| 氮肥分施次数及硝化抑制剂对盆栽玉米N2O排放的影响 |
| 摘要点击 1916 全文点击 595 投稿时间：2021-01-02 修订日期：2021-03-03 |
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| 中文关键词 施肥次数 玉米产量 氮利用效率 N2O排放 功能基因 |
| 英文关键词 fertilization times corn yield nitrogen efficiency N2O emission functional gene |
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| 中文摘要 |
| 合理施氮是获得较高目标产量和降低因氮环境污染的重要策略.通过盆栽试验研究等氮量下不同分施次数对玉米产量及土壤N2O排放的影响，并探讨氮转化功能基因丰度与N2O排放的关系.本试验设空白（CK，不施尿素）、一次性施氮（S1，将0.5g·kg-1尿素一次性施入土壤+硝化抑制剂）、二次分施（S2，将0.5g·kg-1尿素分40%和60%两次施入土壤）和三次分施（S3，将0.5g·kg-1尿素分20%、40%和40% 3次施入土壤）.结果表明：①施氮促进土壤酸化，氮分施次数造成土壤酸化程度的显著差异，氮分施次数越多，土壤酸化越强.施氮显著提高鲜食玉米果穗产量及茎秆生物量，但氮肥分施次数对土壤pH影响的差异可能会导致植物对氮的吸收利用程度也存在着差异.S3处理显著降低土壤pH的同时，也降低了植物氮吸收累积量和氮素利用效率，也造成了高的N2O累积排放量.与S3处理相比，S1和S2处理分别增产了40.21%和42.55%，其N2O累积排放量也分别显著降低了79.4%和20.9%.② N2O排放与AOB和nirK基因丰度呈显著正相关关系，AOB和nirK是N2O排放的主要贡献者.S1处理显著降低了AOB和nirK基因丰度，降低N2O排放，S2和S3处理施肥后显著增加了nirK和nirS基因丰度，降低了nosZ基因丰度，促进了N2O的排放.氮分施次数影响氮转化过程的功能基因，从而影响N2O排放.由此可见，尿素配合DCD一次性施入不仅能保证玉米产量，提高氮素利用效率，还能降低温室气体排放，可作为海南地区鲜食玉米种植过程推荐的施肥模式. |
| 英文摘要 |
| Rational application of nitrogen is an important strategy for increasing yield while reducing environmental pollution due to nitrogen. Pot experiments were conducted to study the effects of different application times on maize yield and soil N2O emission under conditions of equal nitrogen content, and to explore the relationship between the abundance of nitrogen conversion functional genes and N2O emission. Four treatments were used, namely a control (CK, no urea), one-time application (S1, one application of 0.5 g·kg-1 urea+nitrification inhibitor), two separate applications ［S2, two applications of 0.5 g·kg-1 urea (40% and 60% respectively)］ and three separate applications (S3, 0.5 g·kg-1 urea was divided into three different applications: 20%, 40% and 40% respectively). The results showed that: ① nitrogen application promoted soil acidification, and the degree of soil acidification varied significantly with different application times. More applications of nitrogen led to stronger soil acidification. Nitrogen application significantly increased the ear yield and stem biomass of fresh table maize, but different nitrogen application times may alter soil pH, leading to differences in the degree of nitrogen uptake and utilization in plants. While the S3 treatment significantly reduced soil pH, it also reduced the cumulative nitrogen uptake and utilization in the plants, resulting in a high cumulative N2O emission. Compared with the S3 treatment, the yield was 40.21% and 42.55% higher in the S1 and S2 treatments, and the cumulative N2O emission decreased by 79.4% and 20.9%, respectively. ② N2O emission was positively correlated with the abundance of AOB and nirK genes, which were the main contributors to N2O emission. S1 significantly decreased the abundance of AOB and nirK genes and N2O emissions, while S2 and S3 significantly increased the abundance of nirK and nirS genes and decreased the abundance of nosZ genes after fertilization, promoting N2O emissions. Nitrogen application times affect the functional genes of the nitrogen transformation process, and thus affect N2O emissions. In conclusion, a one-time application of urea combined with DCD only guarantees high maize yield and improves the efficient use of nitrogen, but also reduces greenhouse gas emissions. Thus, it is the recommended nitrogen fertilization mode for the cultivation of fresh corn in Hainan. |
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