Effects of water applications and soil tillage on water and salt distribution in a Vertisol

Under limited water resources, modern irrigation methods tend to save water and improve water and salt regimes within the root zone. This study deals with the combined effects of water application methods and tillage practices on water and salt distributions, runoff production, and soil loss in a field irrigated with moving irrigation systems (MIS). An experiment was conducted in a cotton (Gossypium hirsutum L. cv. Sivon) field at Hazorea, Israel, where the main soil type is vertisol (Typic Chromoxerets). Sprinkling (SP) and flooding (FL) MIS, and conventional (CT) and microbasin (MB) tillage, were compared in terms of runoff and soil loss from runoff microplots (5 m(2)), soil water content and salinity distribution with depth, yield, and plant height. Under SP conditions, no runoff and soil loss were obtained for either tillage practice. In the FL/CT treatment, the mean runoff and soil loss were about 25% of the irrigation water and 0.59 kg m(2). The FL/MB treatment reduced the runoff and soil loss to 5.8% and 0.02 kg m(-2), respectively. The soil water contents in the SP treatments were generally lower than in the FL treatments, especially in the 0.1- to 0.6-m soil layer. No significant differences in the soil salinity, plant height, and seed-cotton yield were observed between the treatments. Microbasins tillage reduces water losses under flooding MIS to a point where they become practically similar to those obtained under sprinkler MIS. It can potentially lead to lower water losses if the microbasins storage capacity is matched to the water application rate, to avoid runoff.