Urochloa grasses swap nitrogen source when grown in association with legumes in tropical pastures
The degradation of tropical pastures sown with introduced grasses (e.g., Urochloa spp.) has
dramatic environmental and economic consequences in Latin America. Nitrogen (N) limitation to
plant growth contributes to pasture degradation. The introduction of legumes in association with
grasses has been proposed as a strategy to improve N supply via symbiotic N2 fixation, but the fixed
N input and N benefits for associated grasses have hardly been determined in farmers’ pastures.