The Responses of Soil Nitrogen Transformations to Rainfall Reduction Mainly Occurred in the Early Growing‐Season in a Temperate Meadow

作者：Xuechen Yang, Marcelo Sternberg, Wenzheng Song, Shangzhi Zhong, Hua Chai, Junqin Li, Yuan Yao, Bo Meng, Mengyang You, Qi Jiang, Xiuquan Yue, Lu‐Jun Li, Jianying Ma, Wei Sun · 发表于：Journal of Geophysical Research Biogeosciences · 年份：2024 · DOI：10.1029/2023jg007749 · 被引用次数：2 · 研究领域：Soil Carbon and Nitrogen Dynamics、Peatlands and Wetlands Ecology、Soil and Water Nutrient Dynamics

Abstract Drought is expected to increase in temperate regions in the coming decades due to global climate change and will strongly affect nitrogen ( N ) transformation and balance. However, the underlying mechanisms (soil microenvironment vs. biotic community) of rainfall reduction induced changes in soil N transformation rates, and whether the responses of soil N transformation rates to rainfall reduction vary over time remains poorly understood. In this study, we experimentally examined rainfall reduction effects on soil N transformation rates over two (the second and third experimental years) growing‐seasons in a temperate meadow. We applied four treatments: ambient rainfall, 30%, 50%, and 70% reduction in rainfall. Our findings demonstrated that, 70% rainfall reduction significantly decreased the average net N mineralization and nitrification rates by 68.4% and 72.0%, respectively. Soil nitrous oxide emission was profoundly varied between the experimental years, with it was sensitive no only to changes in annual precipitation amount, but also to seasonal distribution, the highest emissions appeared at the early growing‐season. Moreover, plant diversity, microbial biomass, and soil NO 3 − ‐N content mainly regulated soil N transformation rates in response to rainfall reduction in the greater annual precipitation year; but soil N transformation rates were mainly controlled by soil water content in the less annual precipitation year. We suggest that to accurately project fut...