KESUBURAN TANAH & PEMUPUKAN Diabstraksikan Oleh : Smno.jurstnh.fpub.agst2012

1. KESUBURAN TANAH & PEMUPUKAN DiabstraksikanOleh: Smno.jurstnh.fpub.agst2012

2. Kesuburantanah Kesuburan Tanahadalahkemampuansuatutanahuntukmenghasilkanproduktanaman yang diinginkan, padalingkungantempattanahituberada. Produktanamanberupa: bunga, buah, biji, daun, umbi, getah, akar, trubus, batang, biomassa, naungan, penampilanestetika, danlainnya. Tanah memilikikesuburan yang berbeda-bedatergantungsejumlahfaktorpembentuktanah yang merajaidilokasitersebut, yaitu: Bahaninduk, Iklim, Relief, Organisme, danWaktu. Tanah merupakanfokusutamadalampembahasanilmukesuburantanah, sedangkan“tanaman” merupakanindikatorutamabagi “kesuburantanah”. Diunduh dari: http://id.wikipedia.org/wiki/Kesuburan_tanah..

3. 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..

4. Mengelolakesuburantanahdapatdilakukandenganmetode-metodevegetatifdanmekanikMengelolakesuburantanahdapatdilakukandenganmetode-metodevegetatifdanmekanik Upaya yang dapatdilakukanuntukmenjagakeseburantanahsebagaiberikut: a. Metodevegetatifdilakukandengancara-cara: Penanamantanamansecaraberjalurtegak lulus terhadaparahaliran(strip cropping). Penanamantanamansecaraberjalursejajargariskontur (contour strip cropping). Penutupanlahan yang memilikilerengcuramdengantanamankeras (buffering) Penanamantanamansecarapermanenuntukmelindungitanahdaritiupanangin (wind breaks). b. Metodemekanik yang umumdilakukanADALAH: Pengolahanlahansejajargariskontur (contour tilage).pengolahanlahandengancarainibertujuanuntukmembuatpolarongga-ronggatanahsejajarkontuldanmembentukigir-igirkecil yang dapatmemperlambatalilan air danmemperbesarinfiltrasiair Penterasanlahan miring (terracering).penterasanbertujuanuntukmengurangipanjanglerengdanmemperkecilkemiringanlerengsehinggadapatmemperlambatalilanair. Pembuatanpematang (guludan)dansaluran air sejajargariskontur.pembuatanpematanganbertujuanuntukmenahanalilanair. Pembuatancekdam.pembuatancekdambertujuanuntukmemperbendungalilan air yang melewatiparit-paritsehingga material tanahhasilerosi yang terangkutalirantertahandanterendapkanadannyacekdammenyebabkanerositanahdapatdikendalikan,lapisantanahmenebal,danproduktivitastanahmeningkat. Diunduh dari: http://lukmanituagam.blogspot.com/2011/03/menjaga-kesuburan-tanah.html..

5. LIMA FAKTOR PENGELOLAAN TANAH PengendalianGULMA. PERGILIRAN TANAMAN PENGENDALIAN HAMA & PENYAKIT PENYEDIAAN UNSUR HARA Penyediaan AIR YANG CUKUP, Sesuaidengankebutuhantanaman

6. 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.

7. 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

8. MENGATASI KEKURANGAN NITROGEN Dinamika 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

9. 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.

10. PENTINGNYA Ca & Mg Keseimbangan Ca dan Mg Penambahan dan kehilangan Sisa tanaman & Pupuk Kandang Pupuk Komersial Mineral Tanah Ca dan Mg tersedia dalam tanah KAPUR PANEN TANAMAN Hilang pencucian Hilang Erosi

11. MEMPERTAHANKAN KETERSEDIAAN FOSFAT. Siklus P 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

12. 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 pencucian Kehilangan Fiksasi

13. 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

14. Classical C Pools Nonhumic substances—carbohydrates, lipids, proteins Humic substances—humic acid, fulvic acid, humin BOT berpengaruh terhadap: -Plant nutrition -Soil and Plant health -Soil physical, chemical and biological properties

15. 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. 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.

16. 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. Bacteria vs. Fungi Fungi 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.

17. Bacteria vs. Fungi  Fungi often produce more cell wall than cytoplasmic material when starved for N, and thus can extend into new regions of the soil without requiring balanced growth conditions. The filamentous growth structure of a fungus permits it to access C in one location and nutrients in another.

18. KANDUNGAN BAHAN ORGANIK TANAH How organic matter in soil influences the soil-plant relationship? 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

19. 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 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

20. Degradation: 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 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

21. FAKTOR IKLIM PENGARUHI BOT: Temperature: OM decomposition rapid in warm climates OM Decomposition is slower for cool regions Result: 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 Result: Under comparable conditions Av total OM increases as the effective moisture increases

22. Sumber: pgsgrow.com/blog/tag/organic-gardening/

23. Structure of soil, indicating presence of bacteria, inorganic, and organic matter Sumber: www.cartage.org.lb/en/themes/sci...ones.htm

24. PUPUK - PEMUPUKAN • Fertilizer is one management option used almost universally • Must replace soil nutrients lost by harvest • Over-fertilization can result in dangerous pollution • Technology has increased fertilizer efficiency

25. PENGELOLAAN KESUBURAN TANAH Goals regarding fertility • Increase yield • Reduce costs/unit production • Improve product quality • Avoid environmental pollution • Improve environmental health & aesthetics

26. TUJUAN PENGELOLAAN KESUBURAN TANAH • Efficient land managers: spend <20% of production costs on fertilizers, expect >50% increase in yields • Fertilizers may not be profitable if: • 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

27. TUJUAN PENGELOLAAN KESUBURAN TANAH • 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

28. TUJUAN PENGELOLAAN KESUBURAN TANAH • 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

29. TUJUAN PENGELOLAAN KESUBURAN TANAH • Three common pollutants: • Nitrates • Percolate through to groundwater • Not safe to drink • Cause “Blue-baby” syndrome – inhibits oxygenation of blood • Becoming common near heavily fertilized fields, feedlots, dairies • Phosphates • Pollute surface waters by runoff • Promotes algae growth in rivers/ponds • Depletes available oxygen in the water for fish

30. TUJUAN PENGELOLAAN KESUBURAN TANAH • 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

31. PENGELOLAAN LAHAN • Large- & Medium-Scale Management • Large-Scale • 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

32. PENGELOLAAN LAHAN • Disadvantages • 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 • Advantages • Minimal technological training & instrumentation needed • Field operations can be performed w/ standard, readily available, cheaper equipment

33. PENGELOLAAN LAHAN • Medium-Scale • 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

34. PENGELOLAAN LAHAN • 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

35. PENGELOLAAN LAHAN • 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

36. PENGELOLAAN LAHAN • Potential to substantially decrease fertilizer/chemical application rates • Berpotensimenurunkanbiayasaranaproduksi • Does require expensive technology, equipment & extensive technical knowledge

37. PENGAMBILAN CONTOH TANAH Metodebakupenentuankesuburantanah Use w/ precision farming to minimize inputs Accuracy of sample is key!!!!

38. PENGAMBILAN CONTOH TANAH • Depth & Number of Samples • Sampling depth – 7-12” for typical soil analysis • Shallower depth for no-till/sod crops – acid-layer can form at very top of soil structure • For accurate N analysis – 24-36” depth • For composite sampling – fewer # samples decreases accuracy of analysis

39. PENGAMBILAN CONTOH TANAH • Sampling Frequency, Time, & Location • New land, land new to you – yearly for 1st few yrs until you understand the soil • Every 2-3 yrs, unless concern for environmental problems • Analysis – determines which nutrients can be made available in the soil & which will need to be supplied • Samples often pulled in fall to provide enough time for analysis/amendments

40. PENGAMBILAN CONTOH TANAH • Spring sampling is more accurate, but conditions may not be favorable, or not sufficient time • Sampling row crops problematic • Can hit a fertilizer zone • Hard to get enough representative samples

41. PENGAMBILAN CONTOH TANAH • Uniformity of Sampling Areas • Examine field for differences in soil characteristics, past treatments • PERHATIKANLAH: • Uniformity of productivity • Topografidan relief • Teksturtanah • Strukturtanah • Drainage • Kedalaman/warna topsoil • Pengelolaanhama-penyakittanaman

42. PENGAMBILAN CONTOH TANAH • Sampling area • Each composite sample should represent <12.5 ac • Grid sampling can be as small as you need • 5-10 ac grids are common • Providing Detailed Soil & Cropping Background • Helps to provide w/ soil analysis to increase accuracy of fertilizer recommendations

43. PENGAMBILAN CONTOH TANAH • Perhatikanjugahal-halberikut: • Previous crop • Crop (s)) to be grown • Realistic yield goal • Last liming & fertilization rates • Manure applications • Soil series (if known) • Drainage info • If irrigation used

44. UJI TANAH = Soil Tests Law of the Minimum: growth of the plant is limited most by the essential plant nutrient present in the least relative amount (first-limiting) • Soil Acidity Evaluation • pH measured w/ electrode & solution • Lime requirement – amount of lime required to achieve desired pH • Reported as buffer pH

45. UJI TANAH = Soil Tests Ujitanahuntuk N • No good tests for soil available N • Most states provide N recommendations based on yrs of field plots trials on various crops, soils, management, fertilizers • N recommendations consider: • Previous crops • Estimates N carryover • N needed to decompose residues • Projected yields • Climate

46. UJI TANAH = Soil Tests • Lab N tests accurate, but nearly impossible to interpret • Some will discourage N testing • Behavior of carryover N unpredictable – can make analyses invalid • Leaching • Denitrification • Mineralization • Climate

47. UJI TANAH = Soil Tests • N recommendations based on yield goals rather than soil reserves • Corn Rule – 1.2-1.4#N/bu of yield goal • How much N should be recommended for corn following corn, expected yield 120 bu/ac? • How much N should be recommended for corn following soybeans, expected yield 195 bu/ac?

48. UJI TANAH = Soil Tests • Soil Tests for P & K • Widely used to predict probability of crop response to fertilization • Survey: • 47% soil tested medium to low for P • 43% soil tested medium to low for K • P & K soil levels declining in many states • P testing • Quite reliable – soil P is very stable from yr to yr

49. UJI TANAH = Soil Tests • Most soil P unavailable to crops • Soil test extracts & measures what may actually be available • K testing • Tests both exchangeable & soluble reserves • Conflicting testing procedures over which is most accurate • Some estimate upper threshold needs ~159-246#/ac (above which no response to K fertilizer) • Others - 335#/ac on clay soils (calculated based on soil CEC – higher CEC = decreased available K) • Some experimentation w/ soil probes checking K, NO3, PO4, SO4

50. UJI TANAH = Soil Tests Uji Tanah untuk Ca danMg • Related to need for lime • Well-limed soils rarely Ca & Mg deficient • Mg deficiency more common than Ca • Coarse-textured or acidic soils • Many yrs using non-Mg containing lime • Ujitanahuntuk Mg : • Exchangeable soil Mg • % Mg saturation of soil colloids • Ratio of K:Mg