Effect of low and high irrigation water salinity on the soil moisture content distribution and corn crop productivity using double drip irrigation system.

Abstract

A field experiment was conducted during the autumn season of 2016 at the research station of College of agriculture, University of Basrah, Iraq. The soil texture was clay. The aims of the experiment were to study the effect of two irrigation water salinity levels, which were low water salinity (3.00-3.60 DSm-1) and high water salinity (7-8 DSm-1) and soil amendments on the soil moisture distribution and the yield of corn crop (Zea mays). The irrigation treatments included six treatments using the proposed double drip irrigation system. These treatments are first 100% high water salinity, second 100% Low water salinity, third 50% high water salinity plus 50% low water Salinity (remained constant along the growth season), fourth 50% low water salinity plus 50% high water salinity (variable), fifth 25% low water salinity plus 75% high water salinity and sixth 75% low water salinity plus 25% high water salinity. 20% irrigation water was added as leaching requirements. The soil amendment treatments are: first (0.2% fuel oil plus 0.2% lubrication oil) used on dry weight after they were emulsificated with irrigation water and applicated as a single treatment, second animals manure (2% amendment after C / N adjustment and third the control treatment. The treatments were applicated using RCBD. At the end of growth season of the corn crop the results showed that the moisture content of the soil increased as the amount of the water salinity increased and when the soil amendments were added to the soil. The animal manure surpassed the fuel oil plus lubrication oil in increasing the soil ability in moisture retention. The corn crop yield increased significantly when low water salinity was used with amendment addition. The gravimetric moisture content decreased as the lateral distance increased away from the driper. The highest moisture content was recorded for depth of (15-30 cm).