Soil Testing_Naregehehehehehheheender.ppt

Environment conservation

1. Soil Testing for Balanced and Judicious Use of
Nutrients for Sustaining Soil Productivity
Dr. Narender
Assistant Scientist

2. INTRODUCTION
SOIL TESTING
What is soil testing?
Soil testing is a tool to asses the available nutrient status of soil. It is
rapid soil chemical analysisto assess:
•Capacity of soil to supply nutrients (available N, P and K) to growing
plant.
•Interpretation of test results to make the fertilizer recommendation
based on crop response.
•The degree of acidity or alkalinity in the soil.
•The amount of soluble salts (salinity)/ and carbonate (alkalinity).
•Method of reclaiming the salt affected soil.
•Tell the suitability of soil for a particular crop/ fruit.

3. Objective of soil testing
Evaluation of nutrient availability for fertilizer recommendation
Soil fertility evaluation for mapping
Assessment of soil degradation problems
Study of crop response
Safeguard of soil quality

4. Components of soil testing
•Sampling & processing-most crucial
•Standard methods of analysis
•Scientific interpretation of test data
•Good knowledge of soil and crops
•Formulation of sound recommendation
•Follow-up of recommendations
•Feed back from farmers

5. What is soil?
•Upper most layer of earth
•Three dimensional entity
•Surface (about 6 inches) rich in nutrients and
organic matter
•Sub-soil management for drainage
•Contribution from sub-soil

6. Soil fertility & productivity
Soilfertilityistheinherentcapacityofsoiltosupply
plantnutrientsinrightamountandrightproportion
Productivityofsoilisitscapacitytoproduce
biomassdependingonsoilfertilityandseveral
otherfactorslikesoiltexture,soilborndiseases,
waterlogging(drainage),soildepthanderodibility
etc.

7. Soil Fertility Scenario
Indian Soils are inherently low in organic carbon
(OC)and Nitrogen Supply.
A mismatch between nutrient demands of crops and
replenishment through fertilizers is very common.
This led to emergence of multinutrient deficiencies in
soils.
Widespread deficiency of six nutrients namely, NPK, S,
Zn, B exist in Indian soils.
Poor soil fertility is one of the major causes of low
fertilizer use efficiency and dwindling farm profits.
In order to attain and sustain high productivity levels,
judicious nutrient supply has to be essentially ensured
through balanced and integrated use of nutrients.
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8. Soil Fertility Evaluation
1.SoilTesting
2.Planttesting
1.Nutrientdeficiencysymptoms
2.In-fieldevaluationofnutrientstatusoftheplant:(Chlorophyll
meters&leafcolourcharts)
3.Plantanalysis:(Criticalnutrientconcentration&thediagnosis
andrecommendationintegratedsystem(DRIS)
Biologicaltest:(Fieldtests,Greenhousetests,laboratorytests,
microbiologicalmethods)
DRIS:Thissystemidentifiesseveralnutritionalfactors
simultaneouslywhichdetermineyieldlevelandqualityof
produce.
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9. Essential Nutrients for Plants
Major/macronutrients
•C, H, O (never deficient, all from water & air)
•N, P, K ( primary nutrients, mostly from soil)
•Ca, Mg, S ( secondary nutrients, mostly from soil)
Minor/micronutrients
•Fe, Mn, Zn, Cu, Cl, B, Mo, Ni

10. Soil test parameters
•Problem related parameters–Salinity, Acidity,
Alkalinity (Sodicity)
•Nutrient availability-Available N, P, K, S, Zn,
Fe, Cu, Mn, B
•Support tests–Calcium carbonate, texture
•Special tests-not always

11. Soil analysis for field crops
Collection of soil sample:
A fertilizer recommendation made after analysis totally depends upon
soil sampling; hence the collection of the representative soil sample is
most important step.
Do not sample from:
•Farm lane and field border
•Locations where farm waste have been burnt
•Old manure piles or old straw stack bottoms
•After fertilizer/ FYM application
•Wet field
•Under the tree
•From salt affected patch
•Near the channel
•Dead furrows or head lands

12. How to collect soil sample?
•Divide entire farm in parts on basis of texture, slope and
fertility status
•Take separate sample from every field
•Select 8-10 representative spots for sampling in a field
•Make cut of 6 inches of V-shape in a soil at each spot
•Cut a strip of 2-3 cm soil from top to bottom with khurpa
•Collect this soil sample in a tray
•Mix all samples thoroughly
•Take about 400 g representative sample
•Put the sample in well clean, dry cloth/ polythene
•Put a label containing address, khasra no., previous and crop
is to be sown, source of irrigation in each sample bag.

13. When to collect soil sample?
•Once every three year
•Before 10-15 days of crop sowing
•In dry field after crop harvest
•In standing crop, in between two rows
•Remove grass or kankar from soil surface

14. Soil sampling of salt affected Soils
•Saltaffectedsoilsshouldbesampleddepthwise
separatelyupto3feet(0-15,15-30,30-60and60-90
cms)layers.Ifthereisconcretionlayer,itsdepth
andthicknessshouldbenotedandaseparate
sampleshouldbecollected.
•Samplingtools:augerordigpitwithhelpofkassi

15. Soil sampling of salt affected Soils
How to collect soil sample?
•Digaverticalpitinsoilupto3feet(90cm)withkassi.
•Markedatdistanceof15,30,60and90cmdepth.
•Holdbucketat15cmmarkandcollectaremoveduniformsliceofsoil
fromsurfaceto15cmintobucket.
•Aftermixingthoroughly,takesample(400g)incleandryclothbag.
•Likewise,collectseparatesamplefromotherdepthsi.e.15-30;30-60
and60-90cm.
•Ifthereishard-pan(kankarlayer),takeseparatesampleofitafter
notingitsdepth&thickness.
•Inaddition,asampleofsurfacecrustshouldbecollectseparately.
•Eachsampleshouldbelabeledandpackedseparatelyindicatingthe
depthoflayer.

16. Soil reaction
Ratings
pH Category Remarks
< 6.0 Acidic, unsuitable for
some crops
No reclamation
required
6.0-7.5Normal to most crops-do-
7.6-9.0Progressive slightly
alkaline to alkanity,
less productive
May require
reclamation
> 9.0 Sodic/alkali, unfit for
most crops
Definitely
needs
reclamation

17. Soil salinity
EC (dS/m) Category Remarks
< 1.0Normal No reclamation
required
1.0-2.0Marginal salinity,
may be critical
for seed
germination
May require
reclamation (desirable
in light soils)
> 2.0Excessive salts,
injurious for
crops
Definitely needs
reclamation, specially
in heavy textured soils
Ratings

18. Soil Salinity
•Regions of saline soils
•Causes of salinity
•Effect on plants
•Reclamation by leaching
•Choice of crops
•Scrapping off salt layer
•Strategies for using saline waters

19. Information required with soil sample
•Nature of soil
•Cause and source of salinity, if known.
•Rainfall (seasonal and annual)
•Irrigation source
•Depth of water table and natural drainage condition
•Crop rotation followed

20. Ratings of fertility status
Rating
Org. C
(%)
Available nutrients (kg/ha)
N P K
Low < 0.5 < 280 < 11 < 120
Medium 0.50-0.75280–56011–25120–280
High > 0.75 > 560 > 25 > 280
(A) Macronutrients

21. Nutrient
element
Critical level of deficiency in soil
(mg/kg)
S 10
Fe 4.5
Mn 2.0
Zn 0.6
B 0.5
Cu 0.2
Mo 0.1
(B) Sulphur & Micronutrients

22. Micronutrient use as foliar spray
Element Solution
conc. (%)
Salt to be used
Fe 1.0 Ferrous sulphate
Mn 0.5 Manganese sulphate
Zn 0.5 Zinc sulphate
Cu 0.025 Copper sulphate
B 0.2-0.5 Solubor
Mo 0.1-0.3 Ammonium molybdate

23. Constraints in Soil Testing
•Improper sampling
•Lack of analytical facilities
•Lack of expertise
•Outdated recommendations
•Poor linkage with farmers
•No feedback from end users
•Lack of awareness among farmers
•Lack of accountability at the level of service
providers

24. Suggestions
•Upward revision of fertilizer doses
•Establishment of new laboratories
•Modernization of existing labs
•Soil health clinics
•Educating farmers and extension staff about
soil sampling
•Soil health cards
•Human resource management and
development
•Feedback mechanism
•Policy at national level

25. Soil test based fertilizer recommendation
1.General recommendation
2.Soil test category: Based on value (Very low, low,
medium, high, very high)
3.Critical limit of nutrient: Used for micronutrient
(Graphical & Statistical method, Cate & Nelson, 1965 &
1971)
1.Nutrient Index value (NIV): describe the fertility status
of the soils for the purpose of mapping
NIV = Nl*1+Nm*2+ Nh*3/Nt

26. SYMBOL OF TRUST