土壤水分调亏处理膜下滴灌马铃薯耗水特征及生长动态

以青薯"168"为试验材料,通过大田试验,研究了膜下滴灌调亏对河西绿洲马铃薯土壤水分动态、耗水特征、生长动态及产量的影响。试验设5个水分调亏处理,即块茎形成期和块茎膨大期分别进行轻度(55%~65%田间持水量,FC)和重度(45%~55%FC)调亏,淀粉积累期轻度(55%~65%FC)调亏,以全生育期充分供水(65%~75%FC)为对照。结果表明:受水分调亏影响,上层0~40 cm土壤水分变化较下层40~60 cm明显,马铃薯块茎膨大期经受轻度和中度水分亏缺土壤贮水量显著(P0.05)低于充分供水8.1%和18.7%,耗水强度则显著降低60.0%和73.0%。块茎形成期进行不同程度水分调亏后复水,其叶面积指数(LAI)、光合势(LAD)、相对生长率(RGR)均表现出补偿效应,而块茎膨大期进行轻度和中度水分调亏以及淀粉积累期轻度水分调亏LAI、LAD及RGR均呈下降趋势,其薯块产量与全生育期充分供水相比分别降低22.3%、26.5%、38.7%。因此,马铃薯生长后期应注重供水以延长绿叶面积,对作物产量的形成有利。

Water consumption characteristics and growth dynamics of potato under mulched drip irrigation with soil water deficit regulation

An experiment was conducted to determine the effect of water deficit on soil moisture,water consump tion,growth,and tuber yield of potato under mulched drip irrigation in Hexi oasis region,with "Qingshu No.168" selected as the experimental cultivar.There were mild (55％ ～ 65％ of field capacity,FC) and medium water deficit (45 ％ ～ 55 ％ FC) at both tuber initiation and tuber bulking stages,mild water deficit at tuber starch accumulation stage,resulting in five water deficit treatments.The non-soil-water-deficit (65 ％ ～ 75 ％ FC) was taken as control.Results indicated that soil water content varied more in 0 ～ 40 cm than 40 ～ 60 cm soil layer.The stored soil water for the mild and medium deficit at potato tuber bulking was 8.1％ and 18.7％ lower than that for full irrigation(P ＜ 0.05),and the daily water consumption decreased by 60.0％ and 73.0％ respectively.The leaf area index (LAI),leaf area duration (LAD),and relative growth rate (RGR) of potato were compensatory increased by re-watering after various water deficit at tuber initiation,while the LAI,LAD,and RGR decreased in the plants subjected to mild and medium water deficit at tuber bulking and mild deficit at starch accumulation,with tuber yield reduced by 22.3 ％,26.5 ％,and 38.7 ％ compared with that of full irrigation.Therefore,green leaf area should be maintained by sufficient water supply at late growth stages of potato,which is beneficial to tuber yield.