the soil. This phosphorus is then unavailable to plants. Organic phosphorus Between 50 and 80% of phosphorus in soil is organic phosphorus. This comes from the breakdown of dead plants etc., as phosphorus is found in cell membranes and DNA in living organisms. Phosphorus is thus naturally available in the soil. However, there isn't usually enough available for plants to grow well. Phosphorus levels are reduced by animals eating the plants then dying elsewhere so that the phosphorus is removed, and also by phosphorus being adsorbed into soil particles or washed away by excess rain. For this reason phosphate fertilisers are widely used. The ways in which this influences phosphate cycling in the soil are discussed in more detail in the following article. As a particle of fertilizer comes in contact with the soil, moisture from the soil will begin dissolving the particle. Dissolving of the fertilizer increases the soluble phosphate in the soil solution around the particle and allows the dissolved phosphate to move a short distance away from the fertilizer particle. Movement is slow but may be increased by rainfall or irrigation water flowing through the soil. As phosphate ions in solution slowly migrate away from the fertilizer particle, most of the phosphate will react with the minerals within the soil. Phosphate ions generally react by adsorbing to soil particles or by combining with elements in the soil such as calcium (Ca), magnesium (Mg), aluminum (Al), and iron (Fe), and forming compounds that are solids. The adsorbed phosphate and the newly formed solids are relatively available to meet crop needs. (http://www.extension.umn.edu/distribution/cropsystems/DC6795.html) The availability of phosphorus is affected by soil pH. Sumber: http://nzic.org.nz/ChemProcesses/soils/2D.pdf….. Diunduh 15/3/2012

  33. THE FATE OF PHOSPHATE FERTILISERS IN SOIL I.S. Cornforth (Department of Soil Science, Lincoln University) Examples of phosphate adsorption mechanisms Sumber: http://nzic.org.nz/ChemProcesses/soils/2D.pdf….. Diunduh 15/3/2012

  34. THE FATE OF PHOSPHATE FERTILISERS IN SOIL I.S. Cornforth (Department of Soil Science, Lincoln University) The absorption of adsorbed P into soil minerals (a) and the subsequent occlusion of adsorbed P (b) Sumber: http://nzic.org.nz/ChemProcesses/soils/2D.pdf….. Diunduh 15/3/2012

  35. THE DYNAMICS OF POTASSIUM (K) IN REPRESENTATIVE SOIL SERIES OF GHANA D. O. Yawson, P. K. Kwakye, F. A. Armahand K.A. Frimpong. ARPN Journal of Agricultural and Biological Science VOL. 6, NO. 1, JANUARY 2011 ABSTRACT The immediate supply of K by soils to growing plants derives mainly from the K that is labile whereas the long term K nutrition of plants depends on the non-labile K. The dynamic relationship between these forms of K constitutes the dynamics of K in soils. Most Ghanaian farmers grow root and tuberous crops which have high K requirements. Knowledge of K dynamics in soils is therefore essential for K management to sustain crop production and management of agro-ecological environments in Ghana. Quantity-Intensity isotherms provide a better overview of K dynamics in soils. Therefore, Quantity/Intensity (Q/I) curves were used in this study to evaluate the dynamics of K in ten soil series representing the major agro-ecological zones of Ghana. K dynamics in the soils were found to be influenced by some soil properties. Significant correlations were found between soil properties and Q/I parameters; and among equilibrium solution parameters and Q/I parameters. There was no significant variation among the mean quantity (±ΔK) values of the soils. The savannah soils had higher non-specific K, K-potential, and potential buffering capacity (PBCK) than the forest soils; and the Akuse series had the highest values for these parameters. However, the forest soils had higher K-intensity. Therefore, the forest soils will require frequent and split K applications since they have lower capacity to maintain long-term supply of K. However, the savannah soils will require less frequent but higher K fertilization to satisfy the exchangeable pool and immediate plant nutrition requirement Sumber: http://www.arpnjournals.com/jabs/research_papers/rp_2011/jabs_0111_233.pdf….. Diunduh 15/3/2012

  36. SOIL FACTORS AFFECTING MAGNESIUM AVAILABILITY IN PLANT-ANIMAL SYSTEMS: A REVIEW I H. F. Mayland and S. R. Wilkinson. J. Anita Sei. 1989. 67:3437-3444 ABSYRAOT Soils provide the support, water and most of the nutrient elements, including Mg, needed for plant growth. Magnesium uptake by plants depends largely on the amount, concentration and activity of Mg in the soil solution and the capacity of the soil to replenish Mg in the soil solution. The availability of Mg depends on the activity or proportion of Mg relative to soluble and exchangeable amounts of K, Ca, Na, AI and Mn. In humid regions, Mg losses from leaching are often greatest from agroecosystems receiving heavy N fertilization. Cool-season grasses produce nearly maximum growth at herbage concentrations of 1 to 1.5 g Mg/kg, 25 g K/kg and 30 g N/kg of dry matter. At these concentrations of N and K, herbage should contain about 2.5 g Mg/kg to avoid inducing hypomagnesemic grass tetany in ruminants. To increase herbage Mg concentration to this level often requires, except on sandy soils, an uneconomically large addition of Mg fertilizer. Adjusting soil conditions to produce grasses with a low-tetany potential may not always be possible physically. The risk of tetany can be reduced by a judicious program of well-timed N, K and Mg fertilizer applications. However, direct Mg supplementation of grazing ruminants is considered more cost-effective than is Mg fertilization to prevent grass tetany. Sumber: http://www.animal-science.org/content/67/12/3437.full.pdf ….. Diunduh 15/3/2012

  37. Effects of Potassium Fertilization on Soil Potassium Distribution and Balance in Pistachio Orchards David Qiupeng Zeng, Patrick H. Brown, and Brent A. Holtz Better Crops/Vol. 83 (1999, No. 4) Potassium distribution in the soil profile is characterized by decreasing soil K content with depth. Potassium fertilization significantly increased soil K content throughout the 0 to 30 inch soil profile, even though the movement of surface-applied K in the soil profile was slow. More K was accumulated in the fruit and leaves in pistachio trees treated with K. Soil K balance data showed that without K fertilization, soil available K was rapidly depleted. To accurately diagnose soil K deficiency and to determine K fertilization requirements in pistachio, it is important to examine K status in the irrigated soil profile. Fertilizer and Management Practices Increased use of nitrogen (N) and other limiting nutrients. When adequate K is available, addition of N and/or phosphorus (P) greatly increases K uptake, as yields are increased. Usually the uptake of K by crops closely parallels N uptake and may be greater. So, as limiting nutrients are added, the demands on soil K increase. Applications of K in fertilizers, manures or crop residues. The major way to increase K availability is to apply adequate amounts. Potassium is readily available from all these sources, provided they are located where roots can absorb the K. Placement of K. Broadcast plow-down applications of K are more available than surface applied disked-in K. Row K at moderate rates and soil test levels is usually twice as available to corn as similar amounts broadcast. Deep placement or drip irrigation helps move K down. Gypsum applied with K also helps move K down in very fine textured soils. Conservation tillage limits availability of surface applied K. Soil K levels should be built to high levels before shifting to minimum or conservation tillage. This improves K distribution within the plow layer. In many fine textured soils, surface applied K moves very little in the soil and has low availability, particularly under dryland conditions. Drainage increases K availability. Draining soils of excess moisture helps many soils warm up and improves the soil aeration. This improves the availability of soil K. Weed and insect control. Controlling weeds and insects reduces competition for moisture and nutrients, so that the crop being produced has relatively more K available. (http://www.ipni.net/ppiweb/bcrops.nsf/$webindex/726438DEC39EDF01852568F000677EB8/$file/98-3p14.pdf) Sumber: http://ucanr.org/sites/nm/files/76664.pdf….. Diunduh 15/3/2012

  38. Effects of Potassium Fertilization on Soil Potassium Distribution and Balance in Pistachio Orchards David Qiupeng Zeng, Patrick H. Brown, and Brent A. Holtz Better Crops/Vol. 83 (1999, No. 4) Potassium distribution in the soil profile after three years of K fertilization at various rates in the Madera orchard. Each value is the average of five repli cates ± standard error. Sumber: http://ucanr.org/sites/nm/files/76664.pdf….. Diunduh 15/3/2012

  39. MENGATASI KEKURANGAN NITROGEN The term “Agronomic Optimum N Rate” or AONR defines the N rate that will produce maximum grain yield, regardless of cost. The term “Economic Optimum N Rate” or EONR defines the N rate that will result in the maximum dollar return to N. The EONR is usually less than the AONR, will usually decrease as N prices increase, will usually increase as grain prices increase, or may remain the same if the ratio between nitrogen cost and grain price (N:G) remains the same. (http://www.agry.purdue.edu/Ext/corn/news/timeless/nitrogenmgmt.pdf) Penambahan & Kehilangan N-tersedia Pengikatan Nitrogen Pupuk Buatan Simbiotik Non-Simbiotik Sisa tanaman Pupuk Kandang N-tersedia dlm tanah Atmosfer Bahan Organik Panen Tanaman Hilang Erosi Hilang Pencucian

  40. The fate of nitrogen from legume and fertilizer sources in soils successively cropped with wheat under field conditions J.N. Ladd, M. Amato Soil Biology and Biochemistry. Volume 18, Issue 4, 1986, Pages 417–425 Abstract Using 15N-labelled legume material (Medicago littoralis) and fertilizers (urea, (NH4)2SO4, KNO3), a direct comparison has been made of the fate of nitrogen from these sources and their residues, in soils sown with two successive wheat crops. The availability of N from each source to both crops is discussed in terms of the release, movement and immobilization of N in the soil profiles. For fertilizer 15N, uptake by crops, distribution as inorganic 15N in soil profiles, total recovery and percentage recovery in organic residues in soil were not significantly influenced by the form of fertilizer applied. For both legume and fertilizer 15N, uptake by both crops was directly related to input; and uptake by the second crop was directly related to the amounts of 15N residual in soil after the first crop. About 17% of applied legume N was taken up by the tops of the first wheat crop, and, at the time of sowing of the second crop, about 62% remained as organic residues; total recovery in crop and soil averaged 84%. By contrast, about 46% of applied fertilizer N was taken up by crop 1, and at sowing in the following year 29% was present as organic residues, and total recovery in soil plus crop averaged 80% The availabilities of N from both legume and fertilizer residues to a second wheat crop declined markedly but continued to differ significantly (P < 0.01) from each other. Expressed as percentages of total residual 15N present in soils at sowing, the second crop took up about 6% of legume-derived N and about 9% of fertilizer-derived N. Fertilizer N directly contributed 5% and 0.5% respectively of the N of first and second wheat crops, per 10kg of fertilizer N applied ha−1. Under the same conditions, legume N directly contributed about 2% and 1% respectively of the N of successive crops, per 10 kg of legume N applied ha−1. The proportions of grain N derived from the applied sources were higher than those of straw N. For both legume and fertilizer 15N, the amounts of inorganic 15N present in soil profiles at sowing in successive years were directly related to 15N inputs. A small but statistically-significant departure from linearity was observed for inorganic 15N at sowing of crop 2 when related to total recoveries of 15N in soils at that time; the higher the amount of 15N recovered, the greater the proportion present as inorganic 15N in the soil profile. The respective contributions of legume and fertilizer N to the total inorganic N pool in soil at sowing declined each year, but were similar to their contributions to the N of the following wheat crop. Concentrations of inorganic N and 15N in soil profiles varied each year but their patterns of distribution in cropped soils were not influenced by the nature and amount of the initial amendments. The 15N atom% enrichments of the inorganic N at sowing in the cropped soils were relatively uniform throughout the profile. Sumber: ….. Diunduh 15/3/2012. http://www.sciencedirect.com/science/article/pii/0038071786900489

  41. Soil & Tillage Research 33 (1995) 197-213 Traffic and residue management systems: effects on fate of fertilizer N in corn H.A. Torbert , D.W. Reeves. ABSTRACT Soil compaction has been recognized as a problem limiting crop production, especially in the Southern Coastal Plain of the USA. Development of tillage and residue management systems is needed to alleviate soil compaction problems in these soils. Fertilizer nitrogen (N) management is also an important factor in these management systems. In 1988, a study was initiated with a wide-frame (6.3 m) vehicle to determine the interactive effects of traffic, deep tillage, and surface residue management on the fate of fertilizer N applied to corn ( Zea mays L.) grown on a Norfork loamy sand (fine-loamy, siliceous, Thermic, Typic Kandiudults). Corn was planted into a winter cover crop of 'Tibbee' crimson clover ( Trifolium incarnatum L ). Treatments included: traffic (conventional equipment or no traffic): deep tillage (no deep tillage, annual in-row subsoiling, or one-time only complete disruption); residue management (no surface tillage or disk and field cultivation). The one-time only complete disruption was accomplished by subsoiling at a depth of 43 cm on 25 cm centers in spring 1988. In 1990-1991, fertilizer applications were made as 15Ndepleted NH4NO3 to microplots inside each treatment plot. The 1990 and 1991 data are reported here. In 1990 an extreme drought resulted in an average grain yield of 1.8 Mg grain ha-1. whereas abundant rainfall in 1991 resulted in 9.4 Mg grain ha-1. Deep tillage Increased corn dry matter production in both years. In 1991, grain yields indicated that corn was susceptible to recompaction of soil owning to traffic when residues were incorporated with surface tillage. In the dry year, plant N uptake was increased 27% with deep tillage and decreased 10% with traffic. In the wet year, a surface tillage x deep tillage x traffic interaction was observed for total N uptake, fertilizer N uptake, and total fertilizer N recovery in the plant-soil system. When combined with traffic, plant N uptake was reduced with the highest intensity tillage treatment (135 kg N ha-1) because of rootrrestricting soil compaction. and with the lowest intensity tillage treatment (129 kg N ha-1) because of increased N losses. In these soils, leaving residues on the soil surface can reduce the detrimental effect of traffic on corn production, but if no surface tillage is performed, deep tillage is needed.

  42. SOIL ORGANIC MATTER AS A FUNCTION OF NITROGEN FERTILIZATION IN CROP SUCCESSIONS Renato Yagi; Manoel Evaristo Ferreira; Mara Cristina Pessôa da Cruz; José Carlos Barbosa; Luiz Alberto Navarro de Araújo. Sci. Agric. (Piracicaba, Braz.), v.62, n.4, p.374-380, July/Aug. 2005 ABSTRACT The interdependence between the C and N cycles is reflected by the levels of soil organic matter (SOM). SOM and organic C levels in water soluble (C-WS) humic acids (C-HA), fulvic acids (C-FA), and humin fractions (C-H) were evaluated through the classic chemical fractionation method in samples of a Rhodic Eutrudox from a randomized blocks experimental design, with split-split-plots using five nitrogen sidedressing levels for corn (0; 60; 120; 180; and 240 kg ha-1 N) as the main treatment, two crop sequences (corn-corn and soybean-corn) as the secondary treatment, and two sampling depths (0 to 0.2 and 0.2 to 0.4 m) as a sub-subtreatment. Nitrogen fertilization did not affect SOM levels, but favored the synthesis of substances in the C-HA fraction. There was a quadratic effect of N rates on the C-WS and C-FA levels in the corn-corn succession. The soybean-corn succession resulted in larger SOM and organic C levels in the C-H fraction . N in soil organic matter – How much is released? It is not uncommon for some to use a general rule of thumb of about 1 to 2% release of N in soil organic matter, during the spring through summer growing season each year.The release rate varies with soil texture or CEC, soil pH, soil microbial population, the prevailing temperature and moisture, as well as with any soil disturbance by tillage. The range of N released (mineralized) by soil microbes may be approximately 10 to 80 lb/A each growing season, or more. Obviously, more N is released during warm, moist conditions as opposed to those that are cool and dry. With such a broad range, it is no surprise that there have been many attempts to develop more reliable measures of “potentially available soil N”, and in some regions, soil N tests have met with some calibration and field validation success. Often, these “potentially available soil N” tests require sampling beyond the typical 0 to 6 in. depth, and may require sampling to 2 or 3 ft. deep. (Sumber: http://www.agprofessional.com/resource-centers/crop-fertility/nitrogen/news/N-in-soil-organic-matter--How-much-is-released-into-fields-136615318.html ….. Diunduh 21/3/2012 ) Sumber: http://www.scielo.br/pdf/sa/v62n4/25090.pdf….. Diunduh 15/3/2012

  43. MEMPERTAHANKAN BAHAN ORGANIK TANAH Carbon Inputs to Soil  Crop residues Cover crops Compost , and Manures Carbon SubstrateThe majority of C enters the soil in the form of complex organic matter containing highly reduced, polymeric substances. During decomposition, energy is obtained from oxidation of the C-H bonds in the organic material. Soil Carbon Equilibrium Input primarily as plant products Output mediated by activity of decomposers It is common that from 40 to 60% of the C taken up by microorganisms is immediately released as CO2. Managing soil carbon Natural variations in SOM occur as a result of climate, organisms, parent material, time and relief. The greatest contemporary influence has been that of humans; for example, historical SOM in Australian agricultural soils may have been twice the present range that is typically from 1.6 to 4.6 per cent. It has long been encouraged that farmers adjust practices to maintain or increase the organic component in the soil—on one hand, practices that hasten oxidation of carbon, such as burning crop stubbles or over-cultivation are discouraged; on the other hand, incorporation of organic material, such as manuring has been encouraged. Increasing soil carbon is not a straightforward matter—it is made complex by the relative activity of soil biota, which can consume and release carbon and are made more active by the addition of nitrogen fertilizers. (http://en.wikipedia.org/wiki/Soil_carbon)

  44. Soil Quality Technical Note No. 5 Managing Soil Organic Matter The Key to Air and Water Quality USDA Technical Note No. 5 October 2003 Apply practices that enhance soil organic matter • Diverse, high biomass crop rotations • Cover crops • Reduced tillage • Rotational grazing Organic matter dynamics change • Increased surface residue forms a physical barrier to wind and water erosion. • Higher residue rotations and cover crops contribute more organic matter and nutrients to the soil. • Less soil disturbance means lower organic matter losses. Soil properties change • Surface structure becomes more stable and less prone to crusting and erosion. • Water infiltration increases and runoff decreases when soil structure improves. • Soil organic matter holds 10 to 1,000 times more water and nutrients than the same amount of soil minerals. • Beneficial soil organisms become more numerous and active with diverse crop rotations and higher organic matter levels. Sumber: http://soils.usda.gov/sqi/concepts/soil_organic_matter/files/sq_tn_5.pdf ….. Diunduh 15/3/2012

  45. Oklahoma Cooperative Extension Fact Sheets are also available on our website at: http://osufacts.okstate.edu Building Soil Organic Matter for a Sustainable Organic Crop Production Strategies for Building Soil Organic Matter The methods used for building SOM depend on several factors. One factor is the goal of the practice. Is the goal simply to supply nutrients or to supply both nutrients and build OM in the soil? This question refers to whether a producer should engage in supplying nutrients to make sure higher yield is achieved in the short-term or to consider both yield and conditioning the soil for optimum long-term production. Another factor that affects the strategy is the type of organic enterprise. A producer needs to answer whether they are interested in: • A livestock-crop mixed organic production system • Perennial or annual agronomic crops • Fruits or vegetables • A mixed cropping system It is also important to know the soil type and problems specific to that soil. What is the physical and chemical composition of the soil? For soils rich in nutrients, but difficult to cultivate due to drainage problems, for example, raising the SOM level is recommended. Some soils are low in available nutrients; the strategy should be to supply nutrients as well as build SOM. Similarly, the nature of existing soil problems, such as low or very high pH and salt problems, must be taken into consideration. There are two strategies to build and maintain SOM for organic or, for that matter, any agricultural production system: reduce SOM losses and add organic material. Sumber: … http://pods.dasnr.okstate.edu/docushare/dsweb/Get/Document-6125/PSS-2257web.pdf.. Diunduh 15/3/2012

  46. Oklahoma Cooperative Extension Fact Sheets are also available on our website at: http://osufacts.okstate.edu Building Soil Organic Matter for a Sustainable Organic Crop Production APLIKASI BAHAN ORGANIK KE TANAH There are wide ranges of options that an organic producer can use to add OM to the soil. Organic materials are highly variable in mineralization pattern, nutrient content, and availability. That is why it is important to set a goal and develop a best management plan for a given field. Cover crops, green manure, residue and live mulch, animal waste, compost, uncomposted yard debris, and packaged organic fertilizers are some of the major materials for building SOM. If a producer is planning a certified organic enterprise, it is important to know the allowed and non-allowed organic materials and their sources by national and state organic program rules and regulations. Schematic illustration of the pools and fluxes included in MAGIC for use in simulating the dynamics of organic and inorganic nitrogen in soils (sumber: http://www.macaulay.ac.uk/recover/magic.htm ...,, DIUNDUH 21/3/2012) Sumber: … http://pods.dasnr.okstate.edu/docushare/dsweb/Get/Document-6125/PSS-2257web.pdf.. Diunduh 15/3/2012

  47. Oklahoma Cooperative Extension Fact Sheets are also available on our website at: http://osufacts.okstate.edu Building Soil Organic Matter for a Sustainable Organic Crop Production TANAMAN PENUTUP TANAH DAN PUPUK HIJAU A cover crop is defined as any crop that is planted in a field after or prior to harvest of the major crop to cover the field until the next main crop is planted. A green manure crop is the crop grown on a field and then turned under when still green before the main crop is sown largely to supply nutrients, but also to contribute to the addition of OM. Cover and green manure crops serve four purposes: add OM, supply nutrients, prevent erosion, and prevent leaching by scavenging plant nutrients such as NO3— which otherwise may be leached into ground water. The contribution of cover and green manure crops to build SOM depends on the C:N ratio of the crops. There are four types of cover or green manure crops. Schematic representation of the factors concerning in tree – cover crop system above- and belowground. The tree – cover crop system concerns many factors above- and belowground. These can have significant effects on major processes in agricultural ecosystems and positively influence the soil and environmental quality in a long-term (sumber: http://herkules.oulu.fi/isbn9514267184/html/x154.html…… diunduh 21/3/2012) Sumber: … http://pods.dasnr.okstate.edu/docushare/dsweb/Get/Document-6125/PSS-2257web.pdf.. Diunduh 15/3/2012

  48. Oklahoma Cooperative Extension Fact Sheets are also available on our website at: http://osufacts.okstate.edu Building Soil Organic Matter for a Sustainable Organic Crop Production Maintaining and Monitoring Soil Organic Matter Once an acceptable level of SOM (about 3.5 to 4.0 percent) is obtained, it is desirable to maintain it. As a rule of thumb returning about two to three tons of organic material per year per acre would maintain an acceptable SOM level. Indicators used to monitor the status of soil organic matter in organic production. Sumber: … http://pods.dasnr.okstate.edu/docushare/dsweb/Get/Document-6125/PSS-2257web.pdf.. Diunduh 15/3/2012

  49. Microbial biomass – a significant source for soil organic matter Matthias Kaestner and Anja Miltner Geophysical Research Abstracts Vol. 13, EGU2011-3261, 2011 ABSTRACT The formation of soil organic matter (SOM) has long been a dominating topic in soil science because the amount and composition of SOM determines soil quality but the processes are still not yet really understood. However, proper management of soil organic matter (SOM) is needed for maintaining soil fertility and for mitigation of the global increase of the atmospheric CO2 concentration. It needs to be based on knowledge about the sources, the spatial organisation and the stabilisation processes of SOM. On the molecular level, the degraded plant-derived organic material in soil is considered to be self-assembled and arranged to macromolecular complexes. Both easily degradable and refractory compounds are stabilised in these aggregates. In addition, the so-called humic substances were regarded for a long time as a novel category of cross-linked organic materials. Recently, microbial biomass residues have been identified as a significant source for SOM . We incubated 13C-labelled bacterial cells in an agricultural soil and traced the fate of the 13C label of bacterial biomass in soil by isotopic analysis. In this study, we summarise the mass balance data and visualise the microbial biomass and its residues by scanning electron microscopy (SEM). Our results indicate that a high percentage of the biomass-derived carbon remains in soil, mainly in the non-living part of SOM after extended incubation. The SEM micrographs only rarely show intact cells. Instead, organic patchy fragments of 200-500 nm size are abundant. These fragments are associated with all stages of cell envelope decay and fragmentation. Similar fragments develop on initially clean and sterile in situ microcosms during exposure in groundwater providing evidence for their microbial origin. Microbial cell envelope fragments thus contribute significantly to SOM formation. The results provide a simple explanation for the development of the small, nano-scale patchy organic materials observed in soil electron micrographs. They suggest that microstructures of microbial cells and of small plant debris provide the molecular architecture of SOM adsorbed to particle surfaces. This origin and macromolecular architecture of SOM is consistent with most observations on SOM, e.g. the abundance of microbial-derived biomarkers, the low C/N ratio, the water repellency and the stabilisation of microbial biomass . The specific molecular architecture determines carbon mineralisation and balances as well as the fate of pesticides and environmental contaminants. Sumber: http://meetingorganizer.copernicus.org/EGU2011/EGU2011-3261.pdf ….. Diunduh 17/3/2012

  50. . Effect of cover crop management on soil organic matter Guangwei Ding, Xiaobing Liu, Stephen Herbert, Jeffrey Novak, Dula Amarasiriwardena, Baoshan Xing. Geoderma. Volume 130, Issues 3–4, February 2006, Pages 229–239. Abstract Characterization of soil organic matter (SOM) is important for determining the overall quality of soils, and cover crop system may change SOM characteristics. The purpose of this study was to examine the effect of cover crops on the chemical and structural composition of SOM. We isolated humic substances (HS) from soils with the following cover crop treatments: (a) vetch (Vicia Villosa Roth.)/rye (Sesale cereale L.), (b) rye alone, and (c) check (no cover crops) that were treated with various nitrogen (N) fertilizer rates. CPMAS-TOSS (cross-polarization magic-angle-spinning and total sideband suppression) 13C NMR results indicated that humic acids (HA) from soils under rye only were more aromatic and less aliphatic in character than the other two cover crop systems without fertilizer N treatment. Based on the DRIFT (diffuse reflectance Fourier transform infrared) spectra peak O/R ratios, the intensities of oxygen-containing functional groups to aliphatic and aromatic (referred to as recalcitrant) groups, the highest ratio was found in the HA from the vetch/rye system with fertilizer N. The lowest ratio occurred at the vetch/rye system without fertilizer N treatment. The O/R ratio of fulvic acids (FA) can be ranked as: vetch/rye without fertilizer>vetch/rye with fertilizer>no cover crop without fertilizer>rye alone (with or without fertilizer) soils. Both organic carbon (OC) and light fraction (LF) contents were higher in soils under cover crop treatments with and without fertilizer N than soils with no cover crop. These chemical and spectroscopic data show that cover crops had a profound influence on the SOM and LF characteristics. Sumber: http://www.sciencedirect.com/science/article/pii/S0016706105000364 ….. Diunduh 17/3/2012

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