Evaluation of water requirement and improvement of rainfall productivity and grain yield of dryland wheat genotypes in different crop managements

To evaluate rainfall productivity and grain yield of dryland wheat genotypes under different rotation and tillage managements, a split-split plot experiment based on RCBD with three replications was conducted in Dryland Agricultural Research Institute for 4 years (2016-20). Three crop rotations (chickpea-wheat, safflower-wheat, and vetch-wheat) were located in main plots and three different tillage methods (conventional, minimum, and zero tillage) were considered in subplots and two Baran and Azar 2 wheat genotypes were considered in sub-sub plots. Results indicated tillage and crop rotation treatments significantly affect precipitation efficiency. Maximum rainfall productivity was recorded for Baran in zero and minimum tillage systems with forage (vetch) rotation by 0.71 and 0.7 kg/m3. Rainfall productivity under zero tillage treatment during three years of the experiments increased from 0.45 up to 0.67 (approximately 32 %). The highest relative water content, stomatal conductance and harvest index were recorded from Baran in vetch rotation under zero tillage treatment. The highest grain yield was belonged to the vetch, chickpea and safflower rotations by 2231, 2105 and 1991 kg/ha, respectively. With increasing soil water content and improving rainfall productivity in the conservation agriculture system, grain yield was increased by 5% and 8 % under minimum and zero tillage treatments than that of a conventional system. Therefore, in cold rainfed climates, in order to develop in wheat conservation, it is recommended to the application of autumn forage and chickpeas rotation in zero tillage conditions.