evaluasi kesub tanah.pdf

MANAJEMEN KESUBURAN TANAH

Semester Ganjil 2014/2015Semester Ganjil 2014/2015EHN (5 September 2014)

Materi 6: Evaluasi Kesuburan Tanah

Hari Jam Ruang Kelas

Senin 13:20 - 15:00 TNH-A2 C

8/9 15/9 22/9 29/9 6/10 13/10 20/20EHN EHN EHN EHN EHN EHN EHNK-10 K-11 K-12 K-13 K-14 K-15 K-16SRU SRU SRU SRU SRU SRU SRU

07:30 - 09:10 TNH-A2 J

9/9 16/9 23/9 30/9 7/10 14/10 21/10EHN EHN EHN EHN EHN EHN EHNK-10 K-11 K-12 K-13 K-14 K-15 K-16SRU SRU SRU SRU SRU SRU SRUSelasa SRU SRU SRU SRU SRU SRU SRU

11:00 - 12:40 TNH-A2 G


Kamis 11:00 - 12:40 TNH-A1 M


Soil fertility evaluation techniques The soil fertility evaluation techniques are broadly grouped

into biological visual symptoms of nutrient deficiency or toxicity, plant analysis plant analysis soil analysis

Biological methods Field trial Pot culture method Neubaver seedling method Aspergillus niger method Aspergillus niger method Soil plaque method

Biological methods: Field trial The most direct way of diagnosing the nutrient status of a soil the effect of the additional amounts of the nutrients in the

form of fertilizers applied to the soil on the growth of the cropis measured.Fertilizer nutrients in graded doses are applied to statistically Fertilizer nutrients in graded doses are applied to statisticallylaid out plots in a fairly homogeneous field.

Yield is the main criterion for assessing the nutrientrequirement of the crops in that soil.

Biological methods: Field trial Broad generalization can be made from the field trials

regarding the kind and quantity of nutrients needed foroptimum yield of crop or crops.

But the effect is very much location and situation specificand is dependent on climatic condition. But this is the onlyand is dependent on climatic condition. But this is the onlydirect method.

Field trial is expensive and time consuming and also thegrowth conditions cannot be fully controlled.

Biological methods: Pot culture The principle of pot culture method is the same as in the

field trials, except that plants are grown in small volume ofsoil in pots or other containers under controlled conditions,e.g. in a glasshouse / greenhouse.

Comparative growth or yield of crops and uptake of plant Comparative growth or yield of crops and uptake of plantnutrients from the treated and untreated portions of the soilare usually taken as indices of nutrient deficiencies.

Biological methods: Pot culture In translating the results of pot trials to the field, the field

conditions must be kept in view. The limitations of pot culture methods are preferential root

growth, limited volume of soil and problems encountered inthe packing of the soil in the pots for simulation of naturalthe packing of the soil in the pots for simulation of naturalfield conditions

Biological methods: Neubaver seedling It is based on the principle, of intensive uptake of nutrient

elements by growing a large number of seedlings on a smallquantity of soil.

As a result, the soil is exhausted of the available nutrients. The entire plant is then analysed for the uptake. The entire plant is then analysed for the uptake.

Biological methods: Aspergillus niger Aspergillus niger, a fungus, is a biological indicator of available

K, P and Mg in soils. In this method small quantity of soil (2.5g) in liquid culture

medium is inoculated with a suspension of Aspergillus nigerspores and incubated for 4 days.spores and incubated for 4 days.

Biological methods: Aspergillus niger A thick pad of mycelium grows on the surface of the

medium. The weight of the dry mycelium and the content of the K

absorbed from the soil can be used to determine deficiencyor sufficiency of K.or sufficiency of K.

The amount of K extracted in the mycelium comparesfavourably with the content of exchangeable K of the soilunder investigation

Biological methods: Soil plaque colonies of Azotobacter grow luxuriantly on soil plaques if

suitable energy materials are provided, and also observed aclose correlation between the limiting factors (say nutrients)for Azotobactor and those for growing plants.

On this basis, a soil plaque technique has been developed for On this basis, a soil plaque technique has been developed forthe study of mineral deficiency in soil.

Biological methods: Soil plaque A small portion of soil with sucrose is inoculated with

Azotobactor and incubated. If the soil, is deficient in potassium or phosphorus, the

colonies of the orgnism will not develop. In the presence of either phosphorus or potash or both In the presence of either phosphorus or potash or both

colonies indicates the degree of deficiency. This technique has been successfully used to indicate the

availability of potassium and phosphorus.

Use of visual symptoms of nutrientdeficiency or toxicity Depending on the mobility of plant nutrients in plants, the

deficiency symptoms are first developed in the lower orupper parts of the plants.

On the basis of the mobility, the major, plant nutrients areclassified as followsclassified as follows Plant nutrients showing deficiency symptoms on older or lower

leaves (nutrients being highly mobile) are N, P, Mg, K and Zn. Plant nutrients showing deficiency symptoms on younger leaves

or bud leaves (nutrients less mobile) are Ca, B, Cu, Mn, S, andFe.

Typical deficiency symptoms developed bythe various essential plant nutrients Nitrogen

A yellow or pale green colour of leaves. Drying up of bottom leaves. Short plant height.

Phosphorus Phosphorus Leaves developing red and purple colours. Slow growth and late maturity. Lower leaves becoming dry, developing purple-colour between

veins. Leaf petioles developing purple colour

Typical deficiency symptoms developed bythe various essential plant nutrients

Potassium Bottom leaves scorched or burned on margins and tips. Leaves

thicken and curl. Deficiency first develops in the wet portion of the field.

Calcium Young leaves of the terminal bud develop a wrinkled appearance Young leaves of the terminal bud develop a wrinkled appearance

and dieback at the tips and margins. Stalk finally dies at the terminal bud.

Iron Young leaves chlorotic, principal veins green, stalks short and

slender. Die-back or death of young growing tissues and rosetting

appearance.

Typical deficiency symptoms developed bythe various essential plant nutrients Manganese

Spots of dead tissue scattered over the young leaves. Smallest veins tend to remain green producing a checkered or

reticulated effect.

Zinc Zinc Yellow stripping of the leaves between the veins. The older leaves die. The plants severally dwarfed.

Typical deficiency symptoms developed bythe various essential plant nutrients Boron

Young leaves of the terminal bud becoming light green at thebases, with final break down.

In later growth, leaves become twisted, stalks finally die atterminal bud. Browning of curd and lesions in pith incauliflower.cauliflower.

Copper Young leaves permanently wilted without spotting or marked

chlorosis. Yellowing and chlorosis of normal green leaves. In grains, is called white tip or yellow tip disease and leaves

dwarfed or distorted.

Typical deficiency symptoms developed bythe various essential plant nutrients Molybdenum

Lower leaves (of tomato} showing mottling,necrosis and curlingof leaf edges.

In oats, leaves bend backward, later break at the affected areaswith necrosis.with necrosis.

Chlorine Leaves display symptoms of wilting of leaf blade tips, chlorosis,

bronzing and necrosis in the areas proximal to the wilting.

Soil analysis method the basic principle underlying the soil analysis method is to

determine the plant nutrient resources of a soil by chemicalanalysis.

Since the total nutrient content, like the total P2O5 contentof surface soil does not give a clear picture of the amount ofof surface soil does not give a clear picture of the amount ofnutrients available to the growing plants, efforts have beenmade to extract and analyse the portion of plant nutrientswhich is available to plants.

Soil Analysis Components

Sampling Chemical analyses Interpretation and recommendations

Steps Sample Collection (Greatest Source of Error) Sample Collection (Greatest Source of Error) Extraction and Analysis Interpretation Interpretation (based on correlation data) Recommendation Recommendation (based on calibration data)

Objectives Determine nutrient and pH levels of a specific land area

land area Determine variability in nutrient level and pH levels

within a field levels within a field Establish the probability of obtaining a crop response to

added nutrients and lime response to added nutrientsadded nutrients and lime response to added nutrientsand lime

Recommend fertilizer and lime rates which areeconomical and environmentally safe are economical andenvironmentally safe

Measure the effectiveness of fertilizer managementprograms management programs

Pengambilan sampel tanahDua macam pengambilan sampel tanah:1. pengambilan sampel pada tiap horizon dalam profil tanah

(umumnya untuk survei tanah dan klasifikasi tanah), tetapikurang sesuai untuk evaluasi kesuburan tanah untukrekomendasi pemupukan, kenapa?, karena hanyarekomendasi pemupukan, kenapa?, karena hanyamenunjukkan tanah pada titik tertentu

Pengambilan sampel tanah2. pengambilan sampel tanah pada plot untuk karakterisasi

kesuburan rata-rata dari wilayah tersebut dengan tujuanuntuk rekomendasi pemupukan. wilayah yang diambil sampelnya dikelompokkan, paling tidak

dalam 10 - 20 tempat pengambilan sampel, biasanya cukuppada kedalaman 15-20 cm. Masing-masing sampel kemudiandikompositkan dan diambil subsampel sekitar 500 g untukdikompositkan dan diambil subsampel sekitar 500 g untukanalisis di laboratorium.

Hasil yang diperoleh dari pendekatan tersebut secara hati-hatidigunakan untuk menduga kondisi tanah, berkaitan denganiklim, pertumbuhan tanaman dan tingkat produksi yangdiharapkan

Plant Analysis A diagnostic tool to be used in combination with soil

analysis. Based on the concept that the amount of specific nutrient

element in the plant is directly related to thequantitv ofthat element inthe soil.that element inthe soil.

Usually done only when a problem arises Interpreting the results of plant tissue analysis is difficult

Plant sampling1. Usually done prior to or at the beginning of a reproductive

phase.2. Sample the correct plant part - on instruction sheet - usually the

most recently matured leaves.Do not sample dead plants etc. - see instruction sheet3. Do not sample dead plants etc. - see instruction sheet

4. Place sample in paper mailing envelope. (Not in plastic) so itcan begin to air dry. Let succulent plants (cabbage, potatoes) airdry a day before mailing

Plant sampling5. Take samples from an area with normal plant for

comparison.6. There is year to year and soil to soil variation in

analysis. crop varieties also differ7. Fill out the questionnaire accurately.7. Fill out the questionnaire accurately.8. Take a soil sample at the same location and the same

time and send along with plant sample

Akhir materi 6Minggu depan; Perawatan

KesubutanTanah

evaluasi kesub tanah.pdf

Documents