Effects of field rainwater harvesting on the physiology, growth and yield of winter wheat

Based on the field experiment conducted in 2004～2005 in Changping, Beijing, the effects of field rainwater harvesting on the soil moisture, physiology, growth and yield of winter wheat were studied. Results show that when the rainfall closes to that of normal year and harvesting area accounts for 40% of the total planting area, soil water is improved significantly and water consumption increases by 6.5%～9.8% compared with the control in 0～160 cm soil depth. Meanwhile, the deep soil water utilization is 6.9～7.3 times that of the control. Leaf photosynthesis and transpiration improve 10.1%～46.4% and 21.5%～60.5% respectively over the control; stomatal resistance in contrast decreases by 23.3%～45.3%, the maximum light convertion efficiency of PSII and its potential activity increase by 2.1%～42.6 % and 10%～353%. The enhanced growth was also observed. Plant height, leaf area indexes and dry matter accumulation at harvesting time increase by 15%～39%, 58.2%～112%, and 27%～44%, respectively. Consequently, grain yield of winter wheat increases by 36%～42%. When water supply is limited to 1 m and 1.6 m, the water production efficiency increases by 39.5%～50.5% and 23.5%～33.5% respectively. Though the additional use of water absorbent further improves the soil water and the growth of winter wheat over the rain harvesting treatment alone, but it has little effect on the yield.