Coupling effects of deficit irrigation (DI) in different growth stages and different nitrogen applications on the root growth, yield, WUE of eggplant | 不同生育期水分亏缺和施氮量对茄子根系生长、产量及水分利用效率的影响

صينى. 研究3个不同生育期水分亏缺和施氮量对茄子根系生长、空间分布及产量和水分利用效率的影响。利用盆栽试验，设置低氮（N1，0.1 g/kg）、中氮（N2，0.3 g/kg）、高氮（N3，0.5 g/kg） 3个施氮水平，分别在茄子开花坐果期、初果期、盛果期3个不同生育期进行水分亏缺处理，以不亏水处理为对照（CK），共12个处理，对不同生育期水、氮处理茄子的总根长、总根干质量和鲜质量、产量及水分利用效率进行测定，并建立相应的水分生产函数。在施氮量相同的情况下，与不亏水处理相比，盛果期水分亏缺N1、N2和N3处理对总根长和总根干质量影响显著，其中茄子总根长较对照分别降低了12.39%，18.82%和15.29%，总根干质量分别下降了42.31%，33.46%和25.42%。与对照相比，开花坐果期、初果期、盛果期水分亏缺处理茄子的总根鲜质量在N1处理下分别较对照降低了21.86%，9.35%和39.03%；N2处理下，分别降低了2.7%，14.99%和48.23%；N3处理下，分别降低了41.1%，3.7%和35.07%。与对照相比，开花坐果期、初果期、盛果期水分亏缺处理茄子的产量在N1处理下，分别较对照降低了6.13%，10.84%和14.64%；N2处理下，分别降低了3.94%，5.62%和11.6%；N3处理下，分别降低了11.35%，4.23%和16.14%。随着施氮量的增加，所有处理总根长、总根干质量、鲜质量和产量均呈现先上升后下降的趋势。在低氮和中氮条件下，开花坐果期水分亏缺处理既获得了较高的产量，也实现了较高的水分利用效率。茄子根系干质量在垂直方向上呈对数递减趋势；盛果期水分亏缺对各层根系分布的影响最大；随着施氮量的增加，根系分布呈现高氮浅根化趋势。在N1和N2处理下，水分敏感指数在盛果期最大，其次是初果期和开花坐果期；在N3处理下，各水分敏感指数的大小顺序依次为盛果期＞开花坐果期＞初果期。茄子对盛果期的水分亏缺最为敏感，该时期亏水不仅限制了根系的生长和空间分布，而且降低了茄子的产量；在低氮和中氮条件下，开花坐果期的水分亏缺对茄子根系生长发育、产量的影响较小，而且获得了较高的水分利用效率。与低氮和高氮相比，中等施氮水平有利于茄子根系的生长及产量和水分利用效率的提高。

إنجليزي. This research was to explore the coupling effects of deficit irrigation at different growth stages and different nitrogen fertilizer applications on root growth, spatial distribution, yield and WUE of eggplant. Four irrigation modes were designed as T1 (DI in blossom and fruit-set period), T2 (DI in the first fruit period), T3 (DI in the full bearing period and CK (Normal irrigation) with three N application levels, N1(0.1 g/kg), N2 (0.3 g/kg), N3 (0.5 g/kg), through which root length, root volume, root fresh weight, root dry weight, yield and water use efficiency were studied and water production function was built. Compared with CK, under the same application amount of nitrogen fertilizer, treatments of DI at the full bearing period were significantly influenced and the total root length decreased 12.39%, 18.82%, 15.29% respectively and the total root dry weight decreased 42.31%, 33.46%, 25.42% respectively. Compared with CK, treatments of DI at blossom and fruit-set period, the first fruit period, and full bearing period were significantly influenced and under N1 condition, the root fresh weight decreased 21.86%, 9.35%, 39.03%; under N2 condition, it decreased 2.7%, 14.99%, 48.23%; under N3 condition, it decreased 41.1%, 3.7%, 35.07% respectively. Compared with CK, the yield of treatments of DI at blossom and fruit-set period, the first fruit period, and full bearing period were significantly influenced and under N1 condition, the yield decreased 6.13%, 10.84%, 14.64%; under N2 condition, it decreased 3.94%, 5.62%, 11.6%; under N3 condition, it decreased 11.35%, 4.23%, 16.14% respectively. With the increase of nitrogen fertilizer application, root length, root dry weight, fresh weight and the yield of all treatments rose steadily and reached the peak at middle nitrogen fertilizer application level and with the further increase of nitrogen application, data of all treatments began to fall down. At N1 and N2 levels, treatments of DI at blossom and fruit-set period obtained high WUE on the basis of high yield. Root weight logarithmically reduced in the vertical direction of soil layers. With the increase of nitrogen fertilizer application, root inclined to distribute in shallow soil layers. Under N1 and N2 levels, water sensitivity index of DI in the full bearing period was the highest, followed by treatments of DI in the first fruit period and DI in blossom and fruit-set period, while under high nitrogen application level, water sensitivity index of DI in the first fruit period increased remarkably. The eggplant was most sensitive to deficit irrigation at the full bearing period, which not only restrained root growth and spatial distribution, but also significantly reduced the yield. At low and middle nitrogen fertilizer application level, treatments of DI at blossom and fruit-set period were lightly affected by DI and finally, high WUE was obtained on the basis of high yield. Moderate nitrogen level positively affected root growth, the yield and WUE of eggplant.