Study on effect of drip irrigation under membrane on the change of soil moisture and yield in cotton field.

[Objective]Based on practically measured data in field,to research effect of drip irrigation under plastic mulch on soil moisture change in cotton yield.[Method]according to different irrigation quota and irrigation times,the experiment is designed for 12 treatments.Using neutron soil moisture meter to measure the number of neutrons at the depth of 10,20,40,60,80,100 cm,one day later,the same process was repeated,and the number of neutrons was transformeed into soil moisture,and to compare yield of cotton with irrigation water productivity in different treatment at the same time.[Result]Under the condition of the 16 times irrigation and different treatment of irrigation quota,the change of moisture content before or after irrigation showed no significant difference at the depth of 10 cm.The occurrence of deep leakage of soil moisture was caused in cotton growth area when irrigating 10 times with irrigating quota of 4 500,1 500 m3/hm2,but no deep leakage of soil moisture happened under different treatment conditions.The cotton yield reached the highest when irrigating 16 times with irrigation quota of 3 900 m3/hm2.The effect of water saving reached 11.8% when irrigation 16 times with irrigation quota of 4 500 m3/hm2.The range of reduction yield was only 5.5% and 3.1% when irrigating 16 and 13 times.The water reproduction was higher when irrigating 2 and 10 times with irrigation quota of 3 900 m3/hm2,all of which reached over 1.6 kg/m3.[Conclusion]The bigger irrigation quota is,the fewer irrigation times.The more significant the increase tendency of the moisture rate after irrigation,the easier the deep leakage occurred.The bigger irrigation quota is,but the yield is not higher,it is not good for irrigation water productivity.However,the middle irrigation quota helped to increase the yield.For this reason,when irrigation scheduling is designed,moderate irrigation quota and irrigation times should be chosen,to improve yield of cotton and save water at the same time.