Nitrogen balance acts an indicator for estimating thresholds of nitrogen input in rice paddies of China

文献类型： 外文期刊

第一作者： Ding, Wencheng

作者： Ding, Wencheng;Xu, Xinpeng;Huang, Shaohui;He, Ping;Zhou, Wei;Zhang, Jiajia

作者机构：

关键词： Nitrogen threshold; Nitrogen surplus; Ammonia volatilization; Straw return; Rice

期刊名称：ENVIRONMENTAL POLLUTION （ 影响因子：8.071； 五年影响因子：8.35 ）

ISSN： 0269-7491

年卷期： 2021 年 290 卷

页码：

收录情况： SCI

摘要： Decision-making related to nitrogen (N) fertilization is a crucial step in agronomic practices because of its direct interactions with agronomic productivity and environmental risk. Here, we hypothesized that soil apparent N balance could be used as an indicator to determine the thresholds of N input through analyzing the responses of the yield and N loss to N balance. Based on the observations from 951 field experiments conducted in rice (Oryza sativa L.) cropping systems of China, we established the relationships between N balance and ammonia (NH3) volatilization, yield increase ratio, and N application rate, respectively. Dramatical increase of NH3 volatilizations and stagnant increase of the rice yields were observed when the N surplus exceeded certain levels. Using a piecewise regression method, the seasonal upper limits of N surplus were determined as 44.3 and 90.9 kg N ha -Iunder straw-return and straw-removal scenarios, respectively, derived from the responses of NH3 volatilization, and were determined as 53.0-74.9 and 97.9-112.0 kg N ha(-1) under straw-return and straw-removal scenarios, respectively, derived from the maximum-yield consideration. Based on the upper limits of N surplus, the thresholds of N application rate suggested to be applied in single, middle-MLYR, middle-SW, early, and late rice types ranged 179.0-214.9 kg N ha(-1) in order to restrict the NH3 volatilization, and ranged 193.3-249.8 kg N ha(-1) in order to achieve the maximum yields. If rice straw was returned to fields, on average, the thresholds of N application rate could be theoretically decreased by 17.5 kg N ha(-1). This study provides a robust reference for restricting the N surplus and the synthetic fertilizer N input in rice fields, which will guide yield goals and environmental protection.

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