滴灌水钾耦合对不同生育期猕猴桃光合特性、生长及产量的影响OA

To provide a scientific basis for formulating rational water and potassium management strategies in kiwifruit orchards,this study investigated the effects of different drip irrigation water-potassium coupling treatments on the growth,development and fruit volume of'Jinyan'kiwifruit under drip-fertigation.Two water-deficit levels(low water,LW;and high water,HW,applied at 60%and 80%of the control[CK],respectively)and three potassium-deficit levels(low potassium,LK;medium potassium,MK;and high potassium,HK,applied at 40%,60%,and 80%of CK,respectively)were applied during the flowering-fruit set,fruit swelling,and fruit maturation stages.The results showed that the net photosynthetic rate(Pn)was highest in the CK treatment at the pre-midday peak during flowering-fruit set[9.95 μmol/(m²·s)],while the high-water-high-potassium(HWHK)treatment increased the post-midday peakby 15.27%compared with CK.The CK treatment performed best during fruit swelling.During fruit maturation,the high-water-medium-potassium(HWMK)treatment significantly raised the afternoon Pn peak by 44.82%over CK.The intrinsic water-use efficiency(WUE ₙ)during flowering-fruit set increased by 4.40%～122.01%in all treatments relative to CK,and the HWHK treatment elevated the morning-peak WUEₙ by 15.22%in the fruit-swelling stage.Shoot growth rates during flowering-fruit set were 17.98%～25.83%lower in all treatments than in CK.After entering the fruit-swelling stage,compensatory growth occurred in the HWLK and HWMK treatments,with shoot growth rates increasing by 4.24%～7.70%compared with CK.The HWHK treatment enhanced the growth rate by 39.38%during fruit swelling and by 31.46%during fruit maturation relative to CK.The mean leaf area index(LAI)over the whole growth period ranged from 2.30 to 2.69 for all water-potassium deficit treatments,showing a declining trend compared with the CK value of 2.70.The HWHK treatment exhibited the smallest reduction,decreasing by only 0.65%～2.53%.In terms of fruit volume,during the rapid growth period of fruit maturity,the volume growth rate of HWHK treatment and HWMK treatment were significantly higher than that of CK.In terms of yield,HWMK during the flowering and fruit-setting period and the fruit ripening period performed best,while HWHK during the fruit expansion period performed best.Therefore,it is recommended to apply the HWMK treatment during the flowering-fruit set and fruit maturation stages,and the HWHK treatment during the fruit expansion stage.This approach can reduce water and potassium inputs and improve resource-use efficiency without affecting tree growth or fruit formation.