Hao Yueqi, Liu Hao, Li Jiawei, Mu Li
Key Laboratory for Environmental Factors Control of Agro-product Quality Safety (Ministry of Agriculture and Rural Affairs), Tianjin Key Laboratory of Agro-environment and Safe-product, Institute of Agro-environmental Protection, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China.
Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education)/Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300080, China.
iScience. 2024 Dec 19;28(1):111634. doi: 10.1016/j.isci.2024.111634. eCollection 2025 Jan 17.
Nitrogen-fixing microorganisms (NFMs) are important components of soil N sinks and are influenced by multiple environmental factors. We established a random forest model optimized by the distributed delayed particle swarm optimization (RODDPSO) algorithm to analyze the global NFM data. Soil pH, organic carbon (OC), mean annual precipitation (MAP), altitude, and total phosphorus (TP) are factors with contributions greater than 10% to NFMs. pH, OC, and MAP are the top three factors at the global scale. The tipping points of pH and OC for the NFMs were 7.84 and 2.71%, respectively. The contribution of MAP first increased but then decreased with peak value at 1,265.65 mm. Under the scenario SSP 8.5, 12% of the NFMs increase occur in Africa in 2100; 16% and 36% of the NFMs decrease in North America and Oceania in 2100, respectively. Our work created a global NFMs map and identified the critical tipping points.
固氮微生物（NFMs）是土壤氮汇的重要组成部分，且受到多种环境因素的影响。我们建立了一种通过分布式延迟粒子群优化（RODDPSO）算法优化的随机森林模型，以分析全球固氮微生物数据。土壤pH值、有机碳（OC）、年均降水量（MAP）、海拔和总磷（TP）是对固氮微生物贡献大于10%的因素。pH值、OC和MAP是全球尺度上的前三大因素。固氮微生物的pH值和OC的临界点分别为7.84和2.71%。MAP的贡献先增加后减少，峰值为1265.65毫米。在共享社会经济路径（SSP）8.5情景下，到2100年，12%的固氮微生物增加发生在非洲；到2100年，北美洲和大洋洲的固氮微生物分别减少16%和36%。我们的工作创建了全球固氮微生物地图并确定了关键临界点。
