International Study Finds Plant Diversity Can Reduce Nitrogen Fertilizer Reliance

An international study led by Trinity College, Dublin, and published in Science found that higher plant diversity in agricultural grasslands increases yields even with lower inputs of nitrogen fertilizer. An experiment conducted at 26 temperate-climate sites across the globe evaluated adding multiple additional species to monoculture grasslands or two-species grass/legume fields. The results showed that multispecies mixtures achieved high yields due to strong grass-legume and legume-herb synergistic interactions; that is, the yield of the mixtures was much greater than the sum of the parts. Researchers found that sowing two grasses, two legumes, and two herbs, each in approximately equal proportions, optimizes yield and nitrogen-saving benefits. This six-species multispecies mixture produced 11% more yield than a field with a single grass species, even when half as much nitrogen fertilizer was applied.

Related ATTRA resource: Toolkit: How to Reduce Synthetic Fertilizer Use