Reclamation and Management of Alkaline and Saline Soils

Establish Appropriate Drainage Systems: Where poor drainage is the cause of the salinity, it would be necessary to establish good drainage systems to carry away the excess salty water.

Such drainage systems that are in use include pumping,  tile drains, drainage ditches and canals depending on the topography and soil type.

Deep ploughing could be used to improve the soil permability and therefore increase downward movement of percolating salty water.

Leaching Excess Salt: Where the soil remains permeable with adequate internal and surface drainage present, excess salt of saline soils could be leached with heavy application of low salt irrigation water. Good-quality irrigation water must be used to leach excess salts out of the root zone.

In typical warm arid regions where many of the large irrigation schemes in the world are located, accumulation of salts can be very substantial.

Therefore irrigation schemes in such semi-arid regions must be well managed to remove excess salts regularly from the root zone of the crops. The salt contents of irrigation water should not exceed 0.025 – 2.25 mmhos/cm.

In areas of water scarcity over irrigation is avoided by giving attention to leaching requirement (LR) which is defined as the additional water needed for leaching, over that needed to wet the profile (Miller and Donahue, 1990).

LR = ECix



ECir is the electrical conductivity of the irrigation water, and ECdr  is the electrical conductivity of the soil saturation extract at which a 50 percent decrease in yield is obtained in uniformly saline soil.

Note that the determination of leaching requirement of a soil a times depends on the salt sensitivity of tolerance of the crop to be grown.

For example, wheat and sorghum have a LR or 0.08; while lettuce, a more sensitive plant, has 0.20 implying that more water must be added to leach more salt under lettuce.

Read Also: General Features of Saline and Alkaline Soils (Halomorphic Soils)

Application of Organic Mulch on Soil Surface

The idea here is to lower surface evaporation and thereby reduce salt movement to the soil surface in evaporative water.

In some place, cotton gin trash, chopped woody plants and crop residues have been found helpful in reducing soil salinity.

Replacement of Excess Exchangeable Sodium

In saline-sodic and sodic (alkaline) soils, leaching directly with water low in salt may lead to further increase in the percent sodium saturation thereby increasing the concentration of the hydroxyl ions (OH) in the soil solution.

In such situation, the toxic sodium carbonate and bicarbonate are first converted to sodium sulphate by treating the soil with heavy application of gypsum (CaSO4.2H20) or sulphur. The resulting sodium sulphate is then leached out of the root zone with irrigation water.

Use of sulphur also reduces the intense alkalinity insodic soils. During the process of sulphur oxidation to suphate there is production of hydrogen ion (H+) which leads to lowering the pH of the soil.

Water Control

Application of light irrigation but at frequent intervals would keep the soil moist, dilute salts and lessen the toxic and osmotic effects of salts in the soil.

Young plant seedlings are more sensitive to salts than mature plants. Therefore, light irrigation should be more frequent immediately after planting the crop.

Appropriate Planting Position of Crops

Most salts concentrations are usually in the ridge and heap tops; planting methods should therefore avoid the center of wide ridges and the tops of narrow ridges or moulds.

Choice of Crops

Crops such as cotton, sorghum and barley that are tolerant or resistant to salty environment could be cultivated to successfully manage saline and alkaline lands.

Other consideration may be the adaptation of the crop to the crop to the climate or soil properties and the economic value of the crop.

The revenue derived from a high price crop would more than compensate the cost of managing the soil during cropping. In alkaline soils, crops such as Atriplex sp that accumulate Na+ could be grown and then removed completely away from the irrigated area.

A Good Crop Rotation can be an insurance against alkali trouble by building up the soil structure (through root action of tolerant plants) and improving its stability. Crops such as sweet clover, grass, Lucerne leys, and melon have been found useful in this regards.

In conclusion, salt- affected soils may be saline, sodic or saline-sodic which must be specially treated and managed carefully to reduce salt problems to make the soils useful for crop production.

Read Also: The Physical Soil Factors Affecting Crop Production

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Benadine Nonye

An Agric. Consultant & a Writer (With over 12 years of professional experience in the agricultural industry) - National Diploma in Agricultural Technology - Bachelor's Degree in Agricultural Science - Master's Degree in Science Education... Visit My Websites On: - It's All About Agriculture, The Way Forward! - The Most Reliable Global Agricultural & Waste Management Forum! - The Most Reliable Agricultural Job Board! - Your Reliable E-Learning Agricultural Academy! - For Proper Waste Management and Recycling Practices. Join Me On: Twitter: @benadinenonye - Instagram: benadinenonye - LinkedIn: benadinenonye - YouTube: Agric4ProfitsTV - Pinterest: BenadineNonye4u - Facebook: BenadineNonye

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