Optimization of irrigation quota and scheduling for drip-irrigated spring maize in plastic-mulched fields of Northwestern China

Wang Lingxiang; Liu Liping; Wang Xiaoxuan; Zhang Liuyulei; Yang Shengju; Tong Ling

doi:10.13522/j.cnki.ggps.2026017

Abstract：[Objective]Spring maize production in arid northwest China relies heavily on irrigation.Irrigation amount and scheduling thus exert considerable impacts on crop growth and yield.Using a crop model,this paper models the effects of drip irrigation scheduling on growth and yield of spring maize in plastic-mulched fields in the region.[Method]The modelling was based on field data collected during the 2020-2021 growing seasons.These data were used to calibrate and validate the AquaCrop model first,and the validated model was then used to simulate the responses of maize growth and yield(Y)to different irrigation scenarios.We set 10 irrigation quotas ranging from 300 to 740 mm(W1-W10),and three irrigation modes that prioritized water supply at the jointing stage(I1),tasseling stage(I2),or grain-filling stage(I3).The simulations covered three precipitation year types:wet year(N1),normal year(N2)and dry year(N3).[Result]The AquaCrop model satisfactorily reproduced the crop growth and yield dynamics;its normalized root mean square error(NRMSE)for canopy cover(CC)and aboveground biomass(B)was≤9.33%,while the index of agreement(d)and coefficient of determination(R2)were both≥0.98.The relative errors between simulated and measured maize yield ranged from 3.76%to 7.08%.Simulation results showed that irrigation quota,irrigation allocation prioritization,and precipitation year type all significantly affected maize yield and irrigation water productivity.Under the same irrigation quota,prioritizing irrigation at the tasseling stage produced significantly higher yield than at the jointing stage(I1)and grain-filling stage(I3).With increasing irrigation quota,maize yield varied quadratically:rising first and then declining,while irrigation water productivity decreased monotonically.[Conclusion]Considering both maize yield and irrigation water productivity,the optimal irrigation quota was 400、440 mm and 480 mm for wet,normal and dry year,respectively,with irrigation water preferentially applied during the tasselling stage.This irrigation scheduling can be used for drip-irrigated spring maize production in plastic-mulched fields in arid regions in Northwestern China.