Posted On:July 31, 2024

Soil is the backbone of farming. But when too much salt builds up in the soil, crops cannot grow properly. This problem is called soil salinity. It is common in dry and irrigated areas of India and is a major reason for low crop yield.

Understanding what is soil salinity and learning proper soil salinity management can help farmers protect their land and improve production.

What is Soil Salinity?

Soil salinity means there is too much salt in the soil. When salt levels become high, plants cannot take in water and nutrients properly, so their growth becomes weak and crop yield decreases.

Farmers may see white salt layers on the soil surface. This problem happens due to natural reasons or human activities like over-irrigation and too much fertilizer use, especially in dry areas where water evaporates quickly, leading to poor soil health.

Normal soil EC: Below 2 dS/m
Saline soil EC: Above 4 dS/m

Types of Soil Salinity

There are 3 different types of soil salinity: primary, secondary, and dryland salinity, and how each type affects soil health.

1. Primary Salinity (Natural)

Happens naturally, not because of farmers
Rocks in the soil slowly release salts
Wind or seawater can also bring salts
Common in dry areas with less rainfall
Water dries fast, but salts stay in the soil

2. Secondary Salinity (Caused by People)

Happens due to farming activities
Too much irrigation adds extra water and salts
Poor drainage does not allow salts wash away
Too many fertilizers increase the salt level
Cutting trees makes the underground water rise
Salty water comes up and stays in the topsoil

3. Dryland Salinity

A type of secondary salinity
Happens after removing deep-rooted trees
Crops have shallow roots and can’t absorb deep water
Underground water rises to the surface
This water carries salts
Salts collect near plant roots and damage crops

Causes of Soil Salinity in India

Soil salinity happens due to both natural and human reasons:

Too Much Irrigation & Waterlogging: When farmers use too much water, the underground water level rises. This water brings salts up to the root area. When water dries, salts stay in the soil.
High Heat in Dry Areas: In hot places with less rain, water dries very fast. But salts do not dry; they stay in the top soil and build up.
Sea Water Mixing (Coastal Areas): In places near the sea, salty seawater can mix with fresh water. This makes the soil more salty.
Poor Drainage: If extra water cannot flow out of the field, salts cannot be washed away. So, they collect in the soil.
Using Salty Groundwater: When farmers use salty or brackish water for irrigation, salts directly enter the soil.
Natural Soil & Rocks: Some soils and rocks naturally contain salts. Over time, these salts come into the soil.
Farming Practices: Too much chemical fertilizer increases salt levels. Also, cutting deep-rooted plants and growing shallow-root crops makes underground water rise, bringing salts to the surface.

Soil Salinity Management Strategies

Practical methods like proper drainage, leaching, soil amendments, and salt-tolerant crops can control soil salinity and improve crop productivity.

1. Leaching (Washing salts down)

Farmers can use extra fresh water to wash salts from the topsoil down below the root area.
This helps roots grow in soil with less salt.
But the water must be of good quality (not salty).
Leaching works best after harvest or before sowing.

2. Drainage (Removing salty water)

When salts are washed down, that salty water must move out of the field.
For this, farmers need proper drainage systems like underground pipes, open channels, or field drains.
Without drainage, salts will come back to the surface again.

3. Growing Salt-Tolerant Crops

Some crops can survive better in salty soils.
Farmers can grow crops like barley, mustard, cotton, sugar beet, and some fodder grasses.
These crops give better yields in saline fields compared to sensitive crops like beans.

4. Using Salt-Tolerant Rootstocks

In fruit farming (like citrus or mango), special roots that tolerate salt can be used.
These roots help plants survive even if the soil has some salt.

5. Mulching

Covering soil with straw, dry leaves, or plastic mulch reduces water evaporation.
When less water evaporates, fewer salts rise to the soil surface.
This keeps salts deeper in the soil and protects roots.

6. Adding Manure, Compost, and Biochar

Organic materials like bio-stimulants make soil soft and improve its structure.
They help soil hold water better and support good microbes.
This improves root growth and reduces the harmful effects of salts.

7. Gypsum Use

Gypsum (calcium sulfate) is very useful in salty and sodic soils.
It replaces harmful sodium with calcium.
This improves soil structure, allows water to pass easily, and helps wash salts away.

8. Do Not Over-Irrigate

Too much water raises the underground water level and brings salts up.
Farmers should give only the required water based on the crop's needs.

9. Proper Water Management

Sometimes a small extra amount of water is needed to wash salts down.
This is called the leaching requirement. But it must be planned properly.

10. Avoid Deep Tillage

Deep ploughing can bring hidden salts from lower soil to the surface.
Light and controlled tillage is better.

11. Removing Salt Crusts

If white salt layers are seen on the soil surface, farmers can scrape off the top salty layer and remove it from the field.
This gives quick relief, but it is only a temporary solution.

Conclusion

Soil salinity is a serious problem, but it can be controlled with proper care. By improving irrigation, drainage, crop choice, and soil management, farmers can restore soil health and increase crop yields. Good soil salinity management means better productivity, better income, and long-term soil protection.

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