隔沟调亏灌溉对冬小麦-夏玉米光合特性和产量的影响

Improving Photosynthesis and Water Use Efficiency of Winter Wheat and Summer Maize by Coupling Alternate Furrow Irrigation and Regulated Water Deficit

【目的】了解垄栽模式下隔沟调亏灌溉对冬小麦-夏玉米光合特性和产量的影响及其机理。【方法】在移动式防雨棚下测坑内进行试验,设置3种灌溉方式,即常规畦灌、隔沟交替灌溉、隔沟调亏灌溉,分别在冬小麦返青—拔节期、拔节—抽穗期、抽穗—灌浆期以及夏玉米苗期—拔节期、拔节—抽雄期、抽雄—灌浆期进行水分调控,冬小麦和夏玉米各有5个处理,并测定了作物各生育期净光合速率、蒸腾速率、产量和WUE等指标。【结果】冬小麦返青期和夏玉米苗期隔沟调亏灌溉处理虽然在调亏时期内降低了光合作用,但复水后的光合补偿效应有利于实现稳产。冬小麦、夏玉米试验各处理产量顺序均为:T1处理>T2处理>T3处理>T4处理>T5处理,常规地面灌仍然能够保证作物的最高产量,但WUE却大幅降低。冬小麦试验中,与T1处理相比,T2、T3处理分别减产1.98%(p>0.05)和5.68%(p<0.05),但分别节水10.01%(p<0.01)和16.91%(p<0.01),水分利用效率分别提高9.04%(p<0.05)和15.82%(p<0.01)。夏玉米试验中,T2、T3处理的产量分别较T1处理降低2.93%(p>0.05)和6.21%(p<0.05),但分别节水12.40%(p<0.01)和20.59%(p<0.01),WUE分别提高10.06%(p<0.01)和17.32%(p<0.01)。【结论】在保证底墒充足的情况下,冬小麦、夏玉米采取隔沟调亏灌溉是可行的,冬小麦返青—拔节期适度水分胁迫(55%FC～65%FC)和夏玉米苗期—拔节期的适度水分胁迫(60%FC～70%FC),能够保证作物在不大幅减产的情况下,具有最高的水分利用效率。

[Objective] Improving irrigation efficiency plays a key role in developing sustainable agriculture and the purpose of this paper was to investigate the effects of alternate furrow irrigation with regulated water deficit on photosynthesis and yields of rotated winter wheat and summer maize. [Method] Experiments were conducted in lysimeters under a rainproof shelter in 2016-2017 with three treatments： conventional border irrigation （T1）, standard alternate furrow irrigation （T2）, and alternate furrow irrigation with regulated water deficit （T3）. During the experiments, the photosynthesis, water use efficiency （WUE） and the yields of the wheat and the maize were measured at different growth stages. [Result]The net photosynthetic rate and the transpiration rate of the two crops under T1 were higher than that under T3, but re-watering after water stress could compensate the lost photosynthesis, thereby maintaining yields. The yields of the two crops under T1 was higher than those T2 and T3, but its water use efficiency was low. Compared to T1, T2 and T3 reduced the wheat yield by 1.98% （p〉0.05） and 5.68% （p〈0.05）, while reduced water consumptions by 10.01% （p〈0.01） and 16.91% （p〈0.01） with their associated WUE increasing by 9.04% （p〈0.05） and 15.82% （p〈0.01） respectively. Similarly, compared to T1, T2 and T3 reduced the maize yield by 2.93% （/7〉0.05） and 6.21% （p〈0.05） respectively, but increased the WUE by 10.06% （p〈0.05） and 17.32% （p〈0.01） respectively. [Conclusion] Alternate furrow irrigation by imposing a water deficit of 55%-65% of field moisture capacity at the returning green stage of the winter and a water deficit of 60%- 70% of field moisture capacity at the seedling stage of summer maize can substantially improve WUE without considerably scarifying their yields.