宁夏中部干旱带覆膜沟灌玉米灌溉制度研究

Study on Film Furrow Irrigation Schedule for Corn Central Arid Regions of Ningxia

在宁夏中部干旱带设立试验区，以覆膜沟灌玉米为研究对象，设置不同水分处理进行田间试验，依据作物根区土壤水贮存量、生理指标及产量水平等参数，研究确定合理覆膜玉米沟灌灌溉制度。结果表明：沟灌玉米O～60cm土层土壤水变化幅度最大，20~40cm是主要贮水层，不同水分处理贮水量变幅为3~138．8m3／hm2；光合有效辐射呈抛物线形规律变化，灌水后均有所下降；蒸腾速率呈单峰型，水分处理不同蒸腾速率峰值出现时间不同；高水分处理玉米净光合速率较高，且有明显“午休现象”；灌溉定额3900m3／hm2时产量最高为15300kg／hm2，2700m3／hm2时产量最低为13770kg／hm2，灌溉水量在一定范围内可增产，但超出上限时，产量与灌水不呈正相关关系。宁夏中部干旱带覆膜沟灌玉米合理灌溉制度为：全生育期灌水4次，灌水定额为975m3／hm2，灌溉定额3900m3／hm2。

The experimental points were set up in the central arid regions of Ningxia, the corn under film furrow irrigation was taken as studying object, and different water treatments were set in the field experiment to study the rational film furrow irrigation sched- ule for corn according to the crop root zone water storage, physiological index, yield levels and other parameters. The results showed that： for corn under film furrow irrigation, the change amplitude of the soil water in 0~60 cm layer was the largest, the main stor- age layer of corn＇s root zone was in 20~40 cm, and the soil water storage variation range of different treatment was from 3 to138.8 m3/hm2 ; the photosynthetic effective radiation changed in the parabolic law and all decreased after irrigation; the transpiration rate variation showed a single-peak curve, the peak value appeared at different time for different treatments; the net photosynthesis rate of the high water treatment was higher and had an obvious ＂midday depression＂ ; the yield could be up to 15 300 kg/hmz when the ir- rigation quota was 3 900 ma/hmz, while the yield would be low to 13 770 kg/hm2 when the irrigation quota was 2 700 ma/hm2 ;the irrigation with a certain range amount could increase yield, but the yield was not positively correlated with irrigation when the irriga- tion amount was beyond the upper limit; the optimal irrigation schedule of the film furrow irrigation for corn in the central arid area of Ningxia is that the irrigation times during the whole growth period is 4, the irrigation water amount of each irrigation is 975 m3/ hm2, and the irrigation quota is 3 900 m3/hm2.