Saline and alkaline soils and their grading
Amending saline and alkaline soils procedure
The main problem in amending alkaline soils is their degraded structure and toxicity resulting from the sodium presence. First step in amending such soils is to apply large amounts of calcium in form of small calcium sulfate particles. (several tons per hectare) to displace sodium by calcium. The smaller particles of calcium sulfate are. And the more uniformly they’re incorporated into the soil, the better and more rapidly sodium will be replaced by calcium. After soil’s amended by calcium sulfate application and its permeability increases, it’ll be leached as saline soil (it’ll be washed).
Soils are divided into the following grades based on their agricultural suitability:
- Grade zero: These soils are free of salt and do not limit plant growth
- Grade 1: Soil salt content affects sensitive plants but does not hamper growth of halophytic plants
- Grade 2: Soil salt content decreases normal growth of all plant species
- Grade 3: Soil salt content is high and only a few plant species (salt resistant plants ) are resistant to the salt content of such soils
Note: Soil electrical conductivity (EC), which is a function of soil salt content, is criterion used to determine soil grade. The Soil pH must also be measured when studying the saline and the alkaline soils. In the most soils with the pH values higher than grade 9 there is a large amount of exchangeable sodium.