不同秸秆与氮肥管理措施对夏玉米产量及氮素利用的影响

为探讨不同秸秆还田模式下，氮肥管理对夏玉米产量和氮素利用的影响，试验设置施氮措施和秸秆还田模式2个因素。施氮措施设稳定性氮肥施氮量F1（180 kg·hm^-2）、尿素减量施氮量F2（180 kg·hm^-2）和尿素农户传统施氮量F3（270 kg·hm^-2）3个水平；秸秆还田模式设秸秆不还田（N）和秸秆还田（S）2个水平，共6个处理。结果表明：在不同秸秆还田模式下，各施氮措施的玉米产量在8 708.16~9 626.71 kg·hm^-2之间，处理间无显著性差异（P>0.05）。在不同施氮措施下，秸秆还田（S）的产量均高于秸秆不还田（N），增幅为4.96%~8.94%（P>0.05）。施氮措施对土壤N₂O排放量有显著影响（P<0.05），在不同秸秆还田模式下，稳定性氮肥措施F1和尿素减量措施F2的土壤N₂O排放量显著低于F3尿素农户施氮措施，降幅为29.26%~68.52%，且F1和F2之间存在显著差异（P<0.05）。在不同施氮措施下，除了SF2和NF2处理之间的N₂O排放量有显著性差异(1.53 kg·hm^-2和1.91 kg·hm^-2)，其他秸秆还田模式处理之间均无显著性差异（P>0.05）。不同秸秆还田模式下，各施氮措施的氨挥发累积量在1.61~15.40 kg·hm^-2之间，表现为：F3氨挥发累积量最高（14.37 kg·hm^-2和15.40 kg·hm^-2），F2氨挥发累积量次之（11.80 kg·hm^-2和12.49 kg·hm^-2），F1氨挥发累积量最低（1.61 kg·hm^-2和1.79 kg·hm^-2），各施氮措施间达到显著水平（P<0.05）。在不同施氮措施下，秸秆还田（S）的氨挥发累积量较秸秆不还田（N）提高5.85%~11.18%，但除了SF3和NF3的氨排放量有显著性差异，其他处理间均无显著性差异。不同秸秆还田模式下，各施氮措施0~100 cm土层硝态氮含量均表现出F3>F2>F1；秸秆还田处理（SF1、SF2和SF3）的土壤硝态氮含量显著低于无秸秆还田（NF1、NF2和NF3），分别显著降低了65.65%、144.79%和128.48%。因此，综合考虑作物产量和农田氮素损失，秸秆还田+稳定性氮肥处理（SF1）是本研究地区夏玉米稳产减排的最优试验处理组合。

Effects of different straw and nitrogen fertilizer management measures on summer maize yield and nitrogen utilization

In order to investigate the effects of nitrogen fertilizer management on summer maize yield and nitrogen utilization under different straw returning modes, the field experiment including two factors of nitrogen application measures and straw returning modes were created. Three nitrogen application measures were stable nitrogen fertilizer application rate F1(180 kg·hm^-2), urea reduction nitrogen application rate F2(180 kg·hm^-2), and farmer urea traditional nitrogen application rate F3(270 kg·hm^-2). The 2 levels of straw returning modes were straw not returned to the field (N) and straw returned to the field (S). There were 6 treatments were established. The results showed that the maize yield of each nitrogen application measure ranged from 8 708.16 kg·hm^-2 to 9 626.71 kg·hm^-2 under different straw returning modes, and there was no significant difference found between the treatments (P>0.05). Under different nitrogen application measures, the yield of straw returned to the field (S) was higher than that of straw not returned to the field (N), with an increase of 4.96%~8.94% (P>0.05). Nitrogen application measure had a significant impact on soil N₂O emissions (P<0.05). Under different straw returning modes, the soil N₂O emissions of stable nitrogen fertilizer measure F1 and urea reduction measure F2 were significantly lower than that of farmer urea traditional nitrogen application F3 urea farmers by 29.26%~68.52%, and there was a significant difference between F1 and F2 (P<0.05). Under different nitrogen application measures, except for the significant difference in N₂O emissions from SF2 and NF2 (1.53 kg·hm^-2 and 1.91 kg·hm^-2), there was no significant difference between other straw returning treatments (P>0.05). Under different straw returning modes, the cumulative amount of ammonia volatilization of each nitrogen application measure ranged from 1.61 kg·hm^-2 to 15.40 kg·hm^-2. The cumulative amount of ammonia volatilization of F3 was the highest (14.37 kg·hm^-2 and 15.40 kg·hm^-2), followed by that of F2 (11.80 kg·hm^-2 and 12.49 kg·hm^-2), and that of F1 was the lowest (1.61 kg·hm^-2 and 1.79 kg·hm^-2), which reached a significant level among the various nitrogen application measures (P<0.05). Under different nitrogen application measures, the cumulative amount of ammonia volatilization of straw returned to the field (S) was 5.85%~11.18% higher than that of straw not returned to the field (N), but there was no significant difference except for the significant difference between SF3 and NF3. Under different straw returning modes, the NO^-₃-N content of the 0~100 cm soil layer of each nitrogen application measure showed F3>F2>F1. The soil NO^-₃-N content of the straw returned to the field treatments (SF1, SF2 and SF3) was significantly lower than that of straw not returned to the field (NF1, NF2 and NF3), significantly reduced by 65.65%, 144.79% and 128.48%, respectively. Therefore, considering crop yield and nitrogen loss in farmland comprehensively, the treatment of straw returning + stable nitrogen fertilizer (SF1) was the best experimental treatment combination for stable production and emission reduction of summer maize in this study area.