Effects of growth-stage-based deficit irrigation management on physiological and biochemical characteristics and yield of winter wheat in Northwest China*

Growth-stage-based deficit irrigation is an appropriate method when irrigation water is scarce. However, the effects of continuous deficit irrigation during the winter wheat growth period on crop physiological and biochemical processes need to be further evaluated. Five growth-stage-based deficit irrigation strategies were established and tested in winter wheat in the present study. The results showed that water stress resulted in a decrease in net photosynthetic rate (Pn) and transpiration rate, but led to an increase in catalase and peroxidase activities and an increase in malondialdehyde and proline contents. A high Pn could be sustained when the relative water content of the soil was maintained within the range of 60%-75%. Pn was negatively correlated with antioxidant enzyme activity. Based on the averaged data from 2017 to 2019, all water stress treatment groups showed varying degrees of yield reduction compared to the control (CK). Though the T1 treatment (i.e., irrigation from jointing stage to filling stage with 240 mm of water) had the highest water productivity (2.19 kg m(-3)), its grain yield was only 7.01% lower than the CK treatment. The present results suggest that the T1 treatment is the better irrigation model for saving water and achieving high grain yield in winter wheat in this region.