| 郎漫,李平,魏玮.温度对农田黑土氮初级转化速率的影响[J].农业环境科学学报,2021,40(4):815-822. |
| 温度对农田黑土氮初级转化速率的影响 |
| Effect of temperature on gross N transformation rates in cropland black soil |
| 投稿时间：2020-09-27 |
| DOI：10.11654/jaes.2020-1133 |
| 中文关键词: 温度 黑土 15N标记 氮初级转化速率 |
| 英文关键词: temperature black soil 15N trace gross N transformation rates |
| 基金项目:国家自然科学基金项目（41301345，41101284） |
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| 摘要点击次数: 1137 |
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| 中文摘要: |
| 为探讨不同温度下土壤氮素的供应、固持和消耗损失过程，从而为农田土壤合理施用氮肥提供科学依据，以黑龙江省农田黑土为对象开展室内培养试验（15、25、35℃，60% WHC），采用15N同位素成对标记技术（15NH4NO3和NH415NO3，15N标记丰度为5atom%，氮浓度为60 mg N·kg-1）及FLUAZ数值优化模型研究土壤氮初级矿化速率、初级固定速率和初级硝化速率对温度变化的响应。结果表明：在15~35℃范围内，土壤氮初级矿化速率随培养温度的增加显著增加，但25~35℃范围内的增幅小于15~25℃。在15~25℃范围内，土壤氮初级固定速率和初级硝化速率随培养温度的增加显著增加，而在25~35℃范围内土壤氮初级固定速率和初级硝化速率随培养温度的增加显著降低，但仍然显著高于15℃处理。15℃和25℃处理土壤氮初级矿化速率与初级固定速率比值（gm/gi）以及初级硝化速率与初级铵态氮固定速率比值（gn/ia）均稍大于1，两处理间没有显著差异，而35℃处理的gm/gi值和gn/ia值均远大于1。研究表明，温度在15~25℃范围内，土壤有机氮的矿化与固定过程耦联相对紧密，硝态氮累积及淋溶风险较小；而35℃高温条件下土壤有机氮矿化速率和硝化速率均显著大于铵态氮的生物固定速率，表明硝化作用是铵态氮的主要消耗过程，可能会增加硝态氮的累积、反硝化和淋溶风险。 |
| 英文摘要: |
| The processes of N supply, retention, consumption, and loss in cropland soil at different temperatures were explored to provide a scientific basis for the rational application of N fertilizer. A paired 15N tracing incubation trial(15NH4NO3, NH415NO3, 15N isotopic excess of 5 atom%, and N concentration of 60 mg N·kg-1) combined with a numerical FLUAZ model was conducted to investigate the responses of the gross N mineralization rate, gross N immobilization rate, and gross nitrification rate in a cropland black soil in Heilongjiang Province, China to temperature changes(15, 25, and 35℃) at 60% water holding capacity. The results showed that the gross N mineralization rates increased significantly as the temperature increased in the range of 15~35℃, but the increase in amplitude in the range of 25~35℃ was smaller than that in the range of 15~25℃. In the range of 15~25℃, the gross N immobilization and nitrification rates increased significantly as the temperature increased, whereas these two rates decreased significantly as the temperature increased in the range of 25~35℃, but were still higher than those of the 15℃ treatment. The ratios of the gross N mineralization rate to immobilization rate(gm/gi) and gross nitrification rate to ammonium immobilization rate(gn/ia) were slightly higher than 1 at 15℃ and 25℃, respectively, and there was no significant difference between the two treatments, whereas these two ratios were both significantly higher than 1 at 35℃. The results indicated that the processes of N mineralization and immobilization were coupled relatively tightly at temperatures ranging from 15℃ to 25℃, and the risks of nitrate accumulation and leaching were lower. The mineralization rate of organic N and the nitrification rate significantly exceeded the ammonium immobilization rate after the temperature increased to 35℃, and nitrification was the dominant pathway of ammonium consumption in the soil, thereby increasing the potential risks of nitrate accumulation, denitrification, and leaching. |
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