调亏灌溉对膜下滴灌菘蓝生长发育和产量的影响

2019年在河西绿洲冷凉灌区民乐县益民灌溉试验站进行了调亏灌溉对膜下滴灌菘蓝生长动态、产量和水分利用效率影响的大田试验研究。在苗期充分供水条件下,以全生育期充分供水(75%～85%的田间持水量)为对照,在营养生长期进行轻度、中度和重度水分调亏,在肉质根生长期进行轻度和中度水分调亏,在肉质根成熟期进行轻度水分调亏,分别测定了水分调亏菘蓝农艺性状的阶段性改变、干物质积累和分配、产量及水分利用效率。结果表明,在营养生长期和肉质根生长期对菘蓝进行中度和重度水分调亏、成熟期进行轻度水分调亏均会显著降低其株高、主根长、主根直径和叶面积指数(P0.05),而营养生长期和肉质根生长期对菘蓝进行轻度调亏其株高、主根长、主根直径和叶面积指数与对照处理间无显著差异(P0.05)。营养生长期以及肉质根生长期进行中度水分调亏和重度水分调亏会降低菘蓝干物质积累量,降幅为3.11%～15.67%,而轻度水分调亏则不会显著影响其干物质积累量。WT1和WT4处理的经济产量与对照无显著差异,其值分别为8 554.18,8 398.70 kg/hm~2,其他各处理均导致菘蓝经济产量降低,降幅为6.89%～18.33%,WT4处理的水分利用效率和灌溉水利用效率最高,比对照提高7.91%和7.39%。因此,在营养生长期—肉质根生长期施加连续轻度水分调亏,其他生育期充分供水是实现河西绿洲冷凉灌区菘蓝节水高产高效灌溉制度。

Effects of Regulated Deficit Irrigation on Growth and Yield of Isatis indigotica Under Mulched Drip Irrigation

A field experiment was conducted to study the effects of regulated deficit irrigation on growth dynamics,yield and water use efficiency of Isatis indigotica under mulched drip irrigation in 2019 at Hexi oasis cold irrigation area of Yimin irrigation experimental station,Minle County. Under the condition of ensuring adequate water supply in seedling stage,full water supply in whole growth stage (75%~85% field water capacity) was taken as the control treatment. Mild,moderate and severe water deficit management was carried out in the vegetative stage,mild and moderate water deficit treatment was carried out in the fleshy root growth stage,and mild water deficit treatment was carried out in the fleshy root maturity stage. The periodical changes in agronomic traits,dry matter accumulation and distribution,yield and water use efficiency of I. indigotica were measured under different water deficit treatments. The results showed that the plant height,taproot length,taproot diameter and leaf area index of I. indigotica decreased significantly (P<0.05),on moderate and severe water deficit during vegetative stage and fleshy root growth stage and light water deficit during fleshy root maturity stage. There was no significant difference in plant height,taproot length,taproot diameter,and leaf area index with the control treatment between the vegetative stage and fleshy root growth stage under mild water deficit treatment (P>0.05). Moderate water deficit and severe water deficit in vegetative stage and fleshy root growth stage could reduce dry matter accumulation of I. indigotica. The decrease ranged from 3.11% to 15.67%. Mild water deficit treatment would not significantly affect dry matter accumulation. There was no significant difference between the economic yield of WT1 and WT4 with control treatment (P>0.05). Their values were 8 554.18 kg/hm² and 8 398.70 kg/hm². All other treatments reduced the economic output of I. indigotica. The decrease ranged from 6.89% to 18.33%. Water use efficiency (WUE) and irrigation water use efficiency (IWUE) in WT4 were the highest. Compared with the control treatment,it was improved by 7.91% and 7.39%. Therefore,applying continuous mild water deficit during the vegetative stage and the fleshy root growth stage and providing adequate water supply during the other growth stages is an optimal irrigation method with high efficiency,water saving,and high yield in the irrigation area of Hexi oasis cold irrigation area.