Soils affected by soluble salts, principally sodium, magnesium, sulfate, chloride, and calcium, and subsequently potassium, nitrate, carbonate, bicarbonate, and boron, are referred to as saline and alkaline soil. They are sometimes referred to as Usara soils. Saline soils are mostly made up of soluble salts. Alkali soils have a lot of sodium accumulated on them. However, because of prior leaching, it may not necessarily contain an overabundance of soluble salt. Therefore, they are classified as saline-alkali or non-saline-alkali soils based on their salt concentration.

Alkaline Soils

Clay soils with a pH of more than 8.5 are classified as alkaline soils. The higher pH is caused by high quantities of salt, magnesium, and calcium. Furthermore, hard water can cause the pH of soils to rise to alkaline proportions. On the other hand, sodium carbonate is the dominant component in alkaline soil. Therefore, alkaline soils inflate when exposed to sodium carbonate.

Saline Soils 

When there is an overabundance of sodium ions in the clay and soil complex that still includes exchangeable calcium, the soil is referred to as saline soil, brown alkali soil, or white alkali soil. This soil continues to be flocculated or granulated. As a result, it has air and water permeability.

Agriculture on Saline and Alkaline Soils

Coconut trees may be found in abundance in coastal settings. In addition, as previously stated, farming salt-tolerant crops such as dhaincha, berseem, and other grain legume crops may aid in the reclamation of these soils. Moreover, some of the suitable agriculture on saline-alkaline soil is mentioned below:

  • Suitable Crops: Barley, Cotton, Sugar beet, Sugarcane, Rice, Mustard, Maize, Green Gram, Red Gram, Sunflower, Sesame, Linseed, Sorghum, Bajra, etc.
  • Suitable Vegetables: Tomato, Cauliflower, Cabbage, Cucumber, Bitter guard, Pumpkin, Spinach, etc.
  • Suitable Fruits: Guava, Beetroot, Asparagus, Coconut, Banana, Grape, Pomegranate, Date palm, etc.

Features of Saline and Alkaline Soils

  • The topsoil of Saline and Alkaline Soil is permeated (saturated or soaked with a material) with alkaline and saline efflorescences.
  • Weathering produces calcium salts, magnesium, sodium, and sulfurous acid from inert rock pieces.
  • In areas with a lower water table, salts permeate the subsurface, but in areas with high drainage, salts are washed away by running water.
  • Certain salts are delivered in suspension by rivers.
  • In places with a higher subsoil surface water, harmful salts are carried below by capillary forces during the summer months due to evaporation.
  • Water with a high salt content becomes stationary in places with inadequate drainage and accumulates all of the salt contents in the soil layer as it dissipates.

Alkaline and Saline Soil Areas in India

Saline and Alkaline Soil covers an area of 68,000 square kilometers. These soils are formed in canal rinsed lands and locations with a higher subsurface water table. This type of soil may be found in parts of Karnataka, Telangana, Andhra Pradesh, Uttar Pradesh, Bihar, Punjab, Haryana, Rajasthan, Punjab, and Maharashtra. However, the build-up of the salts leaves the soil unproductive and unsuited for cultivation. 

The sea tides transporting salt-laden sediments damage the lands near the Khambhat Gulf of Gujarat. As a result, vast portions of the Mahi, Tapi, Narmada, and Sabarmati rivers are unproductive. When severe storms, salty sea waves invade coastal locations, rendering the soil unsuitable for farming. This type of soil deterioration is prevalent in low-lying coastal Tamil Nadu and Andhra Pradesh.

Significant Similarities of These Soils

Some essential similarities among both the soils are mentioned below:

  • The pH of both the soil is greater than 7.
  • Both soils are unsuitable for plant development.
  • The accessibility of plant nutrients is poor in both soils.
  • Both soils are found in places with low rainfall.
  • These soils are formed as a result of mineral weathering.

Key Differences of These Soils

A few of the essential differences are as under:

  •  The main difference between saline and alkaline soil is that the pH of saline soils varies from 7 to 8.5, whereas, for alkaline soils, the pH is more than 8.5.
  • The organic matter concentration of salty soils is greater than that of alkaline soils.
  • Furthermore, saline or salty soil has high electrical conductivity, whereas alkaline soil has low conductivity. 
  • Saline soils contain a sodium exchangeable proportion below 15%, whereas alkaline soils comprise more than 15% sodium exchangeable percent. As a result, there is another difference between saline and alkaline soil.

Conclusion

So, it was all about alkaline and saline soils. Both are fundamental soils with fundamental features. Saline soils have an abundance of sulfate salts and neutral soluble chloride, while alkali or sodic soils have sodium carbonates. However, neither soil supports optimal plant development due to a lack of plant nutrients. To gain more insight check the questions below.