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 kg(N)∙hm−2、70 kg(N)∙hm−2 、140 kg(N)∙hm−2、210 kg(N)∙hm−2、280 kg(N)∙hm−2和350 kg(N)∙hm−2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: In order to explore the input threshold of one-time application of N fertilizer that takes into account maize yield and environmental effects in the black soil region of Northeast China, this study sets up an eight-year located field experiment in 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 one-time application of N fertilizer (common urea plus controlled-release N fertilizer in N ratio of 4:6). Six N fertilizer application treatments were designed, including 0 kg∙hm−2, 70 kg∙hm−2, 140 kg∙hm−2, 210 kg∙hm−2, 280 kg∙hm−2 and 350 kg∙hm−2 (recorded as N0, N70, N140, N210, N280 and N350, respectively). The results showed that the eight-year average yield was increased by 63.8%~188.8% under N fertilizer application treatments than no N fertilizer, and there was significant difference (P<0.05). The yield advantage under N fertilizer application treatments was mainly attributed to increased grains per ear and 100-kernel weight of maize. The maize yield was an upward trend with the increase of N application rates, which it reached the yield platform under 210 kg∙hm−2 of N fertilizer rates. Under this N fertilizer rate, the average yield was 11668 kg∙hm−2 across eight years. The apparent N recovery efficiency (REN), N agronomic efficiency (AEN), and N partial factor productivity (PFPN) all declined with the increase of N application rates. NO3--N contents in 0-100 cm soil layer increased with increase of N application years and N fertilizer rates. Among them, the NO3--N content in N210 treatment was similar to the initial value of the experiment. In the eight-year experiment, N balance results showed that the N residuals and N apparent loss increased with the increase of N fertilizer rates. Among them, the N residuals in N210 treatment was similar to the initial value of the experiment. When it reached the yield platform under 208.8 kg∙hm−2 of N fertilizer rate, maize yield, N recovery efficiency, soil N residuals and N apparent loss were 11835 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 of the maize yield, N recovery efficiency and N apparent loss matched well with the observed values under the maximum yield of N210 treatment. At the same time, the N residual was similar to the initial value of the experiment. Within the 95% confidence interval of N application rate under the theoretical maximum yield, the optimum N application rate was calculated at the range of 198−219 kg∙hm−2. In conclusion, the N application range of 198−219 kg∙hm−2 not only obtained higher maize yield and N use efficiency, but also 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 input threshold of one-time application of N fertilizer that takes into account maize yield and environmental effects. This research results can provide a theoretical basis for one-time application of N fertilizer of maize in black thin-layer soil region of Northeast China.

     

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