Effects of Supplemental Irrigation Based on Measurement of Soil Moisture Content on the Photosynthesis and Grain Yield of Winter Wheat

In order to provide the theoretical basis for wheat water-saving and high yield production in huang-huai winter wheat area,an experiment of supplemental irrigation at wintering stage(target soil relative moisture content=75%),jointing stage(target soil relative moisture content=70%),and anthesis stage(target soil relative moisture content=75%)based on the soil moisture measured in four soil layers(0~20cm,D1;0~40cm,D2;0~60cm,D3;and 0~140cm,D4)were designed to study the effects of supplemental irrigation based on the measurement of soil moisture content in different soil layers on the photosynthesis and grain yield of winter wheat under the field condition.The results showed that the irrigation amount at the wintering,jointing,and anthesis stages and the total irrigation amount of D2 treatment were more than that of D1 and D4treatments,while the irrigation amount at the jointing stages and during whole growing stage of D2 treatment were less than that of D3 treatment.The photosynthesis rate in D2 and D3treatments was higher than that of D4 treatment,and the sucrose phosphate synthase(Sps)activity,the socrose content in flag leaves and the amylopectin content and total starch content in grain of D2 and D3treatments were higher than that of D1 and D4treatments.There were no significant differences in 1 000 grain weight and grain yield between D2 and D3treatments,but which were higher than that of D1 and D4treatments,and the water use effi-ciency of D2 and D3treatments were higher than that of D4 treatment.To consider the irrigation amount,grain yield,and water use efficiency comprehensively,D2 treatment could be the optimal treatment under the experimental condition.