Global terrestrial nitrogen fixation and its modification by agriculture

• 成果类型: Article
• 署名作者: Reis Ely, Carla R.; Perakis, Steven S.; Cleveland, Cory C.; Menge, Duncan N. L.; Reed, Sasha C.; Taylor, Benton N.; Batterman, Sarah A.; Clark, Christopher M.; Crews, Timothy E.; Dynarski, Katherine A.; Gei, Maga; Gundale, Michael J.; Herridge, David F.; Jovan, Sarah E.; Kou-Giesbrecht, Sian; Peoples, Mark B.; Piipponen, Johannes; Rodriguez-Caballero, Emilio; Salmon, Verity G.; Soper, Fiona M.; Staccone, Anika P.; Weber, Bettina; Williams, Christopher A.; Wurzburger, Nina
• 署名单位: Oregon State University; United States Department of the Interior; United States Geological Survey; University of Montana System; University of Montana; Columbia University; United States Department of the Interior; United States Geological Survey; Harvard University; Cary Institute of Ecosystem Studies; University of Leeds; Smithsonian Institution; Smithsonian Tropical Research Institute; United States Environmental Protection Agency; Swedish University of Agricultural Sciences; University of New England; United States Department of Agriculture (USDA); United States Forest Service; Dalhousie University; Commonwealth Scientific & Industrial Research Organisation (CSIRO); CSIRO Agriculture & Food; Aalto University; Universidad de Almeria; Universidad de Almeria; Max Planck Society; United States Department of Energy (DOE); Oak Ridge National Laboratory; United States Department of Energy (DOE); Oak Ridge National Laboratory; McGill University; McGill University; University of Graz; Clark University; University System of Georgia; University of Georgia; Oak Ridge Associated Universities; United States Department of Energy (DOE); Oak Ridge Institute for Science & Education
• 刊物名称: Nature
• ISSN/ISSBN: 0028-3289
• DOI: 10.1038/s41586-025-09201-w
• 发表日期: 2025-07-17
• 关键词: net primary productivity; n-2 fixation; fixing trees; carbon; limitation; abundance; patterns; legumes; cycles

摘要

Biological nitrogen fixation (BNF) is the largest natural source of new nitrogen (N) that supports terrestrial productivity1,2, yet estimates of global terrestrial BNF remain highly uncertain3,4. Here we show that this uncertainty is partly because of sampling bias, as field BNF measurements in natural terrestrial ecosystems occur where N fixers are 17 times more prevalent than their mean abundances worldwide. To correct this bias, we develop new estimates of global terrestrial BNF by upscaling field BNF measurements using spatially explicit abundances of all major biogeochemical N-fixing niches. We find that natural biomes sustain lower BNF, 65 (52-77) Tg N yr-1, than previous empirical bottom-up estimates3,4, with most BNF occurring in tropical forests and drylands. We also find high agricultural BNF in croplands and cultivated pastures, 56 (54-58) Tg N yr-1. Agricultural BNF has increased terrestrial BNF by 64% and total terrestrial N inputs from all sources by 60% over pre-industrial levels. Our results indicate that BNF may impose stronger constraints on the carbon sink in natural terrestrial biomes and represent a larger source of agricultural N than is generally considered in analyses of the global N cycle5,6, with implications for proposed safe operating limits for N use7,8.