NUTRIENT RUN-OFF FOLLOWING APPLICATION OF LIVESTOCK WASTES TO GRASSLAND

Three types of farm waste (cattle slurry, dirty water and farm yard ma nure (FYM)) were applied to hydrologically isolated grassland plots on a sloping poorly draining soil. Two applications were made, the first in October and the second in February. Application rates were 50 m(3) ha(-1) of slurry and dirty water and 50 t ha(-1) of FYM. Volumes of r un-off following rainfall events and concentrations of N, P and K in r un-off were measured. Losses of nutrients were highel following applic ations made with the soil at field capacity and rainfall soon after ap plication. In terms of percentage loss of applied nutrients, losses we re generally low. Concentration of N in run-off from the dirty water a nd FYM treated plots following the first application and the slurry tr eated plots following the second application exceeded 11.3 mg dm(-3) ( a recommended limit for drinking water) although the maximum concentra tion recorded was 15 mg dm(-3) following FYM application. Concentratio n of P in run-off only exceeded 1 mg dm(-3) following the second appli cation of cattle slurry. Concentration of K exceeded 10 mg dm(-3) foll owing the first application of FYM and the second application of cattl e slurry.