Key Found to Phosphorus Movement

Phosphorus can fuel excessive growth of algae and other plant matter in freshwater ecosystems. But, scientists for the Agricultural Research Service have discovered a key to mitigating the amount of phosphorus that can accumulate in water percolating through the soil. They say solid dairy manure is better than commercial fertilizer. And liquid dairy manure is worse. These findings could help farmers in the semiarid western United States protect local watersheds from agricultural pollutants.

The scientists also observed that liquid manure and solid manure differed significantly in their carbon compound makeup, which may contribute to the resulting variations in the manure leachates. Other factors may also play a part in the dynamics of phosphorus leaching, including microbial activity and metal content in the soil and the ability of clay particles in the soil to attract and hold onto phosphorus.

The work was done at the ARS Northwest Irrigation and Soils research laboratory in Kimberly, Idaho.