Water Productivity Improvement Under Salinity Conditions: Case Study of the Saline Areas of Lower Karkheh River Basin, Iran

Abstract

Soil salinity and low drainage capacity are major factors limiting crop yield and low agricultural water productivity (WP) in the Lower Karkheh River Basin (L-KRB) in the southwest to south of Iran. The objective of this chapter is to provide and elaborate cost-effective and adaptive solutions and measures for the amelioration of the situation and for enhancing WP in this area. The suggested approaches and measures are based on field experiments conducted both under farmer’s field and research station. The main cultivated crop in the region is wheat. For the first step, WPs of wheat were determined under some farmer’s fields. Based on results, WP of wheat in the area varied between 0.24 and 0.77 kg/m3. The study aimed to provide simple measures and management practices for reducing salinity and waterlogging hazards and ultimately improving crop WP in the studied area. The focus of experiments was on the methods of land preparation for irrigation, sowing methods by the different adapted machines, and seeding rates. Changing of traditional basin irrigation to a modern mixed system of border-basin irrigation method could improve irrigation performance and will reduce applied water greatly and hence could improve WP. Construction and provision of fixed and low-cost water intake structures on farm ditches could have more impacts on the improvement of irrigation performance as well. Optimum (modern) border irrigation and optimum basin treatments had higher WPs (1.36 and 1.04 kg/m3, respectively) than the traditional irrigation practiced by the farmers (0.61 kg/m3). Although the WP of optimum border was highest, the basin irrigation method is suggested because this method is more adaptive and sustainable in terms of acceptance by the local farmers.