Tillage and Saline Irrigation Effects on Water and Salt Distribution in a Sloping Field

Abstract

Application of saline water using moving irrigation systems (MIS) can affect the water and salt distribution in the field and the crop yield because of runoff formation. The objective of this study was to determine the effects of tillage and water application methods on the distributions of water content, salt concentration in soil, and corn (Zea mays L.) yield under irrigation with saline water by MIS. The experimental site was located in a forage corn field in the Negev, Israel. Three tillage treatments were studied: (i) conventional tillage (control); (ii) microbasin; and (iii) diked furrows (dike). The control and the microbasin plots were irrigated with sprinkler MIS, and the dike plots with flooding MIS. The studied parameters were measured in five sampling sites located 25 m apart along the slope. The average dry canopy yields of the whole slope in the control, dike, and microbasin treatments were 21.7, 25.3, and 30.6 Mg ha−1, respectively, and their coefficient of variance (CV) values along the slope were 7.9, 5.7, and 3.5%, respectively. In the control treatment, soil water content increased from 0.12 kg kg−1 upslope to 0.19.0 kg kg−1 downslope. In contrast, no slope effect on soil water content was found in the microbasin and dike treatments. The electrical conductivity (EC) of the 0‐ to 0.3‐m soil layer in the control treatment increased in the downslope direction from 2.0 to 4.0 dS m−1 Conversely, in the microbasin and dike treatments, no consistent trend of the EC was observed with slope, and their average values were 3.4 and 7.0 dS m−1, respectively. It was suggested that these yield differences were related to the differences in the distribution of the soil water content and the salt concentration in soil within the field.