evaluasi produktivitas tanah : aspek bio-kimia mk. stela-smno.fpub.jun2014

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EVALUASI PRODUKTIVITAS TANAH : ASPEK BIO-KIMIA Mk. Stela-smno.fpub.jun2014

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EVALUASI PRODUKTIVITAS TANAH : ASPEK BIO-KIMIA Mk. Stela-smno.fpub.jun2014. ASPEK BIOLOGIS & KIMIA PRODUKTIVITAS TANAH. Pola aliran biomasa pupuk kandang dan sisa panen tanaman di lahan pertanian sangat beragam sesuai dengan praktek budidaya pertanian di daerah iklim basah dan kering . - PowerPoint PPT Presentation

TRANSCRIPT

EVALUASIPRODUKTIVITAS

TANAH :ASPEK BIO-KIMIA

Mk. Stela-smno.fpub.jun2014

Sumber:. http://www.fao.org/docrep/V9926E/v9926e05.htm#TopOfPage

Pola aliran biomasa pupuk kandang dan sisa panen tanaman di lahan pertanian sangat beragam sesuai dengan praktek

budidaya pertanian di daerah iklim basah dan kering.Biasanya semua biomasa akar ( misal, 40% dari total

pertumbuhan tanaman) dan 10-30% dari biomasa tajuk tanaman di-daur-ulang dalam sistem pertanaman semusim.

Where alley cropping and agroforestry are practised, values are more variable, but possible inputs could be very

significant where the trees, from which the litter is taken, are grown away from the annual crops.

ASPEK BIOLOGIS & KIMIA PRODUKTIVITAS TANAH

Sumber:. http://www.fao.org/docrep/V9926E/v9926e05.htm#TopOfPage

Kalau dua-pertiga daun-daun pohon legume dipanen setiap tahun, nilai biomasa seresah ini sangat besar dan kualitasnya lebih baik dibanding dengan jerami sisa panen tanaman semusim lain; biomasa legum

ini sebagai pupuk hijau di-daur-ulang di lahan.

Tree root material is not available for decomposition in the crop field unless it is spatially overlapping (e.g. as an intercrop), in which case the trees will compete

with the crop for soil nutrients, water, light and space.

ASPEK BIOLOGIS & KIMIA PRODUKTIVITAS TANAH

Sumber:. http://www.fao.org/docrep/V9926E/v9926e05.htm#TopOfPage

Produksi biomasa dedaunandari Pohon Multiguna (Young 1989)

Country Land use Tree t/ha/yearMalaysia Plantation Acacia mangium 3.06Philippines Plantation Albizia falcataria 0.18Costa Rica Hedgerow intercropping Calliandra calothyrsus 2.76Philippines Plantation Gmelina arborea 0.14Indonesia (Java) Plantation L. leucocephala, A.

falcataria, Dalbergia latifolia, Acacia auriculiformis

3.00-5.00

Cordia alliodora 2.69Plantation crop C. alliodora + cacao, 6.46

Costa Rica combination Erythrina poeppigiana, 4.27E. poeppigiana + cacao 8.18

Nigeria Hedgerow intercropping Cajanus cajan 4.10Nigeria Hedgerow intercropping Gliricidia sepium 2.30Nigeria Hedgerow intercropping L. leucocephala 2.47Nigeria Hedgerow intercropping Tephrosia Candida 3.07India Plantation L. leucocephala 2.30

Sumber:. http://www.fao.org/docrep/V9926E/v9926e05.htm#TopOfPage

Laju dekomposisi biomasa seresah daun tergantung pd kondisi lingkungannya, terutama suhu dan lengas tanah.

Kedua kondisi lingkungan tanah ini mempengaruhi penghancuran fisik seresah dan menentukan populasi & aktivitas hewan tanah serta fungi tanah yang “makan”

bahan organik tersebut. Decomposition also varies with plant type and age of litter, being

slower for heavily lignified material. The specific properties of litter from different species, and the

generally exponential form of litter decay (the rate of decomposition slowing with time) lead to values that suggest

half-lives of litter ranging from 1 to about 10 years .

ASPEK BIOLOGIS & KIMIA PRODUKTIVITAS TANAH

Sumber:. http://www.fao.org/docrep/V9926E/v9926e05.htm#TopOfPage

Beberapa faktor yg mempengaruhi kecepatan dekomposisi BOT dan siklus hara adalah spesies tanaman, suhu dan

lengas tanah, serta faktor pengelolaan tanaman.

Ada empat cara untuk mengelola residu tanaman: 1. Stubble mulch in which residues are left standing; 2. Surface mulch, where above-ground residues are cut and left on

the top of the soil after harvest; 3. Incorporation by ploughing; and 4. Cut-and-carry, in which surface residue is removed and (if not used

for livestock or thatching, etc.) returned as a surface mulch about planting time for the subsequent crop; this is usually combined with ploughing of below-ground residues.

ASPEK BIOLOGIS DAN KIMIA PRODUKTIVITAS TANAH

Sumber:. http://www.fao.org/docrep/V9926E/v9926e05.htm#TopOfPage

Konstante dekomposisi, k, untuk biomasa jenis legum tropis. Nilai-nilai ini dihitung dnegan persamaan exponential untuk dekomposisi BO

dengan memakai data dalam pustaka ( Juo and Payne 1993) Species Location Mean annual

rainfall Mean annual

temperature °C k/year

Gliricidia sepium Ibadan, Nigeria 1250 23-31 8.48

Flemingia congesta Ibadan, Nigeria 1250 23-31 3.66

Cassia siamea Ibadan, Nigeria 1250 23-31 2.17

Lonchocarpus cyanescems

Ibadan, Nigeria 1250 23-31 8.87

Inga vera El Verde, Puerto Rico

4000 22 1.65

Inga sp. And Erythrina (mixed)

Caracas, Venezuela 1200 20 3.01

Erythrina sp. (mixed with non-legumes)

Caracas, Venezuela 1200 20 3.81

Inga edulis Yurimaguas, Peru 2200 26 0.91

Cajanus cajan Yurimaguas, Peru 2200 26 1.45

Erythrina sp. Yurimaguas, Peru 2200 26 3.72

ORGANISME TANAH YG BERASOSIASI DNEGAN TANAMAN

Bacteria dan NitrogenCropping in dryland regions needs nitrogen to be economically

successful (e.g., Keating et al. 1991). Two sources of nitrogen are from organic matter (Chapter 2, section Soil pores and water characteristics)

and from nitrogen-fixing bacteria associated with plant roots. Bradyrhizobium and Rhizobium species infect plant roots forming galls or nodules, and fix nitrogen from the soil atmosphere directly to the

plants. Locally-adapted, heat-tolerant strains survive from crop to crop in wet-and-dry climates and, whether established by natural colonization or

by inoculation of the crop seed at sowing, they subsequently fix variable quantities of nitrogen.

Kalau infeksi bakteri dapat efektif, bacteria biasanya dapat memfiksasi sekitar 70-100% dari total nitrogen yg digunakan oleh tanaman, proporsi ini lebih rendah kalau ada aplikasi pupuk N anorganik.

Sumber:. http://www.fao.org/docrep/V9926E/v9926e05.htm#TopOfPage

Efek N mineral tanah dan pupuk N terhadap produktivitas N tanaman dan proporsi (P) serta jumlah N-tanaman yg berasal dari fiksasi N2

( Peoples and Craswell 1992)

Sumber:. http://www.fao.org/docrep/V9926E/v9926e05.htm#TopOfPage

Species Location Level Total crop N2 fixed Soil mineral N

(kg N/ha) Fertilizer N (kg N/ha)

N (kg N/ha/crop)

Proportion Amount (kg N/ha/crop)

Groundnut India - 0 196 0.61 120 100 210 0.47 99 200 243 0.42 102

Chickpea Australia 10 (to 120 cm) 114 0.85 97

326 184 0.17 33

0 109 0.80 87 50 110 0.55 60

100 104 0.29 30 Soybean Australia 70 (to 120 cm) 230 0.34 78

260 265 0.06 16

India - 0* 63 0.29 18 100 148 0.26 28

- 0** 89 0.48 43 100 115 0.24 28

ORGANISME TANAH YG BERASOSIASI DG TANAMAN

The extent of the effectiveness of infection of legume crops in the wet-and-dry tropics needs to be surveyed.

Temperate research indicates that nitrogen fixed by bacteria ranges from 20 to 120 kg N/ha in a growing season for annual crops (Table

24). In the semi-arid tropics, amounts of nitrogen fixed per hectare range

from none, where nodulation is ineffective, to 16 kg N in soybean naturally colonized by rhizobia, to 84 kg N when inoculated.

Fiksasi Nitrogen pada kedelai dan kacang-tanah sebesar 50-70 kg N/ha/musim tanam dilaporkan di Senegal (Gigou et al. 1985).

Bakteri fiksasi Nitrogen berasosiasi dnegan pohon legume dapat memfiksasi sejumlah nitrogen seperti kedalai dan kacangtanah.

Sumber:. http://www.fao.org/docrep/V9926E/v9926e05.htm#TopOfPage

Fiksasi Nitrogen oleh pohon dan belukar. Values are per growing season or per year unless the number of months is given in brackets

(Young, 1989 ; Peoples and Craswell 1992)

Sumber:. http://www.fao.org/docrep/V9926E/v9926e05.htm#TopOfPage

Species N fixation (kg N/ha/year) Acacia albida 20 Acacia mearnsii 200 Allocasuarina littoralis 220(?) Casuarina equisetifolia 60-110 Coffee + Inga spp. 35 Coriaria arborea 190 Erythrina poeppigiana 60 Gliricidia septum 13 Inga jinicuil 35-40 Inga jinicuil 50 Inga jinicuil 35 Leucaena leucocephala 100-500 Leucaena leucocephala (in hedgerow intercropping)

75-120

Leucaena leucocephala 100-13 (6)

ORGANISME TANAH YG BERASOSIASI DG TANAMAN

Fungi, Algae dan Hara

Berbagai jenis fungi membantu penyerapan hara oleh akar tanaman, terutama phosphorus. Banyak jenis fungi hidup

berasosiasi dengan akar tanaman.

One group, vesicular arbuscular micorrhizal fungi (VAM), form both vesicles and arbuscules (knot-like structure) on

the surface and within the root. They also colonize soil animals including earthworms and

woodlice.

Sumber:. http://www.fao.org/docrep/V9926E/v9926e05.htm#TopOfPage

ORGANISME TANAH YG BERASOSIASI DNEGAN TANAMAN

Mikroba ini banyak dijumpai dalam topsoil hingga kedalaman 10 cm (Habte 1989). Mereka ini membantu penyerapan hara, terutama

fosfor dari tanah yang miskin fosfor. Mereka ini juga menyediakan proteksi bagi tanaman inangnya, keberadaannya dapat menurunkan

kolonisasi oleh patogen. Ellis et al. (1985) also found that wheat plants inoculated with VAM were more drought-tolerant than plants without VAM. Importantly,

comparisons of conventional cropping systems using inorganic fertilizers and herbicides with organic systems not using herbicides have found much higher levels of infection of crop roots by these

beneficial fungi in the organic system (Ryan et al. 1994).

Pengelolaan organisme tanah yg bersifat asosiatif dan menguntungkan menjadi bagian penting dari sistem pertanaman yg lestari.

Sumber:. http://www.fao.org/docrep/V9926E/v9926e05.htm#TopOfPage

Frequency (%) fungi VAM dalam macro-invertebrata tanah yang diambil dari ekosistem alam dan pertanian di Ohio (data are combined from 1986 and 1987

samplings) (Source: Rabatin and Stinner 1989)

Sumber:. http://www.fao.org/docrep/V9926E/v9926e05.htm#TopOfPage

Taxa Ekosistem

Conventional tillage maize

No-tillage maize

Pasture Old field

Lumbricidae (earthworms)

25.0 83.3 50.0 75.0

Isopoda (woodlice)

100.0 35.7 64.7 36.8

Carabidae (ground beetles)

2.1 19.8 14.5 12.8

ORGANISME TANAH YG BERASOSIASI DNEGAN TANAMAN

GULMA, HAMA & PENYAKIT TANAMAN

Gulma, hama dan penyakit semuanya bersaing dnegan tanaman atau secara langsung mereduksi vigour tanaman. Banyak hama dan

penyakit bersifat “soil-borne”.

Weed life-cycles depend on replenishment of the soil seed bank and survival of the seeds against natural decay, predation by soil animals

and depletion by human management, particularly cultivations.

Ecological weed control thus aims to minimize recruitment of new seed into the soil as a long-term strategy as well as trying to reduce

artificially the size of the weed seed bank in the soil.

Sumber:. http://www.fao.org/docrep/V9926E/v9926e05.htm#TopOfPage

KETERSEDIAAN HARA DALAM TANAH

HARA ANORGANIKHara anorganik dalam tanah dapat berbentuk ion dan mineral misal. Oksida-oksida, silikat dan fosfat; keduanya dijerap pada permukaan

partikel liat dan bahan organik , dan ada dalam larutan tanah. Sebagian besar dari hara, terutama nitrogen, ditemukan dalam bahan organik tanah, sehingga BOT dan organisme tanah sangat penting bagi

per-hara-an tanah.

Clay particles, because of their crystalline structures, carry an inherent electrical charge. This results in attractive forces (mainly van der Waals forces) and repulsive forces (electrostatic forces) which give clay species their particular characteristics.

The inherent surface charge also causes a layer of associated ions to align next to the solid particles forming a so-called diffuse double layer because it consists of a

relatively inexchangeable layer (the Stem layer) closest to the surface of the particle and an outer, readily exchangeable layer, of varying thickness, called the diffuse

layer. Sposito (1984) explains this more fully.

Sumber:. http://www.fao.org/docrep/V9926E/v9926e05.htm#TopOfPage

Penjerapan (Adsorption) merupakan akumulasi neto materi pada ruang antara fase padatan dan fase cairan. Ion-ion yang mudah

ditukar dijerap dg kekuatan “lemah” pd permukaan koloid tanah dan mudah dapat digantikan dnegan jalan pencucian menggunakan larutan

elektrolit. KTK tanah merupakan jumlah mole ion yg dijerap dan dapat

digantikan dari suatu unit massa tanah; ion-ion seperti ini lazim disebut “ion mudah ditukar”.

Sposito (1984) notes that 'Much controversy exists over the surface chemical significance of ion exchange capacities'. The maximum

surface charge measurement indicates a soil's potential to adsorb ions while its actual capacity, which is more relevant agriculturally, has a

lesser value. Table 28 gives representative cation exchange capacities (CECs) for selected soil orders. It is notable that though the CEC of each

order ranges widely, the predominant soils in wet-and-dry climates have low CECs.

Sumber:. http://www.fao.org/docrep/V9926E/v9926e05.htm#TopOfPage

KETERSEDIAAN HARA DALAM TANAH

Nilai-nilai KTK lapisan tanah permukaan (molC/kg) (: Sposito 1984)

Sumber:. http://www.fao.org/docrep/V9926E/v9926e05.htm#TopOfPage

ORDO TANAH KTKAlfisols 0.1 2 ± 0.08Aridisols 0.16 ± 0.05Entisols 0.13±0.06Histosols 1.4±0.3Inceptisols 0.19±0.17Mollisols 0.22±0.10Oxisols 0.05±0.03Spodosols 0.11 ±0.05Ultisols 0.06 ±0.06Vertisols 0.37 ± 0.08

KETERSEDIAAN HARA DALAM TANAH

Proporsi kation tukar dalam KTK beragam dengan pH tanah; proporsi basa-tukar yg mudah tersedia menurun dari sekitar 1 pada pH 8 dan 0.5 pada pH 6 menjadi sekitar 0.2 pada pH 4.5. Pada kondisi pH kurang dari 6 terjadi peningkatan ion-

ion aluminium yang dapat bersifat toksik.

The electrical conductivity and CEC of a soil are related to its clay content (e.g., Rhoades 1990a). Similarly, because of the electrical

charge of the clay particles, a high but variable percentage of the soil organic matter is bound to them. It may be as high as 90% ; and there

are the two postulated main ways that organic matter is bonded to clay. These are weak anion exchange and strongly-held ligand

exchange which is a form of chemical bonding.

Sumber:. http://www.fao.org/docrep/V9926E/v9926e05.htm#TopOfPage

KETERSEDIAAN HARA DALAM TANAH

Proporsi C-organik dalam tanah yang berbentuk Kompleks Liat-Organik.

1 Defined as the material sinking when the soil was ultrasonically dispersed in an organic liquid of density 2 g/cm3.

Sumber:. http://www.fao.org/docrep/V9926E/v9926e05.htm#TopOfPage

Percent organic carbon in soil

Percent soil carbon in clay-organic complex1

Podzol 1.5 18Solonized brown soil 1.5 77

Grey clay soil 1.1 91Terra rossa 2.8 82Groundwater rendzina

5.4 69

Black earth 1.8 82Krasnozem 4.9 90Red brown earth 2.5 66

Liat dan bahan organik tanah mempunyai muatan listrik, dan keduanya mempunyai sumbangan besar dalam menentukan

kemampuan tanah menahan hara-tersedia dan stabilitas struktur tanah.

Pieri (1992) mengusulkan bahwa stabilitas struktur tanah (untuk tanah-tanah di Afrika yg ditelitinya) dapat

dideskripsikan dengan nilai kritis S lebih besar dari 9, dimana S adalah rasio bahan organik dengan (liat plus

debu) , dinyatakan dalam persentase.

Sumber:. http://www.fao.org/docrep/V9926E/v9926e05.htm#TopOfPage

KETERSEDIAAN HARA DALAM TANAH

Diagram jembatan anionik : Pertukaran Anion. R adalah Koloid humik poli-anionik humic colloid.

Sumber:. http://www.fao.org/docrep/V9926E/v9926e05.htm#TopOfPage

Diagram jembatan anion: Pertukaran ligand. R adalah koloid humik poli-anionik.

Sumber:. http://www.fao.org/docrep/V9926E/v9926e05.htm#TopOfPage

Tingkat kritis BOT untuk mempertahankan stabilitas fisik struktur tanah (Pieri 1992)

Sumber:. http://www.fao.org/docrep/V9926E/v9926e05.htm#TopOfPage

Akar tanaman menyerap hara anorganik dari larutan tanah (kecuali legumes, yang mampu memfiksasi nitrogen langsung dari udara

tanah). Unsur hara dapat tersedia bagi tanaman kalau ia berbentuk ion bebas dan berada dalam zone perakaran.

Ion-ion hara dalam tanah bergerak memasuki zone akar melalui pergerakan air tanah, dan ion hara memasuki tanaman melalui

evapotranspiration.Diffusion along concentration gradients is important for less-mobile ions such as phosphorus, particularly where soil solution concentrations are

weak and root densities are high (i.e., the transport path is short). Sposito (1984) and others give calculated values for the diffusivity of nutrients.

Diffusion times range from 1 day for an ion to move 3 mm (which is comparable with the time it would take to move by convection in the

mass flow of water) for nitrate to about 200 days for potassium, magnesium and molybdenum, and to thousands of days for other

nutrients. Sumber:. http://www.fao.org/docrep/V9926E/v9926e05.htm#TopOfPage

KETERSEDIAAN HARA DALAM TANAH

pH rendah mempengaruhi akar tanaman secara langsung karena efek konsentrasi H+ thd integritas membran sel akar dan kapasitas

pertukarannya. Kemasaman jug mempengaruhi akar secra tidak langsung melalui dua cara. Ia mengubah ketersediaan ion dalam larutan tanah (membuat

spesies Al tersedia yg toksik bagi tanaman plants). Ia juga mempengaruhi mineralisasi melalui proton yg bersaing dengan cations

untuk mendapatkan ligand yg terlarut dan gugus fungsional pd permukaan yg bermuatan.

Soil pH also affects micro-organisms, and thus the speed of transformations, for example, those between nitrate and ammonium.

Poor plant growth on acid soils may thus be caused directly by hydrogen ions, by toxicities of aluminium or manganese, or through

deficiencies of calcium, magnesium, potassium, phosphorus, nitrogen or trace elements.

Sumber:. http://www.fao.org/docrep/V9926E/v9926e05.htm#TopOfPage

KETERSEDIAAN HARA DALAM TANAH

Chase et al. (1989) describe these relationships for sandy Sahelian soils. Variation in pH across distances of 15 m can be as much as pH 4.5 to 7.5, with associated decreases in

aluminium and hydrogen ions, and increases in crop productivity.

Nilai kritis pH yang mempengaruhi pertumbuhan tanaman ternyata beragam dnegan jenis tanaman, cultivar dan tipe

tanahnya.

Tingkat kritis ini dapat sebesar pH 5 - 5.5 untuk jenis tanaman yg tidak toleran Al , tetapi jenis tanaman lainnya

yang toleran mempunyai nilai kritis pH 3.9 - 4. Sumber:. http://www.fao.org/docrep/V9926E/v9926e05.htm#TopOfPage

KETERSEDIAAN HARA DALAM TANAH

Bahan organik tanah berhubungan dengan partikel (mineral) tanah secara kimiawi dan secara fungsional.

BOT berhubungan erat dengan berbagai problematik biologis dan ketersediaan hara dalam tanah.

Rates of loss of organic matter independent of erosion tend to be slow, but important as they are cumulative.

Pada kondisi lingkungan lahan-kering di Afrika Barat, laju kehilangan BOT dapat mencapai 2-4% per

tahun. Sumber:. http://www.fao.org/docrep/V9926E/v9926e05.htm#TopOfPage

INDIKATOR PROBLEMATIK BIOLOGIS DAN HARA

TABLE 31. Annual rate of organic matter loss measured in the field in the savannah area (Source: Pieri 1992)

Sumber:. http://www.fao.org/docrep/V9926E/v9926e05.htm#TopOfPage

INDIKATOR PROBLEMATIK BIOLOGIS DAN HARA

Place and source Dominant rotation Clay + silt(%)

(0-20 cm)

Annual rate of loss Notes k (%) No. of years

Burkina Faso Ploughed

Sorghum monocropping

12 1.4 10 No fertilizer

Sorghum monocropping

12 1.9 10 Low rate manure

Sorghum monocropping

12 2.6 10 High rate manure

Sorghum monocropping

12 2.2 10 m + crop residues

Cotton-cereal 19 6.3 15 Much erosion

Cameroun Cotton-cereal 17 3.2 5 No fertilizer

Cotton-cereal 17 2.9 5 Fertilizer

Cotton-cereal 17 2.5 5 Fertilizer + kraal

Côte d'Ivoire Cotton-cereal - 2.6 5 Low rate manure

Cotton-cereal - 2.3 3 Low rate manure

Cotton-cereal - 0.4 3 Improved fallow

Larson dan Pierce (1991) mengusulkan bahwa seperangkat data yg dikumpulkan secara analitik sangat penting untuk

memantau kelestarian tanah. They include two measures of organic matter among the ten

attributes that they consider essential (Table 32). Their concept of requiring agreed minimum data sets is

consistent with the approach to assessing sustainability .

Kalau seperangkat data tersebut telah diperoleh (Larson and Pierce 1991), setiap atribut tanah ditentukan dengan waktu referensi tertentu (T0) dan perubahan kondisi tanah dapat diukur selama periode waktu tertentu (T1), misalnya 1 – 10

tahun.

Sumber:. http://www.fao.org/docrep/V9926E/v9926e05.htm#TopOfPage

INDIKATOR PROBLEMATIK BIOLOGIS DAN HARA

TABLE 32. Soil attributes and standard methodologies for their measurement to be included as part of a minimum data set (MDS) for

monitoring soil quality (Source: Larson and Pierce 1991)

Sumber:. http://www.fao.org/docrep/V9926E/v9926e05.htm#TopOfPage

Soil attribute MethodologyTotal organic carbon Dry or wet combustionLabile organic carbon Digestion with KCINutrient availability Analytical soil testpH Glass electrode-calomel electrode pH meter

Electrolytic conductivity Conductivity meterTexture Pipette or hydrometer method

Plant-available water capacity Determined in field best or from water desorption curve

Structure Bulk density from intact soil cores field measured permeability of Ksat

Strength Bulk density or penetration resistance

Maximum rooting depth Crop specific - depth of common roots or standard

Pengukuran C-organik tanah secara langsung dianggap tidak-efektif biaya dan tidak informatif.

It is more likely that surrogate measures are adequate and, if sufficiently simple and cheap, have some likelihood of being

used. Pieri (1992) suggests that a bleached (possibly brittle) soil

surface and plant deficiency symptoms are useful surrogates for loss of organic matter, low CEC and soil nutrient imbalances.

Kehilangan BOT biasanya dibarengi dengan degradasi struktur tanah, indikator-indikator seperti turbiditas air permukaan (mis. Air

sungai) dianggap sangat berguna.

Sumber:. http://www.fao.org/docrep/V9926E/v9926e05.htm#TopOfPage

INDIKATOR PROBLEMATIK BIOLOGIS DAN HARA

Hara Mineral dan Problematik Kesuburan Tanah (Source: Pieri 1992)

Sumber:. http://www.fao.org/docrep/V9926E/v9926e05.htm#TopOfPage

INDIKATOR PROBLEMATIK BIOLOGIS DAN HARA

General problems Signs of simple problems Where they occur Probable causes

Limitation of nutrient supply to crops· Nutrient imbalanceDeficiency in organic matter

Bleaching and destruction of soil surface

Senegal, Niger, Burkina Faso, Mali

Insufficient return of crop residuesAccelerated mineralization of dry matterToo little fertilizer

Defisit N (S) N (S) deficiency in cereals, legumes and cotton

Throughout area Too little N (S) applied in fertilizers or manures. High C/N ratioVery little N fixationLeaching of nitrate

K-Ca-Mg deficit K deficiency, Al toxicity Frequent K deficiency in cottonAl toxicity in groundnut and cotton (Senegal)

Severe leaching of Ca, Mg, K.Fertilizers low in Ca, Mg, K.

· Low buffer capacityProgressive drop in CEC

Loss of fine mineral and organic soil particles

Senegal, Mali, Cote d'Ivoire, Burkina Faso, Niger, Chad

Poor erosion controlRapid mineralization

Acidification Senegal, N Cote d'Ivoire, Burkina Faso, Chad

NO3/Ca + Mg leachingFertilizers too low in Ca, MgToo little or no liming

Tanah-tanah Marjinal

Nutrient deficiencies Senegal, N Togo, S Mali, Burkina Faso

Land shortagePoor cultivation

Indikator defisiensi hara meliputi : warna (mis. Kemerahan unt defisiensi kalium); pucat (gejala umum, tetapi

merupakan gejala khusus defisiensi N); daun-daun kecil dan tanaman kerdil.

Other symptoms, such as leaf curling and accelerated dropping of older leaves, may also be helpful but might

equally indicate water deficits.

There are several publications with photographs of nutrient deficiencies; these, however, might require further tailoring

to specific combinations of crops and soils.

Sumber:. http://www.fao.org/docrep/V9926E/v9926e05.htm#TopOfPage

INDIKATOR PROBLEMATIK BIOLOGIS DAN HARA

Gejala efek kemasaman tanah dicirikan oleh tanaman kerdil, muka tanah bersih vegetasi, dan jenis-jenis gulma yg toleran

asam tumbuh lebih baik. Salinitas juga dicerminkan oleh perubahan vegetasi seperti

pohon mati tanpa alasan yg jelas atau meningkatnya populasi herba yg toleran garam.

Other symptoms of salinity include: waterlogged or bare soil; livestock congregating and licking the soil surface for

salt; visible salt crystals; the smell of salt; and clear catchment water because salt settles sediment.

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INDIKATOR PROBLEMATIK BIOLOGIS DAN HARA

Pengelolaan unt Memelihara Biologi dan Hara Tanah

The aim of management should be to create balanced organic matter and mineral budgets. It should ensure that, over several years (a

complete crop rotation), soil organic matter is not depleted and that nutrients added equal or exceed those removed by cropping or lost in

various ways.

When managing organic matter farmers should recognize that the effects of animal and human manure, sewage sludge and plant

residues last longer than those of green manure crops.

Manfaat pupuk hijau biasanya berlangsung selama satu atau dua musim, karena bahan organik ini dimasukkan ke tanah sebelum dewasa (tua) dan berlignin. Efek jangka panjang bahan organik

terhadap organisme tanah juga ada. Sumber:. http://www.fao.org/docrep/V9926E/v9926e05.htm#TopOfPage

INDIKATOR PROBLEMATIK BIOLOGIS DAN HARA

Aspek-aspek yg dipertimbangkan dalam memelihara dan ameliorasi biologi tanah dan hara tanah

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Pemeliharaan: Pencegahan Degradasi1. Pemilihan Tanaman· Preference for rotations and intercropping with several species, as for Table 19· Inclusion of legume in rotation

2. Praktek Budidaya Tanaman· Aplikasi pupuk anorganik untuk menjaga neraca hara yg netral· Konservasi seresah tanaman · Aplikasi kotoran manusia dan hewan· Incorporation of organic wastes from industry and cities· Olah tanah minimum· Pengelolaan hayati hama dan gulma· Mengurangi laju pengasaman melalui pemilihan jenis tanaman, pengelolaan seresah dan pupuk.

3. Pengelolaan Air· Water harvesting· Minimization of salinity, if a problem is likely, through seasonal leaching and other practices

Aspek-aspek yg dipertimbangkan dalam memelihara dan ameliorasi biologi tanah dan hara tanah

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INDIKATOR PROBLEMATIK BIOLOGIS DAN HARA

Ameliorasi untuk mengontrok kerusakan :

1. Ketidak-seimbangan dan defisiensi hara· Berdasarkan gejala visual, aolikasi pupuk anorganik· Mengubah pola tanam untuk mengurangi efek kemasaman

2. Degradasi permukaan tanah melalui kehilangan BOT, erosi tanah oleh air dan angin :

Aplikasi bahan organik berupa limbah organik, mulsa, tanaman penutup tanah dll.

Pola dan Pergiliran Tanaman mempengaruhi ketersediaan hara tanah.

Diversitas pertanaman meningkatkan jumlah dan ragam organisme tanah dan mengurangi hama dan penyakit.

Soil acidification and salination are extreme cases of nutrient imbalance and, unlike other deficiencies, cannot be corrected simply

by adding mineral fertilizers.

Teknik pengelolaan tanah unt mengurangi asidifikasi: (a) Mengurangi produksi proton dengan jalan meminimumkan pencucian nitrat

(problem khusus di daerah iklim musimaan basah-kering); (b) Menghindari penggunaan pupuk ammonium dan mengurangi akumulasi bahan

organik; (c) Mengapur tanah.

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INDIKATOR PROBLEMATIK BIOLOGIS DAN HARA