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PENGELOLAAN KESUBURAN TANAH RAMAH LINGKUNGAN Oleh : Prof.Dr.Ir.Soemarno,M.S . FP-UB, September 2013. KESUBURAN TANAH.
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PENGELOLAAN KESUBURAN TANAH RAMAH LINGKUNGAN Oleh: Prof.Dr.Ir.Soemarno,M.S. FP-UB, September 2013
KESUBURAN TANAH Kesuburan Tanah adalah kemampuan suatu tanah untuk menghasilkan produk tanaman yang diinginkan, pada lingkungan tempat tanah itu berada. Produk tanaman 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 mutu kesuburan tanah. Diunduh dari: http://id.wikipedia.org/wiki/Kesuburan_tanah....9/9/2012
CARA MENJAGA KESUBURAN TANAH Untukmenjagakesuburantanahbisadilakukandengancarasebagaiberikut : Gunakanjerami. Padatanahsawah, biasanyasetelahpanenpadikitaselalumembuangdanmembiarkanjeramiditumpukdipinggirsawah. Padahaljeramiitubisakitamanfaatkanuntukmenyuburkantanah. Sebarkanjeramitersebutkelahandanratakan. Kemudiantaburkanserbukdolomitkeatasjeramitersebut. Fungsidolomituntukmembantumempercepatpelapukandaunjeramidanbisamengaturtingkatkeasamantanahsehinggatanahbisalebihmatangdanlahanbisasegeraditanami.Setelahsekitarseminggulahantersebutbisalangsungdibajakdanjerami yang belumlapukbisadibenamkankedalamtanah. LubangresapanBiopori. Padatamanatauhalamanrumahbisakitalakukanmetodebiopori. Caranyalubangitanahsecarategaklurusdenganmenggunakanpipabesidengan diameter sekitar 10-20 cm dankedalamantanahsekitar 100 cm. Jarakantarlubangresapanbioporiadalah 50-100 cm. Kebutuhanjumlahlubangresapanbiopori yang diperlukanberdasarkanluastutupanbangunan. Bilatutupanbangunandenganluas 20 m2 diperlukanlubangresapanbioporisebanyak 3 unit dansetiaptambahanluastutupanbangunan 7 m2 diperluhantambahan 1 unit lubangresapanbiopori. Dalampemeliharaannyalubangresapanbioporiinidiisisampahorganiksecaraberkaladanmengambilsampahtersebutsetelahmenjadikomposdiperkirakan 2-3 bulansetelahterjadiprosespelapukan. TanamanCrotalaria.Untuklahankritisbisadimanfaatkanuntukditanamitanaman crotalaria. Akartanaman crotalaria bisamengikat nitrogen danunsur lain yang sangatdibutuhkantanahuntukmenjadisubur. Daundanbatangtanaman crotalaria sangatbaikdijadikanpupukhijau (kompos) karenamengandungunsur-unsur yang sangatdibutuhkantanahdantanamandibandingpupukhijaudaritanaman lain. Diunduh dari: http://rishadicorp.blogspot.com/2011/03/cara-menjaga-kesuburan-tanah.html..
MENJAGA KESUBURAN TANAH DENGAN CARA METODE VEGETATIF DAN MEKANIK • Upaya yang dapatdilakukanuntukmenjagakeseburantanahsebagaiberikut • Metodevegetatifdilakukandengancara-caraberikut • penanamantanamansecaraberjalurtegak lulus terhadaparahaliran(strip cropping). • penanamantanamansecaraberjalursejajargariskontur (contour strip cropping). • penutupanlahan yang memilikilerengcuramdengantanamankeras (buffering) • penanamantanamansecarapermanenuntukmelindungitanahdaritiupanangin (wind breaks). • b.metodemekanik yang umumdilakukansebagaiberikut. • pengolahanlahansejajargariskontur (contour tilage).pengolahanlahandengancarainibertujuanuntukmembuatpolarongga-ronggatanahsejajarkontuldanmembentukigir-igirkecil yang dapatmemperlambatalilan air danmemperbesarinfiltrasi air • penterasanlahan miring (terracering).penterasanbertujuanuntukmengurangipanjanglerengdanmemperkecilkemiringanlerengsehinggadapatmemperlambatalilan air. • pembuatanpematang (guludan)dansaluran air sejajargariskontur.pembuatanpematanganbertujuanuntukmenahanalilan air. • pembuatancekdam.pembuatancekdambertujuanuntukmemperbendungalilan air yang melewatiparit-paritsehingga material tanahhasilerosi yang terangkutalirantertahandanterendapkanadannyacekdammenyebabkanerositanahdapatdikendalikan,lapisantanahmenebal,danproduktivitastanahmeningkat Diunduh dari: http://lukmanituagam.blogspot.com/2011/03/menjaga-kesuburan-tanah.html..
PEMULIHAN KESUBURAN TANAH Chapter Four – Restoring Soil Fertility in Sub-Sahara Africa Mateete Bekunda, Nteranya Sanginga, Paul L. Woomer. Advances in Agronomy. Volume 108, 2010, Pages 183–236 Conceptual diagram of the soil fertility restoration process and the controlling factors. Diunduh dari: http://www.sciencedirect.com/science/article/pii/S0065211310080041.. 9/9/2012
ISFM: INTEGRATED SOIL FERTILITY MANAGEMENT ISFM : an approach to sustainable and cost-effective management of soil fertility. ISFM attempts to make the best use of inherent soil nutrient stocks, locally available soil amendments and mineral fertilizers to increase land productivity while maintaining or enhancing soil fertility. ISFM is a shift from traditional fertilizer response trials designed to come up with recommendations for simple production increases. The goal of ISFM is to develop comprehensive solutions that consider such diverse factors as weather, the presence of weeds, pests and diseases, inherent soil characteristics, history of land use and spatial differences in soil fertility. It involves a range of soil fertility enhancing methods, such as improved crop management practices, integration of livestock, measures to control erosion and leaching, and measures to improve soil organic matter maintenance. ISFM strategies include the combined use of soil amendments, organic materials, and mineral fertilizers to replenish soil nutrient pools and improve the efficiency of external inputs. Diunduh dari: http://www.aglearn.net/isfmMod1.html ...... 9/9/2012
ISFM: INTEGRATED SOIL FERTILITY MANAGEMENT Key aspects of the ISFM approach include: Replenishing soil nutrient pools Maximizing on-farm recycling of nutrients. Reducing nutrient losses to the environment. Improving the efficiency of external inputs ISFM’s basic focus is on sustainability. The framework of sustainability involves 3 essential components: Adequate, affordable food, feed and fiber supplies; A profitable system for the producer; and Responsible safeguards for the environment. Sumber: http://www.back-to-basics.net/efu/pdfs/mey.pdf Diunduh dari: http://www.aglearn.net/isfmMod1.html ...... 9/9/2012
ISFM: INTEGRATED SOIL FERTILITY MANAGEMENT • Goals of a Sustainable Soil Fertility Management Program • To sustain high crop productivity and crop quality in food and fiber production (not maximum yields, which typically require excessive nutrient inputs to achieve) • (a). Crop productivity, crop quality, and the economic viability of a given farming operation • 2. To minimize environmental quality and human health risks associated with agricultural production • Important steps in minimizing human health risks and on- and off-farm impacts • i. Avoid the use of all synthetically compounded materials (e.g., fertilizers and pest control agents, etc.) known to have an associated environmental quality or human health risk • ii. Avoid creating non-point source pollution through surface runoff and leaching. Agricultural nutrients can degrade the quality of groundwater or the water in rivers, lakes, wetlands, and estuaries through eutrophication. • iii. Prevent soil erosion and sedimentation of waterways. Soil loss reduces production capacity and soil entering waterways may degrade aquatic habitat. • iv. Close nutrient cycles as much as possible within the field and farm to reduce energy used and environmental impact of food and fiber production • v. Close nutrient cycles at multiple scales (e.g., watershed, regional, and national scales) Diunduh dari: http://184.108.40.206/wp-content/uploads/2010/05/unit_1.1_fertility.pdf...... 9/9/2012
ISFM: INTEGRATED SOIL FERTILITY MANAGEMENT Soil fertility: The capacity of a soil to provide nutrients required by plants for growth. This capacity to provide nutrients to crop plants is in part influenced by the physical properties of soils and is one component of soil fertility. Desirable soil physical properties and the capacity of the soil to provide nutrients for growing crops are both soil quality indicators. Soil quality indicators Soil accepts, holds, releases, and mineralizes nutrients and other chemical constituents Soil accepts, holds, and releases water to plants, streams, and groundwater Soil promotes good root growth and maintains good biotic habitat for soil organisms Soil resists degradation (e.g., erosion, compaction) Soil maintains good soil structure to provide adequate aeration Good soil structure allows for rapid water infiltration Soil has a moderate pH (~6.0–7.0) at which most essential soil nutrients are available Soil has low salinity levels Soil has low levels of potentially toxic elements (e.g., boron, manganese, and aluminum) Balanced fertility that provides adequate levels of macro- and micronutrients that plants and soil microbes require Diunduh dari: http://220.127.116.11/wp-content/uploads/2010/05/unit_1.1_fertility.pdf...... 9/9/2012
ISFM: INTEGRATED SOIL FERTILITY MANAGEMENT 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: SOM has a large capacity to hold and release inorganic (cropavailable) nitrogen and other essential nutrients. Organic matter inputs enhance the stability of soil aggregates, increase the porosity and permeability to water and air, and improve the water-holding capacity of soils. Building or maintaining the level of soil carbon provides the energy and nutrients necessary to stimulate the soil biological activity responsible for decomposition, the formation of soil aggregates, and more desirable soil structure. Properly timed tillage: Stimulates the decomposition of SOM by increasing aeration (O2 supply to aerobic microbes), breaking up compacted areas and large soil clods, and exposing a greater surface area of SOM for microbial breakdown. Appropriate tillage also increases water infiltration and good drainage. Irrigation: For irrigation-dependent crops, manage soil moisture between 50% and 100% of field capacity through soil moisture monitoring and moisture retention techniques such as mulching Use of 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. Diunduh dari: http://18.104.22.168/wp-content/uploads/2010/05/unit_1.1_fertility.pdf...... 9/9/2012
ISFM: INTEGRATED SOIL FERTILITY MANAGEMENT Memperbaikidanmemeliharasifatkimiatanah (a) Benchmarks of optimal soil chemistry Balanced levels of available plant nutrients (see Unit1.11, Reading and Interpreting Soil Test Reports, for more on this subject) Soil pH ~6.0–7.0: At this soil pH the greatest amount of soil nutrients are available to crops Salinitasrendah: Akumulasigaramdalamtanahdapatmenimbulkangangguanpadatanamanakibatcekaman (stress) air dangaram. Diunduh dari: http://22.214.171.124/wp-content/uploads/2010/05/unit_1.1_fertility.pdf...... 9/9/2012
ISFM: INTEGRATED SOIL FERTILITY MANAGEMENT Sustainable agricultural practices used to develop and maintain optimal soil chemical properties Provide a balanced nutrient supply for the crop. As plant growth is related to the availability of the most limiting nutrient, it is essential that we consider the balance (ratios) of soil nutrients available. Yield and quality may be limited if levels of some nutrients are too high while others are too low. Conduct soil analysis with periodic monitoring. Soil analysis provides current quantitative information on the nutrient profile of a given soil. Soil analysis report data should be compared to established optimal benchmarks of soil fertility when developing soil amendment plans to assure adequate but not excessive nutrient applications. Comparing results from multiple years of sampling will show whether you are depleting or accumulating soil nutrients over time, and indicate whether changes in fertility management are needed. Conduct plant tissue testing. In-season plant tissue testing provides current quantitative data on the nutrient profile of growing plants. Such data may be compared with recommended nutrient levels and may be used to determine the need for mid-season supplemental fertilizing. However, be aware that most tissue testing information has been developed for systems using synthetic chemical fertilizers, and sufficiency levels may well differ for organic systems. Diunduh dari: http://126.96.36.199/wp-content/uploads/2010/05/unit_1.1_fertility.pdf...... 9/9/2012
SOIL FERTILITY MANAGEMENT Hubungan Tanaman – Tanah dan Lingkungannya Faktor-faktor yang mempengaruhi kesuburan tanah menjadi fokus pengelolaan kesuburan tanah untuk mendapatkan hasil yang optimal Diunduh dari: http://www.organicagriculture.co/soil-fertility-management.php...... 10/9/2012
SOIL FERTILITY MANAGEMENT Soil quality is of fundamental importance for agricultural production, and soil fertility management is increasingly becoming a central issue in the decisions on food security, poverty reduction and environment management. For the purpose of safe ecological stewardship and achieving global food security, emphasising soil fertility management is becoming more and more important. The crucial role of soil fertility management for sustainable resource management and food security has been recognised only quite recently. Major plant nutrient input and output from agricultural systems Diunduh dari: https://athene.umb.no/emner/pub/EDS215/LectureSoil.htm ...... 10/9/2012
SOIL FERTILITY MANAGEMENT Plant nutrient management for improving crop productivity in Nepal Sherchan and K.B. KarkiSoil Science Division, Nepal Agricultural Research Council (NARC)Kathmandu, Nepal An integrated nutrient model developed quite some time ago as shown below figure was a successful programme but it has not been popularized or has not been well adopted by large number of farmers. There should be a follow up study to see the impact on soil fertility management and to look on how best we can promote to wider areas. Integrated plant nutrient components in the Nepalese farming system Diunduh dari: http://www.fao.org/docrep/010/ag120e/AG120E10.htm ...... 10/9/2012
LIMA FAKTOR PENGELOLAAN TANAH Pengendalian GULMA . PERGILIRAN TANAMAN (ROTASI TANAMAN) PENGENDALIAN HAMA & PENYAKIT (INTEGRATED PEST MANAGEMENT) PENYEDIAAN UNSUR HARA INTEGRATED PLANT NUTRIENT MANAGEMENT Penyediaan AIR YANG CUKUP Soil moisture management and conservations
DINAMIKA HARA TANAH Mempertahankan jumlah optimum unsur hara hanya dapat terlaksana dengan menciptakan keseimbangan yang baik antara penambahan dan kehilangannya Benefits of Organic Matter Increases soil CEC Stabilizes nutrients Builds soil friability and tilth Reduces soil splash Benefits of Organic Matter Reduces compaction and bulk density Provides a food source for microorganisms Increases activities of earthworms and other soil critters 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.
POKOK-POKOK PENGELOLAAN KESUBURAN TANAH. 1. Suplai nitrogen dari: Sisa Tanaman Tanaman biasa Pupuk kandang Tanaman legume Hujan & irigasi Pupuk hijau 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
MENGATASI KEKURANGAN NITROGEN 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 Pencucian Hilang Erosi
MEMPERTAHANKAN BAHAN ORGANIK TANAH Carbon Inputs to Soil Crop residues Cover crops Compost , and Manures Carbon Substrate The 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.
PENTINGNYA Ca & Mg Fungsi fisiologis Ca dan Mg dalam tanaman Penambahan dan kehilangan Sisa tanaman & Pupuk Kandang Pupuk Komersial Mineral Tanah Ca dan Mg tersedia dalam tanah KAPUR PANEN TANAMAN Hilang pencucian Hilang Erosi
MEMPERTAHANKAN KETERSEDIAAN FOSFAT. Fungsi P sangat penting dalam fisiologi tanaman Kehilangan & Penambahan P-tersedia Sisa tanaman Pukuk kandang Pukuk komersial Mineral P-tanah Bahan Organik Tanah P-tersedia dalam tanah Terangkut tanaman Hilang Pencucian Hilang Erosi Fiksasi
KETERSEDIAAN KALIUM Tanah mineral umumnya mengandung cukup banyak kalium, kisaran 40 ton setiap hektar lapisan olah tanah. Namun demikian hanya sebagian kecil yangtersedia bagi tanaman Kehilangan & Penambahan Kalium: Sisa tanaman & Pupuk Kandang Pupuk komersial Mineral-K lambat tersedia K-tersedia tanah Terangkut tanaman Kehilangan erosi Kehilangan Fiksasi Kehilangan pencucian
The Soil Food Web In 1 teaspoon of soil there are… 5 or more ------------ Earthworms Up to 100 ……………. Arthropods 10 to 20 bacterial feeders and a few fungal feeders ……. Nematodes Several thousand flagellates & amoeba One to several hundred ciliates ……. Protozoa 6-9 ft fungal strands put end to end ………. Fungi 100 million to 1 billion …………. Bacteria What is the Soil Foodweb and why is it so Important? The soil foodweb is the tonnes of beneficial bacteria, fungi, protozoa and nematodes that live in soil or compost whose value has been overlooked, undervalued and misunderstood for decades. Recent discoveries in soil biology show a huge potential to improve current organic, biological and conventional growing and farming and move away from costly synthetic inputs. Diunduh dari: http://soilfoodweb.ca/about_us.html...... 10/9/2012
CADANGAN KARBON TANAH Nonhumic substances—carbohydrates, lipids, proteins Humic substances—humic acid, fulvic acid, humin • BOT berpengaruhterhadap: • - Hara tanaman • - Kesehatantanahdantanaman • sifat-sifatfisika, kimiawidanbiologistanah
BOT ----- FRAKSI RINGAN The light fraction (LF) with a density of ~1.6 gm cm-3 is relatively mineral free and consists of partially decomposed plant material, fine roots and microbial biomass with a rapid turnover time. The LF is a source of readily mineralizable C and N, accounts for ~50% of total soil C and declines rapidly under cultivation. Carbon Sequestration and Soil Aggregation in Center-Pivot Irrigated and Dryland Cultivated Farming Systems Jeroen Gillabel, Karolien Denefb, John Brennerc, Roel Merckxd and Keith Paustian SSSAJ. Vol. 71 No. 3, p. 1020-1028 Diunduh dari: https://www.crops.org/publications/sssaj/articles/71/3/1020...... 10/9/2012
BOT --- FRAKSI BERAT --- The Heavy Fraction The heavy fraction (HF) is organic matter adsorbed onto mineral surfaces and sequestered within organomineral aggregates. The HF is less sensitive to disturbance an chemically more resistant than the LF. Long-term fertilization and manuring effects on physically-separated soil organic matter pools under a wheat–wheat–maize cropping system in an arid region of China Long Hai, Xiao Gang Li, Feng Min Li, Dong Rang Suo, Georg Guggenberger Soil Biology and Biochemistry. Volume 42, Issue 2, February 2010, Pages 253–259. About two thirds of macro OM was actually located within 2–0.05 mm organo-mineral associations or/and aggregates. Diunduh dari: . http://www.sciencedirect.com/science/article/pii/S0038071709004003..... 10/9/2012
Bacteria vs. Fungi Bacteria are smaller than fungi and can occupy smaller pores and thus potentially have greater access to material contained within these pores. Bacteria are less disrupted than are fungi by tillage practices commonly used in agriculture. Priming effects: Interactions between living and dead organic matter Yakov Kuzyakov Soil Biology and Biochemistry, Volume 42, Issue 9, September 2010, Pages 1363–1371 PEs (Priming effects) – the interactions between living and dead organic matter – should be incorporated in models of C and N dynamics, and that microbial biomass should regarded not only as a C pool but also as an active driver of C and N turnover. Sequence of processes inducing apparent (aPE) and real (rPE) priming effects: 1. Input of available organics by rhizodeposition (Exudation). 2. Activation of microorganisms (mainly r-strategists) by available organics (Activation). 3. Activation of K-strategists. 4. Production of extracellular enzymes that degrade SOM by K-strategists (Enzyme production). 5. SOM decomposition and production of available organics and mineral nutrients. 6. Uptake of nutrients by roots. The dynamics and sequence of individual processes are described in detail in Blagodatskaya and Kuzyakov (2008). → fluxes; — — → effects; ········ dynamics of apparent priming effects (aPEs) and real priming effects (rPEs). Diunduh dari: http://www.sciencedirect.com/science/article/pii/S0038071710001355 ...... 10/9/2012
Soil FungiFungi tend to be selected for by plant residues with high C/N ratios. Fungi have a greater influence on decomposition in no-till systems in which surface residues select for organisms that can withstand low water potentials and obtain nutrients from the underlying soil profile. Fungi mediate long term sequestration of carbon and nitrogen in soil through their priming effect S. Fontaine, C. Henault, A. Aamor, N. Bdioui, J.M.G. Bloor, V. Maire, B. Mary, S. Revaillot, P.A. Maron. Soil Biology and Biochemistry. Volume 43, Issue 1, January 2011, Pages 86–96 Fungi are the predominant actors of cellulose decomposition and induced PE and they adjust their degradation activity to nutrient availability. The predominant role of fungi can be explained by their ability to grow as mycelium which allows them to explore soil space and mine large reserve of SOM. The bank mechanism adjusting the sequestration of nutrients and carbon in soil organic matter (SOM) to the availability of nutrients in soil solution tested in this study. This mechanism is based on the assumption that microbial degradation of recalcitrant SOM (priming effect) is modulated by the concentration of nutrients in soil solution . When nutrient availability is low (a), for example because the plant uptake of nutrient is high, the microbial mining of SOM could be intense and eventually exceed the formation of new SOM through humification of fresh-C, leading to net destruction of SOM and release of mineral nutrients. In contrast, when soluble nutrients are abundant (b), microbial immobilization of N should increase while mining of SOM should decrease, leading to a greater sequestration of nutrients in SOM. Given that plant demand of mineral nutrients is highly variable and depends on many factors such as plant phenology, soil moisture and light availability, the bank mechanism could help to synchronize the availability of soluble nutrients to plant uptake. Numbers indicate the chronology of events induced by a change in plant uptake of nutrients. Diunduh dari: http://www.sciencedirect.com/science/article/pii/S0038071710003500...... 10/9/2012
PENTINGNYA BAHAN ORGANIK TANAH Bagaimana BOT mempengaruhihubungan Tanah-Tanaman? Decomposed organic matter provides nutrients for plant growth (Mineralization) It determines the soil’s temperature, air ventilation, structure and water management It contains bioregulators which affects plant growth It contains bioregulators, which affects plant growth (enzymes, hormones, etc.) Its carbon and energy content is the soil’s energy battery for future use It determines the soil’s capacity to compensating, regenerating and protecting the environment regenerating and protecting the environment. Organic matter decomposition and the soil food web When plant residues are returned to the soil, various organic compounds undergo decomposition. Decomposition is a biological process that includes the physical breakdown and biochemical transformation of complex organic molecules of dead material into simpler organic and inorganic molecules (Juma, N.G. 1998. The pedosphere and its dynamics: a systems approach to soil science. Volume 1. Edmonton, Canada, Quality Color Press Inc. 315 pp.) The continual addition of decaying plant residues to the soil surface contributes to the biological activity and the carbon cycling process in the soil. Breakdown of soil organic matter and root growth and decay also contribute to these processes. Carbon cycling is the continuous transformation of organic and inorganic carbon compounds by plants and micro- and macro-organisms between the soil, plants and the atmosphere. Diunduh dari: http://www.fao.org/docrep/009/a0100e/a0100e05.htm...... 10/9/2012
PENTINGNYA BOT Organic material in the soil is essentially derived from residual plant and animal material, synthesised by microbes and decomposed under influence of temperature, moisture and ambient soil conditions Soil organic matter is extremely important in all soil processes Cultivation can have a significant effect on the organic matter content of the soil In essentially warm and dry areas like Southern Europe, depletion of organic matter can be rapid because the processes of decomposition are accelerated at high temperatures Generally, plant roots are not sufficiently numerous to replace the organic matter that is lost Humic substances retain nutrients available on demand for plants Functions of humus: improved fertilizer efficiency; longlife N - for example, urea performs 60-80 days longer; improved nutrient uptake, particularly of P and Ca; stimulation of beneficial soil life; provides magnified nutrition for reduced disease, insect and frost impact; salinity management - humates “buffer” plants from excess sodium; organic humates are a catalyst for increasing soil C levels. Humus consists of different humic substances: Fulvic acids: the fraction of humus that is soluble in water under all pH conditions. Their colour is commonly light yellow to yellow-brown. Humic acids: the fraction of humus that is soluble in water, except for conditions more acid than pH 2. Common colours are dark brown to black. Humin: the fraction of humus that is not soluble in water at any pH and that cannot be extracted with a strong base, such as sodium hydroxide (NaOH). Commonly black in colour. The term acid is used to describe humic materials because humus behaves like weak acids. Fulvic and humic acids are complex mixtures of large molecules. Humic acids are larger than fulvic acids. Research suggests that the different substances are differentiated from each other on the basis of their water solubility. Fulvic acids are produced in the earlier stages of humus formation. The relative amounts of humic and fulvic acids in soils vary with soil type and management practices. The humus of forest soils is characterized by a high content of fulvic acids, while the humus of agricultural and grassland areas contains more humic acids. Diunduh dari: http://www.fao.org/docrep/009/a0100e/a0100e05.htm#TopOfPage...... 10/9/2012
MANFAAT BOT ➢ Storehouse for nutrients ➢ Source of fertility ➢ Contributes to soil aeration thereby reducing soil compaction ➢ Important ‘building block’ for the soil structure ➢ Aids formation of stable aggregates ➢ Improves infiltration/permability ➢ Increase in storage capacity for water. ➢ Buffer against rapid changes in soil reaction (pH) ➢ Acts as an energy source for soil micro-organisms Organic matter within the soil serves several functions. From a practical agricultural standpoint, it is important for two main reasons: (i) as a “revolving nutrient fund”; and (ii) as an agent to improve soil structure, maintain tilth and minimize erosion. As a revolving nutrient fund, organic matter serves two main functions: As soil organic matter is derived mainly from plant residues, it contains all of the essential plant nutrients. Therefore, accumulated organic matter is a storehouse of plant nutrients. The stable organic fraction (humus) adsorbs and holds nutrients in a plant-available form. Diunduh dari: http://www.fao.org/docrep/009/a0100e/a0100e04.htm#TopOfPage...... 10/9/2012
Degradasi: HILANGNYA BOT During field operations, fresh topsoil becomes exposed and dries rapidly on the surface Organic compounds are released to the atmosphere result from breakdown of soil aggregates bound together by humic materials Unless the organic matter is quickly replenished, the system is in a state of degradation leading eventually to un-sustainability The removal of crop residues in dry ecosystems, which are inherently marginal, can cause such systems to be quickly transformed from a stage of fragility to total exhaustion and depletion Selecting Indicators to Evaluate Soil Quality Zueng-Sang ChenDepartment of Agricultural ChemistryNational Taiwan University, Taipei, 10617, Taiwan ROC, 1999-08-01 Changes in Soil Organic Matter Content (MT/Ha) Calculated in Taiwan under Different Soil Management Systems with Long-Term Application of Composts or Fertilizers Diunduh dari: http://www.agnet.org/library.php?func=view&style=&type_id=4&id=20110808172707&print=1...... 11/9/2012
FAKTOR YG PENGARUHI BOT Natural factors: ➢ Climate ➢ Soil parent material: acid or alkaline (or even saline) ➢ Land cover and or vegetation type ➢ Topography – slope and aspect Human-induced factors: ➢Land use and farming systems ➢Land management (cultivation) ➢Land degradation Potential environmental effects of corn (Zea mays L.) stover removal with emphasis on soil organic matter and erosion Linda Mann, Virginia Tolbert, Janet Cushman. Agriculture, Ecosystems & Environment. Volume 89, Issue 3, May 2002, Pages 149–166. Simplified conceptual model of interactions and feedbacks between tillage and soil factors affecting soil organic matter content (adapted from Fig. 2 in Paustian et al. (1997)). Diunduh dari: http://www.sciencedirect.com/science/article/pii/S0167880901001669 ...... 10/9/2012
FAKTOR IKLIM PENGARUHI BOT: Temperature: OM decomposition rapid in warm climates OM Decomposition is slower for cool regions Within zones of uniform moisture and comparable vegetation -- Av total OM increases 2x to 3x for each 10 deg C fall in mean temperature Moisture: OM decomposition rapid in warm climates OM Decomposition is slower for cool regions Under comparable conditions , Av total OM increases as the effective moisture increases. Diunduh dari: ...... 10/9/2012
Sumber: pgsgrow.com/blog/tag/organic-gardening/ SOIL is Alive! This living-life helps with garden health, fertility, decomposition of organic matter, replenishment of nutrients, humus formation, and promotion of root growth, nutrient uptake, and herbicide and pesticide breakdown. Diunduh dari: http://www.organicgardeninfo.com/soil.html ...... 11/9/2012 The organic matter in SOIL helps feed all the organisms and release nutrients. Humus acts like glue that holds all the particles together, and it helps prevent erosion and increases a garden's moisture holding ability. Humus also increases fertility by making nutrients more available to the organic garden plants' roots.
Structure of soil, indicating presence of bacteria, inorganic, and organic matter Sumber: www.cartage.org.lb/en/themes/sci...ones.htm The high productivity of most virgin soils has always been associated with their high content of organic matter, and the decrease in the supply with cultivation has generally been paralleled by a corresponding decrease in productivity.
PUPUK - PEMUPUKAN • Fertilizer is one management option used almost universally • Must replace soil nutrients lost by harvest • Over-fertilization can result in dangerous pollution • Teknologi meningkatkan efisiensi pupuk
PENGELOLAAN KESUBURAN TANAH SASARANNYA: • Peningkatan hasil produksi • Reduce costs/unit production • Improve product quality • Avoid environmental pollution • Memperbaiki kesehatan dan estetika lingkungan
TUJUAN PENGELOLAAN KESUBURAN TANAH • Efficient land managers: spend <20% of production costs on fertilizers, expect >50% increase in yields • Pupuk tidak menguntungkan kalau : • Water is the most limiting factor • Other growth hindrances – insects, diseases, acidity, extreme cold • Increased yield has less market value than the cost of buying/app of fertilizer
TUJUAN PENGELOLAAN KESUBURAN TANAH PUPUK – INPUT EKONOMI • Fertilizers – generally most profitable farm input • Soil fertility problems usually the easiest to solve • Soil nutrients typically present in finite amounts, don’t replenish themselves • Crops typically contain: (in rank of amount found in the plant) N, K, Ca, P, Mg, S
TUJUAN PENGELOLAAN KESUBURAN TANAH EKOLOGI-EKONOMI PUPUK • Utilizing fertilizers may help cut unit cost of production by maximizing yield • Improved fertility = improved yields, improved aesthetic appeal • Environmental concerns abound • Fertilizer laws viewed as lax by some • Farmers may be the primary cause of non-point-source pollution
TUJUAN PENGELOLAAN KESUBURAN TANAH • Bahan polutan : • Nitrat • Percolate through to groundwater • Not safe to drink • Cause “Blue-baby” syndrome – inhibits oxygenation of blood • Becoming common near heavily fertilized fields, feedlots, dairies • Fosfat • Pollute surface waters by runoff • Promotes algae growth in rivers/ponds • Depletes available oxygen in the water for fish
TUJUAN PENGELOLAAN KESUBURAN TANAH EKOLOGI PEMUPUKAN • Wise use of fertilizers must be encouraged, actually improve the environment • Crops, trees, etc. - remove more CO2, decrease sediment, dust, erosion • Plays important role for future of the planet Diunduh dari: ...... 10/9/2012
PENGELOLAAN LAHAN • Pengelolaan Lahan sekala Besar –Medium • Pengelolaan Sekala Besar • Low levels of operational precision, little reliance on sophisticated technology • May be most feasible/profitable for some • Simple & low-tech • Some shy away from high tech for other reasons
PENGELOLAAN LAHAN • Kerugian • Some parts of field may receive too much/little fertilizer or pesticide • Less than optimal yields • Inefficient use of fertilizers & pesticides • Higher cost of production/unit • Environmental pollution due to over application • Keuntungan • Minimal technological training & instrumentation needed • Field operations can be performed w/ standard, readily available, cheaper equipment.
PENGELOLAAN LAHAN • Pengelolaan sekala medium • Subdivide field into two+ management units • Delineation may be based on: • Soil types • Past management differences • Farmer’s observations • Ex. High, medium, low N application areas in the field • Same equipment/technology needs as for large-scale management farmers
PENGELOLAAN LAHAN • Pengelolaan sekala Medium : • Does improve efficiency of farm inputs • Can reduce excessive applications of chemicals/fertilizers • May do spot treatments/applications w/in a field due to field observations • Small-Scale Management (Precision Farming) • Global Positioning System (GPS) – network of U.S. satellites w/ a signal detection system used to locate positions on the ground Diunduh dari: ..
PENGELOLAAN LAHAN Precision Farming • Soil sample fields on a grid • Data collection points no more than a few feet apart • Each sample site mapped using GPS • Custom applicators can custom apply fertilizers at variable rates that change constantly as the applicator travels the field – variable rate application, site-specific management, precision farming Diunduh dari: ...... 10/9/2012
PENGELOLAAN LAHAN Precision Farming • Potential to substantially decrease fertilizer/chemical application rates • Potential to substantially decrease input costs • Does require expensive technology, equipment & extensive technical knowledge Diunduh dari: ...... 10/9/2012