Pre-Irrigation Soil Survey

Abstract

IN the first phase of Damodar Valley Corporation's work is included irrigation over one million acres in the Lower Valley. In addition in the Upper Valley, the areas to be irrigated by headwater dams that are included in the first five-year programme approximate 100,000 acres. Irrigation is the artificial application of water to land where the rainfall is either not sufficient or is erratic enough so that it does not come in time to meet the water require-ments of crops for optimum yield. Different soils have different water relations according to their texture, depth and other physio-chemical properties. Lands which are to be selected for irrigation require a careful ex-amination as to the character of the soil, its depth, its behaviour towards irrigation, slope and evenness of the surface, presence and depth of injurious salts in the profile, facilities for drainage, etc. For this purpose, pre-irrigation soil survey which groups the soils into different categories on the basis of their physical characteristics, salt distri-bution and permeability, etc., is absolutely essential. The need for such a survey is more obvious as the water required for irrigation is costly and should be utilized to the maxi-mum extent and with the minimum of wastage.