Nitrogen runoff dominates water nitrogen pollution from rice-wheat rotation in the Taihu Lake region of China
Nitrogen runoff dominates water nitrogen pollution from rice-wheat rotation in the Taihu Lake region of China
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DOI：
10.1016/j.agee.2012.04.024
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发表时间：
2012-08
期刊：
影响因子：
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通讯作者：
Xu Zhao;Yangxue Zhou;J. Min;Shenqiang Wang;W. Shi;G. Xing
中科院分区：
文献类型：
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作者：
Xu Zhao;Yangxue Zhou;J. Min;Shenqiang Wang;W. Shi;G. Xing
氮（N）径流和淋溶是氮污染从农田到水系统的两个直接途径。集约化稻麦轮作制度是否导致太湖地区周边水系氮污染尚无定论。我们进行了为期三年的田间试验来监测稻麦土壤中的氮径流和淋溶。年氮径流和淋失量范围为 55.3–93.1kgNha−1，平均值约为69.2kgNha−1。在向水系统输出的总氮中，82-93% 来自氮径流，只有 7-18% 来自氮淋溶。从季节分布来看，麦季贡献了总氮的57%~85%，稻季贡献了15%~43%。由于不同的用水方式，两个作物季节的氮径流和淋溶表现出完全不同的模式。麦季氮径流较多，主要是由于中强降雨和现有排水沟水流加快所致。稻季氮径流的巨大变化主要是由于自然降水的变化和不规则的人工排水。麦季氮淋失似乎与施肥和降水有关，而稻季则与施肥和土壤深度有关。这些实地数据表明，在常规氮和水管理下，径流主导了稻麦轮作的氮输出，可能导致 TLR 的水污染。
Nitrogen (N) runoff and leaching are two direct pathways of N pollution from agricultural land to water systems. It is not yet conclusive whether intensive rice-wheat rotation system contributes to N pollution in the surrounding water systems in the Taihu Lake region (TLR). We conducted a three-year field experiments to monitor N runoff and leaching from rice-wheat paddy soil. Annual N runoff and leaching was in the range of 55.3–93.1kgNha−1, with a mean of ca. 69.2kgNha−1. Of the total N export to water systems, 82–93% was from N runoff and only 7–18% was from N leaching. For seasonal distribution, the wheat season contributed 57–85% of total N, while the rice season contributed 15–43%. Because of different water practices, N runoff and leaching exhibited completely different patterns in two crop seasons. Considerable N runoff in wheat season can mainly be attributed to moderately heavy rainfall and accelerated water flow in existing drainage ditches. Large variations in N runoff during rice season were predominantly due to variable natural precipitation and irregular artificial draining. N leaching appeared to be related to fertilization and precipitation in wheat season, while it was associated with fertilization and soil depth during rice season. These field data suggest that runoff dominated N export from rice-wheat rotation under conventional N and water management contributes potentially to water pollution in the TLR.