农田排水与淡水交替灌溉对枣树生理特性及品质的影响

Efficacy of Alternate Irrigation with Drainage-water and Freshwater on Photosynthetic Traits and Quality of Jujube

南疆地区农田灌溉洗盐和种稻改良致使排水过多,排水下泄对塔里木河以及地下水环境造成危害。故尝试利用农田排水在缺水时期作为补充水源对枣树进行灌溉,一方面可以提供作物所需水分,另一方面减少排水下泄。【目的】分析农田排水—淡水交替灌溉下枣树的生理特性和品质。【方法】采用农田排水(Farmland Drainage,FD)与淡水(Fresh Water,FW)交替灌溉(Alternative Irrigation,AI)的试验方法,设计了AI1(FD-FD-FW-FD)、AI2(FD-FDFW-FW)和AI3(FD-FW-FW-FD)3种交替灌溉次序,测定了不同时期农田排水与淡水交替灌溉后连续4 d的枣树光合速率、气孔导度,以及果实品质相关指标,并分析了枣树的水分利用效率。【结果】(1)连续2次用FD灌溉会显著降低枣树光合速率和气孔导度,随后交替灌溉1次或2次FW的枣树叶片气孔导度没有显著提升;(2)FD灌溉后连续2次用FW灌溉,枣树光合速率和气孔导度明显提高,再次FD,枣树气孔导度降低不明显;(3)不同交替灌溉处理的叶片水分利用效率的变异系数大小依次是CK<AI3处理<AI2处理<AI1处理;(4)不同处理通过极值标准化法的红枣果实品质综合评价值的大小顺序是AI2处理>CK>AI3处理>AI1处理。【结论】在利用FD进行枣树交替灌溉时,应减少连续的FD灌溉次数,使之间隔灌溉,在间隔期连续多于2次的FW灌溉的枣树生理特性较CK略有降低,但品质综合评价较CK有所提高。

Salt-affected soils in Xinjiang are often remediated by irrigation-washing or rice cultivation, with their leachate discharged to groundwater or the Tarim River. We have investigated the feasibility of using the leachates as supplementary water to irrigate jujube trees when water is in serious shortage.【Objective】Analyze the photosynthetic traits and quality of Jujube under alternative irrigation with drainage-water and freshwater.【Method】The technique is to alternate irrigation with the leached drainage（FD） and freshwater（FW）. We examined three alternate schemes： FD-FD-FW-FD（AI1）, FD-FD-FW-FW（AI2）, and FD-FW-FW-FD（AI3）. In each treatment, we measured the photosynthetic rate and stomatal conductance of the jujube at different growth stages. We also analyzed the water use efficiency as well as fruit quality and index after harvest.【Result】（1）Two successive FD considerably decreased the photosynthetic rate and the stomatal conductance, and the stomatal conductance was unable to recover even after two FW following two successive FD.（2）Two FW followed by one FD significantly improved the photosynthetic rate and the stomatal conductance, but the stomatal conductance decreased if FD was applied again.（3） The variation coefficient of water use efficiency ranked the treatments in CK〈AI3 〈AI2〈AI1. The fruit quality calculated using the extremum normalization method ranked the treatments in AI2〉CK〉AI3〉AI1.【Conclusion】Using FD for Jujube should alternate FD and FW rather than successively use FD for more than once. Alternating FD and FW more than twice decreased the physiological characteristics but improved the quality of the jujube, compared to the CK.