This data includes information about nitrogen fixation, phosphatase activity, plant nitrogen and phosphorus demand and soil nitrogen and phosphorus availability of nitrogen-fixing and non-fixing trees from seven species grown in an experimental plantation at the Agua Salud Native Species Plantation, El Giral, Panama (9°12'50.15''N, 79°43'26''W). Data were collected by the Smithsonian Tropical Research Institute and Princeton University and were analysed by the University of Leeds. This work was funded by the following organisations: Heising-Simons Foundation, Hoch Family, ForestGEO®, HSBC, Stanley Motta, Small World Institute Fund, Smithsonian Institution's Competitive Grants for Science, Smithsonian Institution's Grand Challenges, National Science Foundation (award reference: EAR-1360391), National University of Singapore, Smithsonian Tropical Research Institute, Yale-NUS college, Princeton University, Princeton Environmental Institute, Princeton Carbon Mitigation Initiative, University of Leeds and NERC (award reference: NE/M019497/1) Full details about this dataset can be found at https://doi.org/10.5285/3578bae2-4b88-4b2e-93e1-6965dfe1348c