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Impact of nitrogen and phosphorus additions on soil gross nitrogen transformations in a temperate desert steppe |
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| Authors: | Ping Yue Jinbo Zhang Gaodi Zhu Xiaoyue Yin Xiaoxue Zhang Shaokun Wang Christoph Müller Tom Misselbrook Xiaoan Zuo |
| Affiliation: | 1. Yinshanbeilu Grassland Eco-hydrology National Observation and Research Station, China Institute of Water Resources and Hydropower Research, Beijing, China;2. School of Geography, Nanjing Normal University, Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing, China;3. State Key Laboratory of Subtropical Silvi culture, Zhejiang A&F University, Hangzhou, China Contribution: Methodology;4. Institute of Qinghai-Tibet Plateau, Southwest Minzu University, Chengdu, China Contribution: Data curation;5. Urat Desert-grassland Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Science, Lanzhou, China Naiman Desertification Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China Key Laboratory of Stress Physiology and Ecology, Lanzhou, China Contribution: Data curation;6. Urat Desert-grassland Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Science, Lanzhou, China Naiman Desertification Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China Key Laboratory of Stress Physiology and Ecology, Lanzhou, China Contribution: Data curation, Investigation;7. Department of Plant Ecology (IFZ), Justus-Liebig University Giessen, Giessen, Germany School of Biology and Environmental Science, University College Dublin, Dublin, Ireland Contribution: Software, Methodology;8. Department of Sustainable Soils and Grassland Systems, Rothamsted Research, North Wyke, Devon, UK Contribution: Writing - review & editing;9. Urat Desert-grassland Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Science, Lanzhou, China |
| Abstract: | Nutrient addition has a significant impact on plant growth and nutrient cycling. Yet, the understanding of how the addition of nitrogen (N) or phosphorus (P) significantly affects soil gross N transformations and N availability in temperate desert steppes is still limited. Therefore, a 15N tracing experiment was conducted to study these processes and their underlying mechanism in a desert steppe soil that had been supplemented with N and P for 4 years in northwestern China. Soil N mineralization was increased significantly by P addition, and N and P additions significantly promoted soil autotrophic nitrification, rather than NH4+-N immobilization. The addition of N promoted dissimilatory NO3− reduction to NH4+, while that of P inhibited it. Soil NO3−-N production was greatly increased by N added alone and by that of N and P combined, while net NH4+-N production was decreased by these treatments. Soil N mineralization was primarily mediated by pH, P content or organic carbon, while soil NH4+-N content regulated autotrophic nitrification mainly, and this process was mainly controlled by ammonia-oxidizing bacteria rather than archaea and comammox. NH4+-N immobilization was mainly affected by functional microorganisms, the abundance of narG gene and comammox Ntsp-amoA. In conclusion, gross N transformations in the temperate desert steppe largely depended on soil inorganic N, P contents and related functional microorganisms. Soil acidification plays a more key role in N mineralization than other environmental factors or functional microorganisms. |
| Keywords: | 15N diffusion technique desert grassland functional genes soil gross N transformations |