减氮对引黄灌区春玉米氮素吸收利用和淋失的影响OA北大核心CSTPCD

The study aimed to investigate yield characteristics,nitrogen uptake,and leaching losses of spring maize under different levels of nitrogen reduction and to provide a theoretical basis for the reasonable application of nitrogen fertilizer to spring maize in the Ningxia Yellow River irrigation area.A field experiment was conducted for two consecutive years from 2021 to 2022 in the Ningxia diversion irrigation district.The experiment used Centaur 1225 as the maize test variety in a seepage pond.Five nitrogen levels with nitrogen applications of 420 kg·hm-2(N-420),14.29%(N-360),35.71%(N-270),57.14%(N-180)N reduction,and no N application treatments(CK),were included in the study.The yield,nitrogen uptake and utilization,and N leaching losses of spring maize were measured and analyzed.No significant difference(P<0.05)was observed in crop yield between crops grown under conventional fertilizer application and those grown under 14.29%N reduction treatment.A reduction in yield was observed under 35.71%N reduction treatment compared with conventional fertilizer treatment.Compared with the conventional fertilizer application treatment,35.71%N reduction and 14.29%N reduction treatments reduced grain yield in 2021 by only 8.60%and 3.59%,respectively.In 2022,35.71%N reduction reduced grain yield by 11.46%whereas 14.29%N reduction treatment increased the seed yield by 1.42%compared with the conventional fertilizer treatment.The utilization and agronomic efficiency of N fertilizer and the above-ground nitrogen harvest index data for both years showed that they were higher for the 35.71%N reduction treatment than the 14.29%N reduction and the conventional fertilizer treatments.Moreover,the N fertilizer bias productivity gradually decreased with increasing N application.Compared with the bias productivity of 57.14%N reduction treatment,the corresponding values for 35.71%N reduction,14.29%N reduction,and conventional fertilizer treatments decreased by 19.57%,33.81%,and 42.59%,respectively.The apparent leaching coefficient of nitrogen fertilizer increased with the increase of nitrogen application,and the total nitrogen leaching losses were reduced by 42.51%and 18.09%in the 35.71%and 14.29%N reduction treatments,respectively,compared with the losses in the conventional nitrogen application treatment.Under each treatment,nitrate-nitrogen was the main form of nitrogen leaching,accounting for 45.50%-54.68%of the total leached nitrogen.Correlation analysis between nitrogen application and total nitrogen leaching losses showed that they were positively correlated,and the total nitrogen leaching losses increased exponentially(R2=0.998 6)with the increase of nitrogen application.Compared with conventional N application,a 35.71%reduction in N application reduced spring maize yield by 10.03%and N leaching by 42.51%,which improved the agronomic efficiency and biased productivity of N fertilizer.Hence,N application of 270 kg·hm-2 can be a reasonable choice to reconcile the yield and environmental safety of spring maize in the Yellow River irrigation area.