Long-term manure and fertilizer application effects on phosphorus and nitrogen in runoff. Transactions of the American Society of Agricultural Engineers

ABSTRACT. Long–term manure and fertilizer applications to a soil can increase phosphorus (P) and nitrogen (N) transport in runoff. This study was conducted to determine P and N transport in runoff following long–term (since 1953) manure and fertilizer applications. Duplicate soil samples (32) were collected in 1998 from the top 0.1 m of selected plots of a long–term manure and fertilizer applications field experiment and later placed in 1 m2 soil pans in the laboratory. Manure and fertilizer were mixed with 16 of the soil samples, while no treatment was applied to the other half (long–term residual effect). Simulated rainfall was then applied to the soil during initial and wet (24 hours later) events. Manure added just before simulated rainfall resulted in significantly greater concentrations of dissolved P (DP)