Unimodal Response of Soil Methane Consumption to Increasing Nitrogen Additions
作 者：Peng YF, Wang GQ, Li F, Yang GB, Fang K, Liu L, Qin SQ, Zhang DY, Zhou GY, Fang HJ, Liu XJ, Liu CY, Yang YH*
影响因子:6.653
刊物名称:Environmental Science & Technology
出版年份:2019
卷:53期:8 页码:4150-4160
文章摘要:Nitrogen (N) status has a great impact on methane (CH₄) consumption by soils. Modeling studies predicting soil CH₄consumption assume a linear relationship between CH₄uptake and N addition rate. Here, we present evidence that a nonlinear relationship may better characterize changes in soil CH₄uptake with increasing N additions. By conducting a field experiment with eight N-input levels in a Tibetan alpine steppe, we observed a unimodal relationship; CH₄uptake increased at low to medium N levels but declined at high N levels. Environmental and microbial properties jointly determined this response pattern. The generality of the unimodal trend was further validated by two independent analyses: (i) we examined soil CH₄uptake across at least five N-input levels in upland ecosystems across China. A unimodal CH₄uptake-N addition rate relationship was observed in 3 out of 4 cases; and (ii) we performed a meta-analysis to explore the N-induced changes in soil CH₄uptake with increasing N additions across global upland ecosystems. Results showed that the changes in CH₄uptake exhibited a quadratic correlation with N addition rate. Overall, we suggest that the unimodal relationship should be considered in biogeochemistry models for accurately predicting soil CH₄consumption under global N enrichment.