Grazing management and buffer strips impact pasture phosphorus runoff

One of the main environmental concerns with surface application of poultry litter to pastures is phosphorus (P) runoff. Most of the P runoff from pastures is in the soluble form, which is contributing to accelerated eutrophication in waterbodies.

Research has shown benefits of implementing buffer strips and rotational grazing to reduce P runoff from pastures. However, few long-term studies have been conducted on the effects of a combination of best management practices, such as rotational grazing with buffer strips on P losses from pastures.

A 14-year study published in the Journal of Environmental Quality evaluates the effects of grazing management strategies and buffer strips on P runoff from pastures receiving surface applications of poultry litter. Both continuous and rotational grazing had similar effects on P runoff. However, implementing unfertilized buffer strips or unfertilized fenced riparian buffer strips reduced P loads in runoff from fields under rotational grazed management by 36 and 60%, respectively, whereas converting pastures to hayfields reduced P runoff by 49% compared with continuous grazing.

The use of unfertilized buffer strips or unfertilized fenced riparian buffer strips combined with rotational grazing or converting pastures to hayfields is effective for reducing P runoff in U.S. pasture systems.