The effects of saline water and soil tillage on the salt and water regimes in a sloping cornfield using a moving irrigation system

Moving irrigation systems in soils with low infiltrability generate high amounts of runoff. Therefore, tillage practices are applied to increase the surface storage capacity of the field and improve the distribution uniformity of the water. When saline water is used, sprinkling over the canopy might be harmful to the growth, and a direct application of the water to the soil surface might be advantageous. In this study, the interaction between tillage practices and water application methods are compared in terms of yields and soil water and salt content distribution with depth in a cornfield irrigated with saline water. Also, the effect of slope is considered. The treatments are: (i) control, where the soil surface is not treated; (ii) microbasins (pits) constructed on the soil surface between the rows; (iii) dikes erected across the furrows every two rows. The control and microbasins treatments are irrigated with a moving sprinkler system while water is applied directly to the soil surface in the dikes treatment. The lowest yield is obtained in the control plots. Compared to it, the yields increase by 41% and 17% in the microbasins and the dike treatments, respectively. In terms of water and salt contents, a slope effect is observed in the control plots, the values down slope being the highest at all depths. No slope effect is obtained in the two tillage practices. The water and salt content distributions with depth are weighted using the water extraction distribution of corn grown in the Northern Negev. The weighted water contents are practically similar for the two tillage practices and are higher than for the control. The weighted salt contents are the highest for the dikes and practically similar for the microbasins and the control. The combined effect of the water and the salt contents explains the differences in terms of yields.