More diverse rhizobial communities can lead to higher symbiotic nitrogen fixation rates, even in nitrogen-rich soils

Symbiotic nitrogen fixation (SNF) by legumes and their rhizobial partners is one of the most important sources of bioavailable nitrogen to terrestrial ecosystems. While most work on the regulation of SNF has focused on abiotic drivers such as light, water, and soil nutrients, the diversity of rhizobia with which an individual legume partners may play an important but under-recognized role in regulating nitrogen inputs from SNF. By experimentally manipulating the diversity of rhizobia available to legumes, we demonstrate that rhizobial diversity can increase average SNF rates by more than 90%, and that high rhizobial diversity can induce increased SNF even under conditions of high soil N fertilization. However, the effects of rhizobial diversity, the conditions under which diversity effects were strongest, and the likely mechanisms driving these diversity effects differed between the two legume species we assessed. These results provide evidence that biodiversity-ecosystem function relat..., Data were collected from a greenhouse experiment conducted at the Smithsonian Environmental Research Center in 2019. Two legume species (Spartium junceum and Ulex europaeus) were exposed to different levels of rhizobial diversity (0 to 5 rhizobial taxa) and different levels of nitrogen fertilization (0 to 20 g/m2/yr). Data represent biomass, biomass allocation, and nitrogen fixation metrics measured on 1100 plants following a five-month growth period., , # More diverse rhizobial communities can lead to higher symbiotic nitrogen fixation rates, even in nitrogen-rich soils

[https://doi.org/10.5061/dryad.qrfj6q5qp](https://doi.org/10.5061/dryad.qrfj6q5qp)

## Description of the data and file structure

This repository contains three files with data and corresponding code related to a greenhouse experiment where two legume species were exposed to different treatments of nitrogen fertilization and rhizobial diversity. Numerous metrics of plant growth and nitrogen fixation were measured. The \"biomass\" data file contains biomass data on all ~1,100 plants in the experiment. The \"Nfix data\" file contains data on the subset of individuals in each treatment that were sent for 15N isotopic analysis to calculate N fixation at the end of the experiment. The R code file requires both data files to run completely. 

#### Data File 1: Rhizdiv\_postprocess\_biomass\_data\_1-2023.csv

This file contains biomass data for all 1100 plants in the experiment....