AN OVERVIEW OF DRAINAGE AND SALINIZATION PROBLEMS OF IRRIGATED LANDS

The development of irrigated agriculture is essential to feed the growing world population. Nevertheless, without proper drainage provisions, this development can result in salinization and rising groundwater table problems in irrigated areas. An effective drainage system not only improves existing agricultural lands but also brings new areas under cultivation. Poor drainage and the associated salinization cause a reduction in crop growth and yield and this reduction will be much higher if both salinization and submergence occur simultaneously. Drainage is necessary for humid as well as dry regions and it is one of the main inputs to obtain better yields per unit of agricultural area. The provision of drainage has many direct and indirect effects. This paper provides an overview of the drainage and salinization problems of irrigated lands and their impact on overall agricultural productivity. The significance of the study along with its goals and the historical development of agricultural drainage is provided. The processes involved in drainage-associated salinization of irrigated lands and the effects of salinization and shallow groundwater tables on plant growth and yield and the environmental perspective of the problems are also detailed in the paper. Conclusions are provided that can be of use to the reader. (c) 2019 John Wiley & Sons, Ltd.