🧫 Genesis, Characteristics,

This lesson covers saline soil formation, constraints, and practical management strategies relevant for Indian field conditions.

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Learning Objectives

To study the genesis, characteristics and reclamation of saline soils

Saline soils are defined as soils having a conductivity of the saturation extract greater than 4

dS m [-1] and an exchangeable sodium percentage less than 15. The pH is usually less than 8.5.

Formerly these soils were called white alkali soils because of surface crust of white salts.

Relationship between ECSE and EC1:2.5

Formation

EC (dS m-1)	Col2
Saturation extract	1: 2.5
4-8	1-3
8-12	3-8
12-16	8-16

The process by which the saline soil formed is called salinisation. Saline soils occur mostly

in arid or semi arid regions. In arid regions saline soils occur not only because there is less rainfall

available to leach and transport the salts but also because of high evaporation rates, which tend

further to concentrate the salts in soils and in surface waters.

Major production constraints

Presence of salts leads to alteration of osmotic potential of the soil solution. Consequently

water intake by plants restricted and thereby nutrients uptake by plants are also reduced. In this soil

due to high salt levels microbial activity is reduced. Specific ion effects on plants are also seen due

to toxicity of ions like chloride, sulphate, etc.

Management of saline soils

The reclamation of saline soils involves basically the removal of salts from the saline soil

through the processes of leaching with water and drainage. Provision of lateral and main drainage

channels of 60 cm deep and 45 cm wide and leaching of salts could reclaim the soils. Therefore,

provision of adequate drainage system is a pre-requisite for any reclamation process. Sub-surface

drainage is an effective tool for lowering the water table, removal of excess salts and prevention of

secondary salinisation.

Irrigation management

Efficient water management leads to increased crop yield under saline soil condition.

Proportional mixing of good quality (if available) water with saline water and then using for irrigation

reduces the effect of salinity. Alternate furrow irrigation favours growth of plant than flooding. Drip,

sprinkler and pitcher irrigation have been found to be more efficient than the conventional flood

irrigation method since relatively lesser amount of water is used under these improved methods.

Fertilizer management

Addition of extra dose of nitrogen to the tune of 20-25% of recommended level will

compensate the low availability of N in these soils. Addition of organic manures like, FYM, compost,

etc helps in reducing the ill effect of salinity due to release of organic acids produced during

decomposition. Green manuring (Sunhemp, Daincha, Kolingi) and or green leaf manuring also

counteracts the effects of salinity. Application of farm yard manure at 5 t ha [-1] at 10-15 days before

transplanting in the case of paddy crop and before sowing in the case of garden land crops can

alleviate the problems of salinity.

Crop choice / Crop management

Crops are to be chosen based on the soil salinity level. The relative salt tolerance of different

crops is as follows:

Relative tolerance of crops to salinity

Plant species	Threshold salinity (dS m-1)
Field crops	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
Vegetables	Vegetables
Tomato	2.5
Cabbage	1.8
Potato	1.7
Onion	1.2
Carrot	1.0
Fruits	Fruits
Citrus	1.7

Soil / cultural management

Planting the seed in the centre of the raised bed / ridge may affect the germination as it is the

spot of greatest salt accumulation. A better salinity control can be achieved by using sloping beds

with seeds planted on the sloping side just above the water line. Alternate furrow irrigation is

advantageous as the salts can be displaced beyond the single seed row. Application of straw and

polythene mulch had been found to curtail the evaporation from soil surface resulting in the reduced

salt concentration in the root zone profile within 30 days.

Management of saline soils becomes essential and unavoidable particularly in areas where

both soil as well as irrigation water is saline in nature.

Occurrence in India:

Extent and distribution of salt affected soils in India

Sr. No.	State	Saline soils (ha)	Alkali soils (ha)	Coastal saline soil (ha)	Total (ha)
1	Andhra Pradesh	0	196609	77598	274207
2	A & N islands	0	0	77000	77000
3	Bihar	47301	105852	0	153153
4	Gujarat	1218255	541430	462315	2222000
5	Haryana	49157	183399	0	232556
6	J & K	0	17500	0	17500
7	Karnataka	1307	148136	586	150029
8	Kerala	0	0	20000	20000
9	Maharashtra	177093	422670	6996	606759
10	Madhya Pradesh	0	139720	0	139720
11	Orissa	0	0	147138	147138
12	Punjab	0	151717	0	151717
13	Rajasthan	195571	179371	0	374942
14	Tamil Nadu	0	354784	13231	368015
15	Uttar Pradesh	21989	1346971	0	1368960
16	West Bengal	0	0	441272	441272
	Total	1710673	3788159	1246136	6744968

Source : www.cssri.org

Questions to Ponder

1)What is the relationship between salts and electrical conductivity?

2)What is the fate of leached ouyt salt during saline soil reclamation?

3)What is the nutrient management in saline soil?

4)Where is saline soil predominant in India?Why? ?

5)What are halophytes?

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Summary Cheat Sheet

Key Recall Points

• Genesis, Characteristics, is exam-relevant for SSAC122 and objective questions in soil science.
• Use soil-test based interpretation with focus on pH, CEC, and nutrient availability.
• Apply the 4R principle: right source, right rate, right time, and right method.

Exam Traps

• Do not mix up soil fertility concepts with fertilizer quantity alone.
• Numerical and term-based questions often test definitions, units, and threshold values.
• In problem-solving, interpretation must follow soil reaction, crop stage, and management context.

References

3 sources • [1] [2] [3]

[1]

ICAR e-Course: Soil Chemistry, Soil Fertility and Nutrient Management

Official

[2]

Brady and Weil, The Nature and Properties of Soils

Book

[3]

Indian Council of Agricultural Research

Official