膜下滴灌灌溉制度对棉田土壤水分变化及产量的影响研究

Study on Effect of Drip Irrigation under Membrance on the Change of Soil Moisture and Yield in Cotton Field

【目的】以田间实测数据为基础,研究膜下滴灌灌溉制度对土壤水分变化及棉花产量的影响。【方法】试验根据不同灌溉定额和不同灌水次数设计了12个处理,在灌水前1d利用中子土壤水分仪测定宽、窄行的10、20、40、60、80和100cm深度处中子数,灌水间隔1d后重复此过程,然后将中子数转换为土壤含水率,同时将不同处理条件下棉花产量和灌溉水分生产率进行对比。【结果】灌水次数为16次,不同灌溉定额处理下,10cm深度处灌水前后宽窄行土壤含水率变化不明显。灌水次数为10次,灌溉定额为4500、5100m3/hm2时,棉花生长区域土壤水分出现了深层渗漏,而其它处理条件下,均未出现深层渗漏。灌溉定额为3900m3/hm2,灌水次数为16次的处理产量最高,灌溉定额为4500m3/hm2的处理节水效率达到11.8%,在灌水次数为16、13次时,减产幅度仅为5.5%和3.1%。灌溉定额为3900m3/hm2的2、10处理水分生产率较高,均在1.6kg/m3以上。【结论】灌溉定额越大,灌水次数越少,灌水后宽窄行含水率增大趋势越明显,越容易出现深层渗漏。灌溉定额越大,产量并不是越高,其灌溉水分生产率也不是很好,而中等灌溉定额的产量较高,灌溉水分生产率也是最好的。因此,设计灌溉制度时,应尽量选择中等灌溉定额和灌水次数,同时达到提高产量和节水的效果。

[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.