Non-linear responses of the plant phosphorus pool and soil available phosphorus to short-term nitrogen addition in an alpine meadow

作者：Bing Han, Yicheng He, Jun Zhou, Yufei Wang, Lina Shi, Zhenrong Lin, Lu Yu, Wantong Zhang, Yiyi Geng, Xinqing Shao · 发表于：Journal of Integrative Agriculture · 年份：2024 · DOI：10.1016/j.jia.2024.07.033 · 被引用次数：6 · 研究领域：Soil Carbon and Nitrogen Dynamics、Soil and Water Nutrient Dynamics、Plant nutrient uptake and metabolism

Nitrogen (N) enrichment is expected to induce a greater phosphorus (P) limitation, despite the acceleration of soil P cycling. However, the changing patterns in plant P and soil available P after N enrichment, and their regulatory mechanisms, remain poorly understood in alpine meadows. Here, we conducted a field experiment with four N addition rates (0, 5, 10, and 15 g N m-2 yr-1) in an alpine meadow, and investigated the P in plants, microorganisms, and soil to determine their patterns of change after short-term N addition. Our results showed that N addition significantly increased plant biomass, and the plant P pool showed a non-linear response to the N addition gradient. Soil available P initially increased and then declined with increasing N addition, whereas the occluded inorganic P decreased markedly. The critical factors for soil available P varied with different N addition rates. At lower N addition levels (0 and 5 g N m-2 yr-1), soil acidification facilitated the mobilization of occluded inorganic P to increase soil available P. Conversely, at higher N addition levels (10 and 15 g N m-2 yr-1), the elevated soil microbial biomass P intensified the competition with plants for soil P, leading to a decline in soil available P. This study highlights the non-linear responses of the plant P pool and soil available P concentration to N addition rates. These responses suggest the need for developing ecosystem models to assess different effects of increasing N rates, which wou...