Precipitation increase enhanced the positive effect of nitrogen addition on soil N2O emissions by promoting soil nitrogen transformation and plant productivity in saline-alkaline grassland of Northern China

Huajie Diao, Wenli Xu, Jingjing Wang, Wenjun Liang, Yangyang Gao, Gaoliang Pang, Yicong Chen, Jianyu Wang, Yuxin Huang, Jie Hao, Changhui Wang, Xiang Zhao and Kuanhu Dong

Agricultural Water Management, 2025, vol. 314, issue C

Abstract: Individual effects of continued increases in nitrogen (N) deposition and changes in precipitation have been reported to have profound effects on N cycling in grassland ecosystems. However, the response and regulatory mechanisms of soil nitrous oxide (N2O) flux to N deposition under conditions of changing precipitation are still unclear, especially in saline-alkaline grasslands. A 3-yr (2021–2023) manipulative field experiment was carried out to investigate the effects of N addition and precipitation changes ( ± 50 % in ambient precipitation) in a saline-alkaline grassland of the agro-pastoral ecotone in Northern China. The results indicate that: (1) compared with the results of the control plots, N addition alone significantly increased soil N2O flux by 107.0 %; changes in precipitation alone showed no significant effect on soil N2O flux; and N addition combined with increased precipitation yielded a significant increase of 180.1 % in soil N2O flux across the three years. (2) The positive effect of N addition on soil N2O flux was increase exponentially with increasing precipitation. (3) N addition, rather than a change in precipitation, significantly increased the seasonal mean net nitrification rate (Rnit) by 191.8 %, the net N mineralization rates (Rmin) by 181.7 %, and the gene abundance of ammonia-oxidising archaea (AOA) by 3 %. (4) Soil N2O flux was significantly and positively correlated with above-ground primary productivity (ANPP), Rnit, and Rmin; and the relative changes in soil N2O flux and plants productivity induced by N addition were all increased with precipitation. (5) Plants characteristics and soil microbial N mineralization indirectly regulated the effects of N addition and precipitation alteration on soil N2O flux. These observations highlight that increased precipitation can enhance the soil N2O emissions under concurrent N deposition scenarios, and thus exacerbate global warming. This study provided a theoretical basis for the restoration and utilization of degraded grasslands in agro-pastoral ecotone grassland in Northern China.

Keywords: Soil N2O flux; Extreme drought; N deposition; Saline-alkaline grassland (search for similar items in EconPapers)
Date: 2025
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Persistent link: https://EconPapers.repec.org/RePEc:eee:agiwat:v:314:y:2025:i:c:s0378377425002239

DOI: 10.1016/j.agwat.2025.109509

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