东北薄层黑土区协调玉米产量和环境效应的氮肥一次性投入阈值

Input threshold of one-time application of nitrogen fertilizer to coordinate maize yield and environmental effects in thin layer black soil region of Northeast China

  • 摘要: 为探寻东北黑土区兼顾玉米产量与环境效应的氮肥一次性投入阈值, 在吉林省薄层黑土区(公主岭市刘房子村)开展了为期8年(2016—2023年)的田间定位试验, 研究氮肥(普通尿素与控释氮肥配施4:6)一次性施用条件下玉米产量、氮素吸收利用、土壤NO3-N含量变化和氮素平衡对不同氮肥用量(0、70、140、210、280和350 kg∙hm−2, 以N计)的响应。结果表明, 与不施氮肥处理相比, 施氮处理玉米产量8年平均增幅为63.8%~188.8%, 差异均达显著水平(P<0.05)。增产原因是施氮增加了穗粒数和百粒重。随氮肥用量增加, 玉米产量呈上升趋势, 当氮肥用量增加至 210 kg∙hm−2达到产量平台, 8年平均产量为11668 kg∙hm−2。氮素表观回收率、农学利用率和偏生产力均随氮肥用量增加呈下降趋势。随施氮年限和氮肥用量的增加, 0~100 cm土壤NO3-N含量呈增加趋势, 其中N210处理土壤NO3-N含量与试验起始值相近。8年氮素平衡结果显示, 氮素残留量与氮素损失量均随氮肥用量的增加呈增加趋势。通过拟合氮肥用量与玉米产量、土壤氮素损失量和氮素回收率的关系得出, 施氮范围在198~219 kg∙hm−2时, 可获得较高的玉米产量和氮肥利用率, 且能保持玉米收获前后土壤氮库的基本稳定, 同时也可将氮肥表观损失降至较低水平。因此可作为兼顾玉米产量和环境效益的氮肥一次性投入阈值。研究结果可为东北薄层黑土区玉米氮肥一次性施用提供理论依据。

     

    Abstract: To explore the input threshold of a one-time application of N fertilizer that considers maize yield and environmental effects in the black soil region of Northeast China, this study established an eight-year field experiment in the black thin-layer soil region of Jilin Province (Liufangzi village, Gongzhuling City) from 2016 to 2023. This study revealed the responses of maize yield, N uptake and utilization, soil NO3-N content, and soil N apparent balance to different nitrogen (N) fertilizer rates under the condition of a one-time application of N fertilizer (common urea plus controlled-release N fertilizer at a N ratio of 4∶6). Six N fertilizer application treatments were established: 0, 70, 140, 210, 280, and 350 kg∙hm−2, labeled as N0, N70, N140, N210, N280 and N350, respectively. The results showed that the eight-year average yield increased by 63.8%–188.8% under N fertilizer application treatments compared with no N fertilizer, and a significant difference was observed (P<0.05). The yield advantage under N fertilizer application treatments was mainly attributed to the increased grains per ear and 100-kernel weight of maize. The maize yield was an upward trend with increased N application rates, reaching the yield platform under 210 kg∙hm−2 of N fertilizer rates. With this N fertilizer rate, the average yield over eight years was 11 668 kg∙hm−2. The apparent N recovery efficiency (REN), N agronomic efficiency (AEN), and N partial factor productivity (PFPN) all declined with increasing N application rates. The NO3-N contents in the 0–100 cm soil layer increased with increasing N application years and N fertilizer rates. The NO3-N content in the N210 treatment was similar to the initial value of the experiment. In the eight-year experiment, the N balance results showed that N residuals and apparent N loss increased with increasing N fertilizer rates. The residual N in the N210 treatment was similar to the initial values in the experiment. When it reached the yield platform at 208.8 kg∙hm−2 of N fertilizer rate, maize yield, N recovery efficiency, soil N residuals, and N apparent loss were 11 835 kg∙hm−2, 48.2%, 172.3 kg∙hm−2 and 53.9 kg∙hm−2 respectively, by simulating between maize yield, N recovery efficiency, soil N residuals, N apparent loss, and N application rates, respectively. The calculated theoretical results for maize yield, N recovery efficiency, and N apparent loss matched well with the observed values under the maximum yield of the N210 treatment. Simultaneously, the residual N was similar to the initial value of the experiment. Within the 95% confidence interval of the N application rate under the theoretical maximum yield, the optimum N application rate was calculated at 198−219 kg∙hm−2. In conclusion, the N application range of 198−219 kg∙hm−2 obtained higher maize yield and N use efficiency, as well as maintained the basic stability of soil N pools before and after maize harvest, and also reduced N apparent loss to a lower level. Therefore, it can be used as an input threshold for the one-time application of N fertilizer that considers maize yield and environmental effects. These results provide a theoretical basis for the one-time application of N fertilizer to maize in the black, thin-layered soil region of Northeast China.

     

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