Grazing intensity shifts plant-microbe competition for ammonium and nitrate in temperate grasslands
文献类型：期刊论文
| 作者 | Iqbal, Majid4,5; Liu, Min4,5; Tian, Yuqiang2,3; Jin, Peng4,5; Yu, Chengling4,5; Ding, Yong1; Xu, Xingliang4,5 |
| 刊名 | JOURNAL OF ECOLOGY
 |
| 出版日期 | 2026-03-11 |
| 卷号 | 114期号:3页码:e70285 |
| 关键词 | 15N labelling N retention nitrogen competition plant-soil interactions temperate grassland |
| ISSN号 | 0022-0477 |
| DOI | 10.1111/1365-2745.70285 |
| 产权排序 | 1 |
| 文献子类 | Article |
| 英文摘要 | In temperate grasslands, competition between plants and soil microbes for inorganic nitrogen (N) is a critical process in regulating N retention, loss and overall ecosystem productivity. However, how grazing intensity alters this competition, particularly for specific N forms such as ammonium (NH4+) and nitrate (NO3-) remains poorly understood. We conducted a dual 15N labelling experiment in a semi-arid steppe in Inner Mongolia, China, where four grazing intensities (none, light, moderate and heavy) have been maintained for 9 years. Grazing increased soil pH, reduced soil moisture and organic carbon, and decreased plant biomass (particularly under heavy grazing). Moderate grazing shifted microbial biomass and composition, declining Proteobacteria and increasing Ascomycota. These changes altered plant and microbial N uptake. Plant N preference shifted from NH4+ to NO3- with increasing grazing intensity, while microbial NO3- uptake peaked under moderate grazing but declined under heavy grazing. In contrast, microbial NH4+ uptake increased nonlinearly according to a quadratic relationship, resulting in microbial dominance under heavy grazing. The microbial-to-plant uptake ratio for NH4+ revealed a tipping point, beyond which microbial uptake dominated. Our results demonstrate that grazing intensity regulates plant-microbial N competition by driving ammonium towards microbial immobilization and nitrate towards plant uptake, mediated by changes in microbial community composition. Fungal immobilization under heavy grazing drove microbial NH4+ dominance, creating a tipping point. Synthesis. These findings highlight a threshold response in below-ground nutrient partitioning and suggest that moderate grazing sustains balanced plant-microbe interactions in grassland ecosystems. This study provides a mechanistic framework based on a fungal-driven NH4+ tipping point, revealing critical competition thresholds that are not detectable in bulk N measurements. |
| URL标识 | 查看原文 |
| WOS关键词 | NITROGEN ; DIVERSITY ; HERBIVORES ; IMPACTS |
| WOS研究方向 | Plant Sciences ; Environmental Sciences & Ecology |
| 语种 | 英语 |
| WOS记录号 | WOS:001711007200001 |
| 出版者 | WILEY |
| 源URL | [http://ir.igsnrr.ac.cn/handle/311030/221306]  |
| 专题 | 生态系统网络观测与模拟院重点实验室_外文论文 |
| 通讯作者 | Xu, Xingliang |
| 作者单位 | 1.Chinese Acad Agr Sci, Inst Grassland Res, Hohhot, Peoples R China 2.Beijing Normal Univ, Fac Geog Sci, Sch Nat Resources, Beijing, Peoples R China; 3.Beijing Normal Univ, Fac Geog Sci, State Key Lab Earth Surface Proc & Disaster Risk R, Beijing, Peoples R China; 4.Univ Chinese Acad Sci, Coll Resources & Environm, Beijing, Peoples R China; 5.Chinese Acad Sci, Inst Geog Sci & Nat Resources Res, Key Lab Ecosyst Network Observat & Modeling, Beijing, Peoples R China; |
| 推荐引用方式 GB/T 7714 | Iqbal, Majid,Liu, Min,Tian, Yuqiang,et al. Grazing intensity shifts plant-microbe competition for ammonium and nitrate in temperate grasslands[J]. JOURNAL OF ECOLOGY,2026,114(3):e70285. |
| APA | Iqbal, Majid.,Liu, Min.,Tian, Yuqiang.,Jin, Peng.,Yu, Chengling.,...&Xu, Xingliang.(2026).Grazing intensity shifts plant-microbe competition for ammonium and nitrate in temperate grasslands.JOURNAL OF ECOLOGY,114(3),e70285. |
| MLA | Iqbal, Majid,et al."Grazing intensity shifts plant-microbe competition for ammonium and nitrate in temperate grasslands".JOURNAL OF ECOLOGY 114.3(2026):e70285. |
入库方式： OAI收割
来源：地理科学与资源研究所
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