Water Quality for Irrigated Agriculture

Abstract

Irrigation is generally practiced in the arid regions of the world, where evapotran-spiration is greater than the precipitation. The waters of these areas have a greater tendency to be of poor quality than those in the humid regions. The earth crust in its weathering, disintegration and decomposition in the process of soil formation liberates many soluble salts. This process is greatly enhanced by the high concentration of carbon dioxide, a weak acid, in the soil atmosphere and soil solution along with the humic acids from decomposition of organic matter. Where rainfall is sufficiently high to leach the soil with good drainage, the salts are carried away by the rivers, or by seepage to the ocean, but in the arid lands where the soils are not highly leached and surface drainage is poor the salts have a tendency to accumulate.