Problematic soil
Expected question in AFO-2019
While the reclamation reclamation of Salt Salt affected soil, tillag tillage e operation should be? •
Same as before
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Increased
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Decreased
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Increase with increase in pH
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None of these
Excessive amount of adsorbed sodium can be found in? •
Acidic soil
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Alkaline soil
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Saline Soil
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Saline alkaline soil
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None of these
Alkaline soil can be found in the area?
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Arid region
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Semi arid region
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High groundwater table
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Both A and B
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All of these
Which Crop Crop is suitable while the reclamation reclamation of salt affected soil? •
Cotton
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Sugarbeet
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Wheat
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Rice
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None of these
Answers will be discussed after this class
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Recognising Recognising the importance of soil health health in all dimensions,
2015 has been declared as the International Year of Soils by the 68th UN General Assembly. •
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It is estimated estimated that out of the 3,287,2 3,287,263 63 m ha of the total geographical area in India, 6744968 ha are degraded, producing less than 20% of its potential yield. Soil consists of a solid phase (minerals and organic matter) as well as a porous phase that holds gases and water. Accordingly, soils are often treated as a three-state system
soils are often treated as a three-state t hree-state system
Establishment of CSSRI, Karnal
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Central Soil Salinity Research R esearch Institute (CSSRI) is a premier research research institute dedicated to research on salinity/ alkalinity management and use of poor quality irrigation waters.
it was decided to establish the Central Soil Salinity Research Institute under Fourth Plan period. The Institute Institute started started functionin functioningg at Hisar (Haryana) (Haryana) on 1st March, March, 1969. Later on, it was decided to shift this Institute to Karnal during October, 1969.
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In February 1970, the Central Rice Research Station, Canning Town, West Bengal was transferred to CSSRI, C SSRI, Karnal to t o conduc c onductt research research on problems of coastal salinity s alinity..
Types of problem soils
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Physical problem soils
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Chemical Problem soils
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Biological Problem soils
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Nutritional problem soils as a result of above constraints
Soils with Physical problems
Slow Slo w permeable soils/Impermeable soils and their management: •
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Slow permeable soil is mainly due to very high clay content, infiltration rate < 6cm/day, so more runoff which eventually leads to soil erosion and nutrient removal. Since the capillary porosity is high it leads to impeded drainage, poor aeration and reduced conditions.
Remedial measures •
Incorporation of organics
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Formation of ridges and furrows furrows
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Formation of broad beds
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providing open/ subsurface drainage
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Huge quantity of sand /red soil application to change the texture Contour /compartmental bunding to increase the infiltration
Soil surface crusting
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Surface crusting is due to the presence of colloidal oxides oxides of iron iron and aluminium aluminium in soils which which binds binds the soil particles under wet regimes. On drying dryin g it forms a hard mass on the surface. surface . It is predomina predominant nt in Alfisols Alfisols but also occur in other soils soils too.
Remedial measures •
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When the soil is at optimum moisture regime, regime, ploughing is to be done. Lime or gypsum @ 2 t ha-1 may be uniformly spread and another ploughing given for blending of amendment with the surface soil.
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Use of Farm yard manure or compost
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More number of seeds/hill may be adopted for small seeded crops.
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Sprinkling water at periodical intervals may be done wherever possible.
Highly permeable soils
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Sandy soils containing more than 70 per cent sand fractions occur in coastal areas, river delta and in the desert belts.
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The soils should be ploughed uniformly. Twenty four hours after a good rainfall or irrigation, the soil should be rolled 10 times with 400 kg stone roller of 1 m long or an empty tar drum filled with 400 kg sand at optimum moisture (13 %).
Application of clay clay soil up to a level level 100 t ha-1 based on the severity of the problem and availability availability of clay materials. Crop rotation with green manure crops like li ke Sunhemp, sesbania, sesbani a, daincha, daincha, kolinchi kolinchi etc
Chemical Problematic soils
Salt Sa lt - af affe fect cted ed soi soils ls
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The salt-affected soils occur in the arid and semiarid regions where evapo-transpiration greatly exceeds precipitation. The accumulated ions causing salinity or alkalinity include sodium, potassium, magnesium, calcium, chlorides, carbonates and bicarbonates. The salt affected soils can be primarily classified as saline soil and sodic soil.
Why Wh y do some plants prefer prefer alkaline soil
Extent and distribution of salt affected soils in India
Sr. No.
S t at e
Saline soils (ha)
Alkali soils (ha)
Coastal saline soil (ha)
Total (ha)
1 2 3 4
Andhra Pradesh A & N islands Bihar Gujarat
0 0 47301 1218255
196609 0 105852 541430
77598 77000 0 462315
274207 77000 153153 2222000
5 6 7 8 9 10 11 12 13 14 15
Haryana J & K* Karnataka Kerala Maharashtra Madhya Pradesh Orissa Punjab Rajasthan Tamil Nadu Uttar Pradesh
49157 0 1307 0 177093 0 0 0 195571 0 21989
183399 17500 148136 0 422670 139720 0 151717 179371 354784 1346971
0 0 586 20000 6996 0 147138 0 0 13231 0
232556 17500 150029 20000 606759 139720 147138 151717 374942 368015 1368960
16
West Bengal Total
0 1710673
0 3788159
441272 1246136
441272 6744968
Data given by CSSRI, Karnal
Distribution of salt affected soils in Agr Agrooclimatic Zones
Zone No.
Name of the zone
Salt affected area
Ha
%
3
Lower Gangetic Plains Region
628400
9.3
4
Middle Gangetic Plains Region
476018
7.0
5
Upper Gangetic Plains Region
848340
12.6
6
Trans-Gangetic Plains Region
765470
11.3
7
Eastern Plateau & Hills Region
17280
0.5
8
Central Plateau and Hills Region
719370
10.7
Zone No.
Name of the zone
Salt affected area
Ha
%
9
Western Plateau & Hills Region
441550
6.5
10
Southern Plateau & Hills Region
535090
7.9
11
East Coast Plains and Hills Region
925310
13.7
12
West Coast Plains and Hills Region
58080
0.9
13
Gujarat Plain and Hills Region
953910
14.2
14
Western Dry Region
282010
4.2
15
Island Region
77000
1.2
Total
6727468
100.0
Saline soil/White alkali-
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Formation : Common in arid and semi – arid regions having
annual rainfall less than 55cm. •
Lots of salts are deposited on soil surface in saline soils and saline soil layer shines white in dry season.
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Formerly these soils were called white alkali soils because of surface crust of white salts.
Formation
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The process by which the saline soil formed is called Salinization. Saline soils occur mostly in arid or semi arid regions.
Characteristics •
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Toxic concentration of soluble salts in the root zone. Soluble salts are Cl- and SO42- of ions of sodium and calcium in root zone For these soils with electrical conductivity of more than 4 ds/ m at 250c. The exchangeable sodium percentage (ESP) is less than 15 % and pH less than 8.5
Reclamation of saline soil
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Flooding or leaching of soluble salts by good irrigation
water. •
Removal of excess salts to a desired level level in the root zone.
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Use of FYM for saline soil.
Crop choice / Crop management:
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Crops are to be chosen based on the soil salinity level. The relative salt tolerance of different crops is given in the table:
Plant species
Threshold salinity (dS (d S mm-1 1)
Field crops Cotton
7.7
Sugarbeet
7.0
Sorghum
6.8
Wheat
6.0
Soybean
5.0
Groundnut
3.2
Rice
3.0
Maize
1.7
Sugarcane
1.7
From this data question was asked in AFO-2018, AICL-2018, NABARD-
Plant species
Threshold salinity (dS mm-1 )
Vegetables Tomato
2.5
Cabbage
1.8
Potato
1.7
Onion
1.2
Carrot
1.0 Fruits
Citrus
1.7
Alkaline soil /Sodic soil •
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Formation : Salt accumulation is the first stage in the sequence of processes and it is common to the family of salt affected soil.
Dominant in mean annual rainfall 55-90 cm and relatively relatively low lying areas with insufficient drainage. Alkali or sodic soil is defined as a soil having a conductivity of the saturation saturation extract extract less than than 4 dS m-1 and an exchangea exchangeable ble sodium percentage greater than 15.
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The pH is usually between 8.5 – 10.0. Most alkali soils, particularly in the arid and semi-arid regions, contain CaCO3 in the profile in some form and constant hydrolysis hydrolysis of CaCO3 sustains sustains the release release of OHions in soil solution. The OHions OHions so released released result result in the maintenance maintenance of higher higher pH in calcareous alkali soils than that in non – calcareous alkali soils.
Characteristics:
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Developed Dev eloped due to excess NaCO3 and NaHCO3 ions in soil.
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Black colouerd, found in semi arid and sub humid area .
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For these soils with electrical conductivity of less than 4 dS/ m at 250c. The exchangeable sodium percentage (ESP) is more than 15 % and pH more than 8.5
Formation Form ation of saline and alkali soils ? •
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1. Weathering of rocks and minerals:-The soluble salts released during weathering leach down with rain water , but again move upward due to high temperature and accumulate as white crust forming a saline soil. 2. Hydrolysis of sodium saturated exchange complex in the formation of an alkali soil:- Sodium carbonate undergoes hydroly hydrolysis sis to form form sodium hydroxide,which hydroxide,which dissociates to increase increase concentrationof hydroxyl hydroxyl ions in soil soil solution.
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Formation of OH results in an increase in pH
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3.Salty underground water :-If the ground water is salty move upward with water and get deposited when water evaporates 4.Arid and semi arid climate :-The low rainfall is not sufficient to leach down the soluble weathered products products and hence the
salts accumulate in the soil.
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5. Use of basic fertilizer:-Basic fertilizer :-Basic fertilizers like NaNO3 and basic slag may develop soil alkalinity.
Reclamation of Alkaline Alkaline soil
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Gypsum used for reclamation of sodic or alkali soil .
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Iron pyrite can be used for amendments of alkali soil.
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Green manuring should be adopted.
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Cultivation of salt tolerant crop.
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In case of saline soils Gypsum should’t be recommended because sulphat sulphatee also increases increases salt concentra concentration tion .
Relative tolerance of crops to sodicity ESP (range*)
Crop
2-10
Deciduous fruits, nuts, citrus, avocado
10-15
Safflower, black gram, peas, lentil, pigeon pea
16-20
Chickpea, soybean
20-25
Clover, groundnut, cowpea, pearl millet
25-30
Linseed, garlic, cluster bean
30-50
Oats, mustard, cotton, wheat, tomatoes
50-60
Beets, barley, sesbania
60-70
Rice
Relative tolerance of fruit trees to sodicity Tolerance to sodicity
ESP
Trees
High
40-50
Ber, tamarind, sapota, wood apple, date palm
Medium
30-40
Pomegranate
Low
20-30
Guava, lemon, grape
Sensitive
20
Mango, jack fruit, banana
Saline-alkali/ sodic soils •
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Saline-alkali / sodic soil is defined as a soil having a conductivity of the saturation saturation extract extract greater greater than 4 dS m-1 and an exchangeable exchangeable sodium percentage greater than 15. The pH is variable and usually above 8.5 depending on the relative amounts of exchangeable exchan geable sodium and soluble salts. When soils dominated by exchangeable exchan geable sodium, the pH will be more than 8.5 and when soils dominated by soluble salts, the pH will be less than 8.5.
Formation
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These soils form as a result of the combined processes of salinisation salinisation and alkalization. alkalization. If the excess soluble salts of these soils s oils are leached downward, the properties of these soils s oils may change markedly and become similar to those of sodic soil.
Parameters of different problematic soil
Soil Saline Alkaline SalineAlkaline
pH
EC (dS /m)
ESP
< 8.5
>4
< 15
> 8.5
<4
> 15
> 8.5
>4
> 15
Keys to the degree of salinity / sodicity Degrees
Salinity
Sodicity
EC (milimhos per centimeter)
pHs
ESP
Slight
4.0-8.0
8.5-9.0
< 15
Moderate
8.1-30.0
9.1-9.8
15-40
Strong
>30
> 9.8
>40
Standards given by CSSRI, Karnal
Calcareous soil
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Calcareous Calcareous soil that contains enough free calcium carbonate (CaCO3). The pH of calcareous soil is > 8.5 and it is also regarded as an alkaline (Basic) soil.
Salt tolerant crops
High salt tolerant crops
Medium salt tolerant crops
Low salt tolerant crops
Barley, Dhencha, Sugar Sug arbee beet, t, Turnip, urnip, Radish Rad ish,, Spinach Spinach,, Doob grass grass
Rye, Rye , Wheat, Whe at, Must M ustard, ard, Oat, Rice, Jowar, Bajra, Maiz Ma izee, Tomat om ato, o, Cauliflower, Cabbage, Tomato, Onion, Lucerne, Barseem
Sembea Sem bean, n, Mung, Mun g, Urd, Gram, Pea, Ladt finger, finger, Bottle gourd, Apple, Apple , Orange, Orange , Lime, Lime , Papaya.
Question to discuss
While the reclamation reclamation of Salt Salt affected soil, tillag tillage e operation should be? •
Same as before
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Increased
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Decreased
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Increase with increase in pH
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None of these
Excessive amount of adsorbed sodium can be found in?
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Acidic soil
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Alkaline soil
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Saline Soil
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Saline alkaline soil
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None of these
Alkaline soil can be found in the area?
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Arid region
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Semi arid region
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High groundwater table
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Both A and B
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All of these
Which Crop Crop is suitable while the reclamation reclamation of salt affected soil? •
Cotton
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Sugarbeet
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Wheat
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Rice
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None of these
Acidic soil
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Highest acidic soil found in W West est Bengal. (In Area)
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Acidity due to absorption of Al+3, Fe+2, Mn on soil colloids.
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In acid soil regions (ASR) precipitation exceeds the evapotranspiration and hence leaching is predominant causing loss of bases from the soil.
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95% of soils of Assam and 30% of geographical area of Jammu
and Kashmir are acidic. •
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In West Bengal, 2.2 M ha, in Himachal Pradesh, 0.33 M ha, in Bihar, Bihar, 2 Mha and all hill soils of erstwhile Uttar Pradesh come under acid soils. About 80% of soils in Orissa, 88% in Kerala, 45% in Karnataka and 20% in in Maharastra Maharastra ar are e acidic.
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Acid soils occupy approximately approximately 60% of the earth land area and are arise under humid climate conditions from carbonaceous less soil forming rocks in all thermal belts of the earth.
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World wide – 800 M ha
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Indi Indiaa - 100 100 M ha
Acid soil manag management ement •
Use of Agriculture Agriculture liming material such as oxide, hydroxide, carbonates of Ca and Mg. pH range
Nature of acidity
3-4
Very strong
4-5
Strong
5-6
Moderate
6-7
Slight
Production Produ ction constraints
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Increased solubility and toxicity of Al, Mn and Fe
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Deficiency of Ca and Mg.
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Reduced availability of P and Mo.
Relative tolerance of Relative crops cr ops to soil soil acidity
Crops
Optimum pH range
Cereals Maize, sorghum, wheat, barley
6.0-7.5
Millets
5.0-6.5
Rice
4.0-6.0
Oats
5.0-7.7
Crops
Optimum pH range
Legumes Field beans, soybean, pea, lentil etc
5.5-7.0
Groundnut
5.3-6.6 Others
Sugarcane
6.0-7.5
Cotton
5.0-6.5
Potato
5.0-5.5
Tea
4.0-6.0
Low acidity tolerant crop
Medium acidity tolerant crop
High acidity tolerant crop
Cauliflower, Sugar beet, Berseem, Lucerne
Wheat, Barley, Oat, Maize, Bajra, Jowar, Potato
Rye, Grasses
Acid Sulphate soils •
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Acid sulphate are drained coastal wetland soils that have become acid (pH). Undrained soils containing pyrites pyrites need not be acid and they are called potential acid sulphate soils. Soil with sufficient sufficient sulphides (FeS2 and others) others) to become strongly strongly acidic when drained are termed acid sulphate soils or as the Dutch refer to those soils soi ls cat clays. n India, Indi a, acid sulphate s ulphate soil is, i s, mostly found foun d in Kerala, Orissa, Andhra Pradesh, Prad esh, Tamil Nadu and West West Bengal. Ben gal.
Some Important facts
Holard,, chresard Holard chresard,, and echard
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Hollard means total amount of water available in soil.
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Chresard means amount of water available to plants.
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Echard means amount of water not available to plants.
SIZE OF THE PAR ARTICLES TICLES (IN SOIL TEXTURE TEXTURE)) •
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Particle size is determined by the diameter of individual soil fragments. According to the International system of soil classification ,size of different different particle are as follows:
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Clay –
less than 0.002 mm
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Slits – 0.002mm to 0.02mm
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Sand – 0.02mm to 2.0mm
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Gravel
- larger than 2.0 mm
TEXTURAL GROUPS Textural groups
Relative proportion of different sized Mineral particle
Sandy soil
85% sand + 15%clay or slit or both
Loamy sand
70% sand + 30% clay or slit or both
Loam soil
50% sand +50% clay or slit or both
slit
90% slit + 10% sand
SERIAL NUMBER
SOIL CLASSES OR TEXTURAL NAMES
RANGE IN I N RELATIVE RELATIVE PERCENT P ERCENTAGE AGE OF SOIL SEPARATES
SAND
SILT
CLAY
1 2 3 4 5 6 7 8 9 10 11
Sandy soil Loamy sand Sandy loam Loam Silt loam Silt Sandy clay loam Clay loam Silty clay loam Sandy clay Silt clay
85-100 70-90 43-80 23-52 0-50 0-20 45-80 20-45 0-20 45-65 0-20
0-15 0-30 0-50 28-50 50-88 40-100 0-28 15-53 40-73 0-20 40-60
0-10 0-15 0-20 7-27 0-27 0-12 20-35 27-40 27-40 35-45 40-60
12
clay
0-45
0-40
40-100
Thank You
