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Presentasi berjudul: "PRINSIP-PRINSIP MANAJEMEN KESUBURAN TANAH."— Transcript presentasi:

Bahan Kajian MK. Manajemen Kesuburan Tanah Diarikan soemarno - jursntnhfpub - Sept 2013

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.

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

Large-scale: Treating the entire field as one management unit. SEDERHANA DAN TEKNOLOGI TEPATGUNA Presisi operaisonal relatif rendah. Tidak memperhitungkan variabilitas lahan dan kandungan haranya. Memerlukan sedikit instrumentasi dan latihan teknologi Produksi tidak merata dan potensi pencemartan lingkungan

7 SEKALA MEDIUM. Medium-scale: Sub-dividing the field into two or more management units requiring different applications of fertilizer, pesticides, and irrigation. Biasanya dipraktekkan atas dasar intuitif Memungkinkan penerapan standar lapangan Based on soil types, drainage characteristics, empirical observation, and ease of boundary delineation Efisiensi lebih baik dan pencemaran lingkungan lebih sedikit

8 SEKALA KECIL. Small-scale (precision): A system in which infinitesimal land management units occur within a single field. Menggunakan GPS dan mengembangkan basis-data elektronik untuk tanah dan tanaman Memerlukan penerapan beragam teknologi dan peralatannya Lebih praktis untuk komoditi tanaman yang nilai ekonominya tinggi

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.

Over-riding guide: Take a sample so that it represents what it is intended to represent Kedalaman lapisan bajak (traditional ag) At 30 cm (~1 ft) increments; alternate 30 cm increments Horison tanah untuk sistem yang masih utuh Tipe tanah Sampel komposit terdiri atas 5-20 sub-sample untuk setiap sampel analisis Hara setiap tahun, status garam setiap tahun.

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
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
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: M HCl = 0.03 M NH4F (for acidic soils) Mehlich 1: 0.05 M HCl 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 M ammonium nitrate M NH4F M HNO 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.


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.


25 Bagaimana tanaman memperoleh dan menggunakan hara?
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 Ada 17 unsur hara esensial yang dibutuhkan tanaman
Apa definisi unsur hara “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 hara makro (present at > 10 mmol / kg dry wt.) 8 hara mikro (< 10 mmol / kg dry wt.)

29 Uanru hara mikro dengan konsentrasi sangat rendah
ppm Very low concentrations, but still essential because of specialized roles in metabolism PP05T012.jpg

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 Dua Kategori: 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: Kemampuan tanah mengikat kation. PP05050.jpg NH4+, NO3-, Cl-, PO4-2, SO4-2

32 pH tanah mempengaruhi ketersediaan hara dalam tanah.

33 Mempunyai permukaan yang luas untuk penyerapan hara
AKAR Mempunyai permukaan yang luas untuk penyerapan hara Bulu Akar = Root hairs

34 Bulu akar = Root hairs

35 Konsentrasi hara menurun karena diserrap akar
Zone Penyerapan hara: Konsentrasi hara menurun karena diserrap akar Zone ini di sekitar akar tanaman PP05070.jpg Fig. 5.7

36 Akar-akar halus dan bulu akar menyerap hara dari tanah.
Akar tanaman dan penyerap[an hara dari tanah Akar-akar halus dan bulu akar menyerap hara dari tanah. Hifa mikoriza membantu penyerapan hara oleh akar.

37 Pertukaran Kation antara bulu akar tanaman dengan partikel liat tanah
Clay particle H+ K+ K+ K+ K+ K+ Root hair

38 Mikoriza VAM (Vesicular Arbuscular Mycorrhiza)
Di dalam akar tanaman Intercellular mycelium Intracellular arbuscule tree-like haustorium Vesicle with reserves Di luar akar Spores (multinucleate) Hyphae thick runners filamentous hyphae Membentuk jaring-jaring hifa yang sangat ekstensif

39 Bakteri fiksasi Nitrogen
Genus: Rhizobium N NH4 Supply of electrons

40 Penyerapan ion hara

41 Penyerapan hara secara aktif
Proton pumps establish an electrochemical gradient. Outside cell (positive) Net positive charge Net negative charge Inside cell (negative)

42 Kation memasuki bulu akar melalui saluran atau Karier

43 Anion memasuki bulu akar melalui ko-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 Analisis jaringan tanaman menunjukkan defisiensi hara

46 Gejala defisiensi muncul kalau hara esensial tidak ada (tidak cukup)
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 Kurangnya hara akan berpengaruh negatif terhadap pertumbuhan tanaman
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 Menduga jumlah hara yang dibutuhkan untuk pertumbuhan tanaman.
REKOMENDASI PUPUK Tujuan: Menduga jumlah hara yang dibutuhkan untuk pertumbuhan tanaman. Berdasarkan sejarah lahan dan pertanaman Berdasarkan pada produksi yang jelek atau perhitungan estimasi serapan hara atanaman. Based on plant or soil analysis; different labs use different standards so recommendations may differ Masih belum tuntas, terutama untuk kehutanan.

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

Starter: with the seed, low amounts Broadcast: spread evenly over the land (lowest efficiency) Tidak dekat akr tanaman, dapat memberi makan gulma Fiksasi P dalam tanah Mengapa dilakukan? Cara yang praktis - pastures, etc. Build up stocks in low-fertility soils Mudak dan murah Cara terbaik menambahkan pupuk kepada tanaman yang telah mulai tumbuh

52 TEKNIK APLIKASI UPUPK. Deep banding ; Dibenamkan ke tanah
Kedalaman cm, misalnya pupuk anhydrous ammonium Penempatan pupuk pada lokasi yang dapat dijangkau oleh akar tanaman Biaya mahal. Split Application (Aplikasi ganda, tidak sekaligus) Aplikasi pupuk dua hingga tiga kali Terutama pupuk N, kandungan hara tersedia dalam tanah akan kembali seperti semula dalam waktu 4-12 bulan Menyesuaikan dnegan irama penyerpaan hara tanaman Waktunya kritis

53 .KAPAN APLIKASI PUPUK? Sumbangan N-tersedia dalam tanah (dari pupuk) sudah habis pada Juli-Agustus NH4 + NO3 dalam tanah Aplikasi pupuk sekaligus Sumbangan N-tersedia dalam tanah (dari pupuk) masih ada hingga Nopember Aplikasi pupuk dua-kali

Pemupukan P, K,Mg dan hara lainnya dapat menjaga ketersediaan hara tanah dalam jangka panjang, tetapi tidak demikian halnya dnegan nitrogen Hara ter-sedia dalam tanah N tersedia dalam tanah mudah hilang Tahun

Side dressing: setelah tanaman tumbuh Point Injector fertilization: using a rod to make a hole, put fertilizer deep near plant. Dollop or tree tablet principle. Fertigation: pupuk ditambahkan bersama dengan air irigasi: Tidak sama dnegan aplikasi daun. Obviously require irrigation equipment; not normal for forests or range soils Sangat efisien Biayanya mahal

56 APLIKASI PUPUK DUAN Aplikasi pupuk melalui daun (Foliar application) Bertujuan untuk penyerapan hara lewat daun Seringkali dilakukan untuk mensuplai unsur mikro, kalau diberikan melalui tanah akan mengalami imobilisasi hara Memerlukan bahan pembasah dan bahan perekat Respon tanaman cepat

57 .EFISIENSI PUPUK Didefinisikan sebagai persentase pupuk yang secara aktual digunakan oleh tanaman; atau diukur dalam bentuk hasil tanaman dan keuntungan Generally 30-70% for N, 5-30% for P, 50-80% for K in crops, according to the book (sounds high) Generally 5-40% for N, P, and K in trees, counting only what is in trees at any one time However, trees recycle nutrients, and forest floor contents can be re-used Tidak mudah menilai dalam persentase.

58 .EFISIENSI PUPUK Mengapa efisiensi pupuk relatif rendah?
Imobilisasi oleh mikroba tanah "Fixation“ P dalam tanah Jenis hara keliru Waktu aplikasi pupuk tidak tepat Dosis pupuk tidak tepat Too low feeds microbes, which are most efficient competitors Too high in the case of N causes nitrate leaching losses


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