ABSTRACT
Worldwide, more than 800 million hectares of land are estimated to be salt-affected. Agricultural soils accumulate salts in the root zone by various processes, including weathering of minerals, salt added through rain, agronomic practices, groundwater intrusion, irrigation, and other waste materials. The constituent cations and anions in solutions of salt-affected soils affect both soil properties and crop productivity. The interactions between rootzone environments and plant response to increased osmotic pressure or specific ion concentrations are also influenced by the soil processes such as soil water dynamics, soil structural stability, and soil pH and pE. Soil structural stability affects plant performance and also the environment by way of soil erosion. There are 12 categories of salt-affected soils based on the sodium adsorption ratio and electrical conductivity of the soil saturation paste extracts, and pH of soil 1:5 extracts. The mechanisms by which plant growth is affected are specific to each category. Elements toxic to plant growth can occur naturally in these soils and also due to use of wastewater and waste materials such as biosolids, sewage sludge, and compost. The solubilities of these elements are influenced by several factors, but mainly by soil pH and pE. Management of salt- affected soils in relation to agricultural production and environmental protection can be achieved by three ways, viz. prevention of salt accumulation, removal of accumulated salts, and adaptation to saline environment by growing appropriate salt-tolerant crops. While minimizing salt load in the root zone, care should be taken to avoid leachates from the soil contaminating the deeper soils or the surroundings in the drainage disposal region.
