Use and Management of Poor Quality Waters for the Rice-Wheat Based Production System

Abstract

Summary India's major improvements in food production have been made possible via a shift towards rice-wheat systems as a consequence of enhanced utilization of ground waters. Rice-wheat rotation covering 10.5 million ha contribute about 75 percent of total food production. But it is being observed now that yield increases in rice and wheat has slowed down and there is rather a decline in factor productivity. One of the major reasons for this decline is indiscriminate use of alkali waters constituting about 25-42 percent of ground waters surveyed especially in the northwestern states of the Indo-Gangetic Plains (IGP). Because of high water requirements of the system, sodication rates of soil being irrigated and their steady state pH and sodicity values are much more (about 1.8 times) than that of the low water requiring rotations like millet/maize-wheat. So there has been a dilemma on whether or not rice-wheat system should be advocated with alkali irrigation waters. Consistent research efforts have lead to the guidelines for irrigation with such waters with respect to their amendment needs (gypsum requirements, frequency and mode of application), conjunctive use with canal waters and use of organic materials and chemical fertilizers, etc. These results do show that subject to the following of specific soil-water-crop management systems, it is possible to control the build up of sodicity in soils and sustain crop yields. Options available in terms of management practices and some of the researchable issue are discussed in this paper.