Phosphorus Drawdown Study

Nutrient Cycling and Nutrient Use Efficiency in Manure Treated Soils

Conducted by USDA-ARS, Kimberly, Idaho, the, Phosphorus Drawdown Study is a follow-up to the Long-Term Manure Study. After eight years of repeated manure application, the Phosphorus Drawdown study will evaluate the effectiveness of different cropping rotations to bring elevated soil test P levels down to agronomic levels. This project will also evaluate residual nitrogen mineralization rates from past manure applications. Cropping rotations include a triticale/silage corn rotation that is typical of southern Idaho and alternative crops such as canola, sorghum-sudangrass, and forage barley.