不同灌水量对滴灌猕猴桃光合、产量与水分利用效率的影响

【目的】揭示不同灌水量对滴灌猕猴桃生长、产量及水分利用效率的调控效应。【方法】以7 a生金艳猕猴桃为试材,在果实膨大期(Ⅲ期)、果实成熟期(Ⅳ期)各设置1个对照(CK)和4个灌水处理,即高水(HW)、中水(MW-1)、偏低水(MW-2)和低水处理(LW),灌水量分别为CK的55%、65%、75%和85%。【结果】猕猴桃叶片光合特性因生育期和灌水量的不同而呈现明显差异,其光合速率(Pn)、蒸腾速率(Tr)和气孔导度(gs)均随灌水量的减小而减小,但Ⅲ-HW、Ⅳ-HW处理的Pn与CK差异不显著(P>0.05),Ⅲ-HW和Ⅳ-MW-2处理的瞬时水分利用效率较CK分别显著提高了2.70%、5.41%(P<0.05);各处理猕猴桃产量较CK仅下降0.09%～6.24%,产量水分利用效率(WUEy)则提高了2.82%～23.16%,其中Ⅲ-HW、Ⅳ-MW-1处理产量仅下降了0.09%、2.45%,而WUEy提高了2.82%、10.73%。【结论】滴灌猕猴桃果实膨大期高水处理、果实成熟期中水处理保持产量无明显下降,有效提高WUEy,并节水2.50%、11.62%(分别节水156、726 m3/hm~2),具有较好的节水稳产效果。

The Effects of Drip-irrigation Amount on Photosynthesis,Yield and Water Use Efficiency of Kiwifruit

【Objective】This paper aims to provide a drip irrigation schedule during fruit expansion(Ⅲ) and fruit maturity stage(IV) of a seven-year old Jin Yan kiwi, based on the effects of irrigation amount during the two stages on photosynthesis, grain yield and water use efficiency of the kiwi.【Method】The field experiment examined five irrigation amounts: sufficient irrigation(CK), high irrigation using 85% of water used in CK(HW), middle irrigation using 75% of water used in CK(MW-1), moderate irrigation using 65% of water used in CK(MW-2),and low irrigation using 55% of water used in CK(LW).【Result】Deficit irrigation had a significant impact on photosynthesis, with the photosynthetic rate, transpiration rate and stomatal conductance all decreasing as water deficiency increased. The instant water use efficiency under water deficiency was-4.83% to 14.05% higher than that under CK, and the photosynthetic rate under Ⅲ+HW and Ⅳ+HW treatment was not significantly lower than that under CK(P>0.05), being 5.09 μmol/(m2· s) and 5.99 μmol/(m2· s) respectively. The yield under water deficit irrigation was 11 066.7～10 385.6 kg/hm~2, only 0.09%～6.24% lower than that under CK but increasing water use efficiency by 2.82%～23.16%. The water deficiency in III+HW and IV+MW-1 reduced the yield by 0.09% and2.45% respectively, with their associated water use efficiency increasing by 2.82% and 10.73% respectively.【Conclusion】Overall, high irrigation amount during fruit expansion stage coupled with a moderate irrigation amount during the fruit maturity stage can considerably improve water use efficiency, saving 2.50% to 11.62% of water, with only a slight compromise in yield, compared to the CK. It is therefore the most water-saving effective schedule to drip-irrigate the kiwi in the studied region.