PRINSIP-PRINSIP MANAJEMEN KESUBURAN TANAH. Bahan Kajian MK. Manajemen Kesuburan Tanah

1. PRINSIP-PRINSIP MANAJEMEN KESUBURAN TANAH. Bahan Kajian MK. Manajemen Kesuburan Tanah Diarikan soemarno - jursntnhfpub - Sept 2013

2. PRINSIP-PRINSIP MANAJEMEN KESUBURAN TANAH Tujuan Program MST. Concepts of large scale, intermediate and small scale “precision” farming. Soil and plant sampling, testing, and interpretation. Kesuburan tanah dan Manajemen pupuk Aplikasi, efisiensi dan manfaat pupuk.

3. SASARAN MANAJEMEN KESUBURAN TANAH • Meningkatkan hasil tanaman (pangan dunia) • Mereduksi biaya per satuan hasil • Kualitas produk (not always a factor - fast growing wood is lower quality than slow-growing wood) • Mereduksi gangguan penyakit (can go the other way by making tissues protein-rich and juicy for bugs) • Mencegah pencemaran lingkungan (new since the 60's - never used to be considered) • Memperbaiki kesehatan dan estetika lingkungan • Memperbaiki habitat liar (hunting permits)

4. TUJUAN PRODUSEN Cut the unit cost of production by producing the largest possible crop. Match the crop needs with available nutrient supply. Nitrates, phosphates, and pesticides – the old way Typical crop uptake values (archaic units - lb/acre - multiply by 1.12 to get kg/ha; also note that P as P2O5 and K as K2O)

5. Aplikasi pupuk yang bijaksana dapat melindungi lingkungan. Pupuk memperbaiki pertumbuhan tanaman Semakin banyak tanaman, semakin banyak CO2 yang diserap (diambil) dari udara atmosfir Semakin banyak vegetasi penutup muka lahan , semakin sedikit erosi dan pencemaran perairan

6. SEKALA PENGELOLAAN LAHAN Large-scale: Treating the entire field as one management unit. SEDERHANA DAN TEKNOLOGI TEPATGUNA Presisioperaisonalrelatifrendah. Tidakmemperhitungkanvariabilitaslahandankandunganharanya. Memerlukansedikitinstrumentasidanlatihanteknologi Produksitidakmeratadanpotensipencemartanlingkungan

7. SEKALA MEDIUM. Medium-scale: Sub-dividing the field into two or more management units requiring different applications of fertilizer, pesticides, and irrigation. Biasanyadipraktekkanatasdasarintuitif Memungkinkanpenerapanstandarlapangan Based on soil types, drainage characteristics, empirical observation, and ease of boundary delineation Efisiensilebihbaikdanpencemaranlingkunganlebihsedikit

8. SEKALA KECIL. Small-scale (precision): A system in which infinitesimal land management units occur within a single field. Menggunakan GPS danmengembangkan basis-data elektronikuntuktanahdantanaman Memerlukanpenerapanberagamteknologidanperalatannya Lebihpraktisuntukkomodititanaman yang nilaiekonominyatinggi

9. .SAMPLING TANAH. • No amount of care in preparation and analysis can overcome poor or inappropriate soil sampling • Soils vary continuously with space and depth; you cannot sample all the variability • Know your horizons and sample accordingly when possible • We often dig a quantitative pit and get horizon depths and then sample with augers thereafter • Often sampling plow layer in ag soils; this will NOT work in wildland soils.

10. KEDALAMAN DAN BANYAKNYA CONTOH Over-riding guide: Take a sample so that it represents what it is intended to represent Kedalamanlapisanbajak (traditional ag) At 30 cm (~1 ft) increments; alternate 30 cm increments Horisontanahuntuksistem yang masihutuh Tipetanah Sampelkompositterdiriatas 5-20 sub-sample untuksetiapsampelanalisis Hara setiaptahun, status garamsetiaptahun.

11. Horizontal variation: sample by landscape strata that make sense (land use, soil series, slope, aspect, current vegetation, etc.)

12. Variasi vertikal: Perlu diketahui kedalaman horison, dan sampling tanah pada kedalaman horison ini

13. Variasi hasil analisis tanah akibat perbedaan kedalaman sampling tanah. Batas-batas horison tanah jelas Lokasi mana yang memberikan %N tanah yang paling tepat? Lokasi 1 paling representatif, Sampel tanah menurut horison

14. Variasi hasil analisis tanah akibat perbedaan kedalaman sampling tanah. Batas-batas horison difuse (baur) Lokasi mana yang memberikan %N tanah yang paling tepat? Ketiga lokasi bagus. Di lokasi 3 sampling lebih dari satu kedalaman

15. Kesalahan karena variasi ketebalan horison tanah Kalau hal ini terjadi, maka harus dilakukan observasi lebih akurat dan detail. Tentukan kedalaman “median” dan ambil banyak contoh tanah. Pada setiap titik sampel diukur kedalaman horison , dan kalau memungkinkan dirata-rata.

16. UJI TANAH pH, acidity / alkalinity: Electrode in 1:1 or 1:2 soil:water ratio with 0.01M CaCl2. Some people use distilled water – this generally gives a higher pH – why? Al, H+ displacement. Also: review lime requirement. Garam-garam larut: Saturated paste extract 1:1 or 1:2 Nitrogen: Not reliably precise. Total N, C:N ratio, extractable ammonium and nitrate, N mineralization, resins….None cheap or very quantitative.

17. .UJI P-TANAH • Phosphorus: • The book says this: • Bray 1: 0.025 M HCl = 0.03 M NH4F (for acidic soils) • Mehlich 1: 0.05 M HCl + 0.025 M H2SO4 (for acidic soils) • Olsen’s bicarbonate: 0.5 M NaHCO3 at pH 8.5 (for neutral and alkaline soils; assumes all goes to H2CO3 in acidic soils) • Mehlich 3: 0.2 M acetic acid + 0.25 M ammonium nitrate + 0.015 M NH4F + 0.013 M HNO3 + + 0.001 M EDTA

18. Uji K, Ca, Mg dan S Potassium, Calcium and Magnesium: Exchange with ammonium chloride, potassium chloride or acetate (CEC). No one I know uses the bicarbonate + DPTA extract mentioned. Total digests are usually not useful except for research purposes. Sulfur: SO42- is the preferred way, by water, phosphate, LiCl. Total S not usually useful except for research, but with new CHNS analyzers, it is now easy to get.

19. Uji Unsur Hara Mikro Boron: Hot water extract. Some people use cold water and works just as well. Zn, Fe, Mn, Cu: Many trials on this using 0.1 M HCl, Coca-Cola (carbonic acid + sugar), chelates like DPTA Mo, Ni: Totals, resins, chelates Soil tests are changing – resins are coming into play now and must be checked against older methods. Also, total analysis may become easier now, as for example CHNS analysis.

20. Uji tanah vs. Analisis Tanaman • Leibigs Law of the Minimum: • Growth is limited by the essential nutrient present in the lowest relative amount. • Thus, the plant is the ultimate judge. However - • In annual crops, plant analysis may be too late (already grown) • In forests and range, plant analysis is not too late (growth goes on for years) • Plant analysis is generally more sensitive than soil analysis.

21. ANALISIS TANAMAN • Not generally favored by ag people because it is "too late“ and doubles the analytical expense • Sangat disenangi oleh pakar kehutanan karena dianggap lebih sensitif - tanaman merupakan “arbiter” akhir • Analisis total tanaman : digunakan untuk riset-riset pertanian dan kehutanan • Analisis daun, sering digunakan dalam pendugaan status hara / nutrisi tanaman • Analisis kering oven (65oC) • Analisis Total - nilai-nilai ambang atau nilai kritis.

22. .BATAS AMBANG HARA DALAM TGANAMAN

23. . • Analisis vektor untuk menduga respon pertumbuhan (Bobot + Konsentrasi) • DRIS (diagnosis recommendation integrated system) • Kisaran kritis hara tanaman • Gejala defisiensi visual • Mobile nutrients like N, S, P, Mg, K symptoms appear on older tissues because of translocation • Unsur hara Imobil seperti Cu, Mn, Ca, Fe ; gejala defisinesinya muncul pada jaringan muda.

24. UNSUR HARA TANAMAN

25. Unsur Hara Tanaman • Bagaimana tanaman memperoleh dan menggunakan hara? 1. Mengapa unsur hara itu penting? • 2. Apa saja unsur hara esensial itu? • Sistem klasifikasi hara • 3. Unsur hara dalam tanah • Ketersediaan hara • Penjerapan oleh partikel tanah • Efek pH tanah • 4. Akar dan penyerapan hara • Struktur Akar • Zone penyerapan • 4. Mycorrhizae • 5. Nitrogen – unsur hara yang biasanya membatasi tanaman

26. Mengapa unsur hara itu penting? • In most natural soils, the availability of mineral nutrients limits plant growth and primary productivity. • Nutrient limitation is an important selective pressure and plants exhibit many special traits related to the need to acquire and use mineral nutrients efficiently.

27. Apa saja unsur hara esensial? Hara Makro - present in relatively high concentrations in plant tissues. N, K, P, Ca, Mg,S, Si Nitrogen is most commonly limiting to productivity of natural and managed soils. Phosphorus is next most limiting, and is most limiting in some tropical soils. Hara mikro - present in very low concentrations in plant tissues.

28. Apadefinisiunsurhara “essensial”? In its absence the plant cannot complete a normal life cycle The element is part of an essential molecule (macromolecule, metabolite) inside the plant Most elements fall into both categories above (e.g., structural vs. enzyme cofactor) These 17 elements are classified as 9 haramakro(present at > 10 mmol / kg dry wt.) 8 haramikro(< 10 mmol / kg dry wt.) Ada 17 unsurharaesensial yang dibutuhkantanaman

29. Uanruharamikrodengankonsentrasisangatrendah ppm Very low concentrations, but still essential because of specialized roles in metabolism

30. I. Hara Tanaman • Hara Makro / Mikro • Hydroponics allowed us to see what was needed • The necessary nutrients are those the plant can not grow with out • DuaKategori: • 1. Hara Makro (C, O, H, N, S, P, K, Ca, Mg) • Majority of the time used for the main organic compounds • 2. Hara Mikro (Cl, Fe, B, Mn, Zn, Cu, Mo, Ni) • Mostly cofactors for particular enzymes (Fe -> Cytochromes

31. Soils particles are generally negatively charged and so bind positively charged nutrient ions (cations). KTK atau CEC: Kemampuantanahmengikatkation. NH4+, NO3-, Cl-, PO4-2, SO4-2

32. pH tanahmempengaruhiketersediaanharadalamtanah.

33. AKAR Mempunyaipermukaan yang luasuntukpenyerapanhara BuluAkar = Root hairs

34. Buluakar = Root hairs

35. Zone Penyerapanhara: Konsentrasiharamenurunkarenadiserrapakar Zone inidisekitarakartanaman Fig. 5.7

36. Akartanamandanpenyerap[an haradaritanah Akar-akarhalusdanbuluakarmenyerapharadaritanah. Hifamikorizamembantupenyerapanharaolehakar.

37. PertukaranKationantarabuluakartanamandenganpartikelliattanah K+ K+ K+ Clay particle H+ K+ K+ K+ K+ K+ Root hair

38. Mikoriza VAM (Vesicular ArbuscularMycorrhiza) • Di dalamakartanaman • Intercellular mycelium • Intracellular arbuscule • tree-like haustorium • Vesicle with reserves • Di luarakar • Spores (multinucleate) • Hyphae • thick runners • filamentous hyphae • Membentukjaring-jaringhifa yang sangatekstensif

39. Bakterifiksasi Nitrogen Genus: Rhizobium N2 NH4 Supply of electrons

40. Penyerapan ion hara

41. Penyerapanharasecaraaktif Proton pumps establish an electrochemical gradient. Outside cell (positive) Net positive charge Net negative charge Inside cell (negative)

42. KationmemasukibuluakarmelaluisaluranatauKarier

43. Anion memasukibuluakarmelaluiko-transporter.

44. Konsep Kadar Kritis Hara tanaman • Above critical concentration, there is no net benefit (e.g., yield increase) if more nutrient is supplied • Below critical concentration, nutrient level limits growth! • Not shown on diagram: all elements eventually become toxic at very high concentrations

45. Analisisjaringantanamanmenunjukkandefisiensihara

46. Gejaladefisiensimunculkalauharaesensialtidakada (tidakcukup) • Essential because of their metabolic functions • Characteristic deficiency symptoms shown because of these roles • Typical deficiency responses are • Chlorosis: yellowing; precursor to • Necrosis: tissue death • Expressed when a supply of an essential metabolite becomes limiting in the environment • Element concentrations are limiting for growth when they are below the critical concentraion • This is the concentration of nutrient in the tissue just below the level giving maximum growth

47. KurangnyaharaakanberpengaruhnegatifterhadappertumbuhantanamanKurangnyaharaakanberpengaruhnegatifterhadappertumbuhantanaman • Plant responses to limiting nutrients usually very visible: affects yield/growth! • Again, chlorosis and necrosis of leaves is typical • Sometimes straightforward relationship • e.g., in chlorosis (lack of green color), • N: chlorophyll component • Mg: cofactor in chlorophyll synthesis Ctrl - P - N - Fe - Ca

48. REKOMENDASI PUPUK • Tujuan: • Mendugajumlahhara yang dibutuhkanuntukpertumbuhantanaman. • Berdasarkansejarahlahandanpertanaman • Berdasarkanpadaproduksi yang jelekatauperhitunganestimasiserapanharaatanaman. • Based on plant or soil analysis; different labs use different standards so recommendations may differ • Masihbelumtuntas, terutamauntukkehutanan.

49. KUALITAS PUPUK Grade Pupuk: Jaminan persentase minimum hara N, P (P2O5), K (K2O) Additional nutrient contents are separately specified Total weight of bag content Manufacturer Sometimes the filler content and salt index are specified Beberapa material dapat memebntuk asam.

50. PERHITUNGAN PUPUK • Note that the three numbers on the bag are N, P as P2O5, and K as K2O or sometimes KCl • Note that fertilizers do not actually contain P2O5 or K2O • This is an artifact of very old methods of analysis where these nutrients were measured by combustion and ended up as oxides which needed to be weighed. • See the calculations on p. 334, 335, and 336; we will go over these in detail in class