绿洲膜下滴灌调亏马铃薯水分生产函数及灌溉制度优化

Water production function and optimization in irrigation schedule of potato with mulched drip irrigation under water deficit in oasis region

通过田间试验研究了绿洲膜下滴灌调亏马铃薯各生育期耗水规律及其影响因素,建立了以Jensen模型为基础的水分生产函数并对马铃薯灌溉制度进行了优化。结果表明:块茎膨大期马铃薯水分敏感指数最大,块茎形成期次之,苗期和淀粉积累期较小;块茎形成期轻度调亏对马铃薯产量无显著影响(P>0.05),而块茎形成期中度调亏、块茎膨大期轻度和中度调亏对其产量均有显著影响(P<0.05);块茎形成期轻度调亏的水分利用效率比块茎形成期中度调亏、块茎膨大期轻度调亏和全生育期充分灌水分别提高了6.2%、8.3%和6.7%;膜下滴灌调亏马铃薯产量随耗水量增加而增加,水分利用效率随之降低,全生育期充分灌水比块茎膨大期中度水分调亏耗水量增加22.4%,产量增加20.4%,水分利用效率降低14.0%。采用遗传算法并结合水分生产函数进行灌溉制度优化,结果表明:河西绿洲区膜下滴灌马铃薯全生育期灌溉定额为225 mm时,产量最高,为43.86 t·hm-2,灌溉水利用效率为19.5 kg·m-2;灌溉制度为苗期灌水20~30 mm,块茎形成期灌水70~75 mm,块茎膨大期灌水100~115mm,淀粉积累期灌水20~25 mm,灌水间隔为7 d。因此,膜下滴灌调亏在降低马铃薯耗水量的同时,提高了水分利用效率,在块茎形成期轻度水分调亏不影响产量,可达到节水增产的目的。

A field experiment was conducted to test the potato periodic evapotranspiration and its influencing factors with mulched drip irrigation under water deficit regulation（ WDR） in oasis irrigation region. Crop water production function based on Jensen model was established,and the optimal irrigation schedule for potato was determined. The results showed that the sensitive index was found the largest at the tuber bulking stage,followed by the tuber initiation stage and relatively small at the establishment and potato starch accumulation stages. Potato yield was not decreased by low WDR plots during tuber initiation（ P〉0. 05）,but was significantly decreased in the medium WDR plots during tuber initiation and low and medium WDR plots during tuber bulking（ P〈0. 05）. The water use efficiency（ WUE） was maintained in low WDR potato during tuber initiation,significantly improved by 6. 2%,8. 3% and 6. 7% from that in medium WDR plots during tuber initiation,low WDR plots during tuber bulking and full irrigation plots（ CK）,respectively. With the increase of crop evapotranspiration,the potato bulb yield became increased,while the water use efficiency was decreased. Crop evapotranspiration was increased by 22. 4%,the potato bulb yield was increased by 20. 4% and the WUE went decreased by 15. 7%. The optimal irrigation system established by genetic algorithm with crop water production function showed that the highest potato bulb yield（ 43. 86 t·hm^-2） could be achieved when the irrigation depth was upto 225 mm in the Hexi oasis,and irrigation WUE was 19. 5 kg·m^-2. The recommended amount of irrigation is 30 - 40,130 - 140,170 - 190 mm and 25 mm at the stages of establishment,tuber initiation,tuber bulking and potato starch accumulation,respectively,and the irrigation intervals are 7 days. Therefore,when WDR under mulched drip irrigation reduces potato water consumption,the water use efficiency can be enhanced. Low WDR does not affect the potato yield during tuber initiation,reaching water-saving purposes.