绿洲灌区密植对氮肥减量玉米产量的补偿潜力OA北大核心CSTPCD

[Objective]To address the issue of excessive nitrogen fertilizer use for maize production in an oasis irrigation area,this study investigated the compensation effect for nitrogen fertilizer reduction through dense planting on maize yield.[Method]From 2019 to 2021,a two-factor split-plot experiment was carried out to explore the effect of different maize densities on yield and yield components under nitrogen reduction conditions.The main plot was two nitrogen application rate,including 25%reduction(N1,270 kg·hm-2)and local habitual nitrogen application(N2,360 kg·hm-2),and sub-plot was three planting densities of maize,including traditional(M1,78 000 plants/hm2),medium(M2,104 000 plants/hm2,33%increase),and high planting density(M3,129 000 plants/hm2,66%increase).[Result](1)The grain yield and biomass of maize under N1 decreased by 4.0%and 4.9%than that under N2 respectively due to nitrogen reduction,which could be compensated by dense planting.The grain yield of N1M2 was increased by 4.1%compared with that of the control treatment(N2M1),while the biomass of treatment of high density and nitrogen reduction(N1M3)had the largest compensation effect,which was increased by 14.2%compared with that under the control.(2)According to the regression analysis,at the N1 level,the density of 84 000 plants/hm2 could get the equal grain yield of the control treatment,and reached the maximum grain yield of 13 537 kg·hm-2 at 106 000 plants/hm2,achieving a 4.9%increase in grain yield.(3)Compared with N2,N1 reduced maize ear number,kernel number per ear,and 1 000-kernel weight by 5.0%,3.3%,and 3.4%,respectively,but had no significant effect on the harvest index.M2 and M3 increased the maize ear number by 27.9%and 49.7%,reduced kernel number per ear by 3.8%and 8.4%,respectively,and decreased 1 000-kernel weight by 5.2%and 8.9%,respectively.M2 had no significant effect on the harvest index,while M3 significantly reduced the harvest index by 14.2%.Therefore,compared with N2M1,N1M2 compensated for the decrease in ear number,kernel number per ear,and 1 000-kernel caused by nitrogen reduction through the increase of ear number.(4)N1 decreased the maize growth rate from the jointing stage to the tasseling and silking stage by 7.2%-8.4%,while M2 and M3 significantly increased the maize growth rate by 27.3%and 60.3%compared with traditional density from the seedling stage to the trumpet stage.(5)Compared with N2M1,N1M2 increased maize leaf,stem,and sheath dry matter transportation amount(DTA)by 9.6%,13.6%,and 3.7%,respectively,and the contribution rate of vegetative organs to grain(GCR)by 5.3%and 9.0%,respectively.[Conclusion]In the oasis irrigation area,the maize grain yield decrease caused by nitrogen reduction could be compensated by reasonably dense planting.Increasing the density to 104 000 plants/hm2 based on 25%nitrogen reduction could maximize the yield compensation effect,which was a feasible measure to save nitrogen for a stable and high yield of maize.