Assessing strategies to mitigate phosphorus leaching from drained clay soils.

Assessing mitigation of phosphorus (P) leaching from subsurface drainage systems is challenging due to high spatial and temporal variation in leaching. Mean measured total P leaching from a clayey soil in an eight-year study period (four replicates per treatment) was (kg ha year): 1.21 from shallow autumn tillage (ShT), 0.