Low nitrate leaching determined by threshold for cover crop biomass

We investigated nitrate leaching during four years in a long-term crop rotation experiment, and the effect of legume-based cover crops (CC).

Cover crops reduced nitrate leaching by approximately 60%, but this effect varied from year to year; variation in CC biomass best explained the reduction in nitrate leaching. To reduce nitrate leaching to a low and stable level a minimum amount of CC biomass was needed.