不同灌水下限对枣树光合特性、产量及品质的影响

The Impact of the Critical Soil Moisture Used for Scheduling Deficit Drip Irrigation on Photosynthesis, Yield and Quality of Jujube Tree

【目的】探究滴灌条件下适合沙漠绿洲区枣树生长发育的灌水下限。【方法】采用大田试验,设置4种不同灌水下限T1、T2、T3和T4(分别为田间持水率的40%、55%、70%和85%),分析其对枣树不同生育阶段的光合特性、产量及品质的影响。【结果】灌水下限的降低使得净光合速率、蒸腾速率、气孔导度降低,但是会提高枣树的叶片水分利用效率。总体来说,T3处理的净光合速率值最高,且T2处理的叶片水分利用效率在枣树各生育阶段均较高。随着灌水下限的降低,提高了果实的总糖、可溶性固形物、糖酸比等品质指标;当灌水下限为田间持水率的55%时,枣树的单果质量和产量相对较高,分别为4.43 g和6832.9 kg/hm2。【结论】综合考虑枣树的光合特性、产量及品质,建议灌水下限设置为田间持水率的55%,枣树的叶片水分利用效率显著提高,同时获得较好的红枣产量和品质。

【Objective】Deficit irrigation is a water-efficient irrigation method in arid and semi-arid region to improve water use efficiency,but how to determine the optimal deficiency in scheduling the irrigation remains elusive.The purpose of this paper is to examine the effect of the critical soil moisture–a soil water content to resume irrigation whenever measured soil moisture drops below it-on growth of jujube tree in a desert oasis.【Method】Field experiment was conducted in Xinjiang,in which we compared four critical soil moistures:40%(T1),55%(T2),70%(T3)and 85%(T4)of the field capacity.In each treatment,we measured photosynthesis,yield and fruit quality of the jujube at different growth stages.【Result】Decreasing the critical soil moisture reduced net photosynthetic rate,transpiration rate and stomatal conductance,but enhanced leaf water use efficiency.Among all treatments,T3 gave the highest net photosynthetic rate and T2 was most efficient in leaf water use at all growth stages.Increasing the critical soil moisture improved fruit quality indexes such as total sugar,soluble solids and sugar-acid ratio.Single fruit weight and yield both peaked when the critical soil moisture was set at 55%of the field capacity,reaching 4.43 g and 6832.9 kg/hm2 respectively.【Conclusion】In terms of photosynthetic rate,yield and fruit quality,setting the critical soil moisture at 55%of the field capacity can significantly improve leaf water use efficiency,yield and fruit quality of the jujube.