Quantity and quality of runoff water from freshly manured agricultural soils

Water quality concerns stemming from agricultural non-point source pollution of Alberta's surface waters prompted a study examining effects of freshly applied and incorporated manure on hydraulic characteristics and nutrients in runoff. Phosphorus and nitrogen in runoff increased with manure application rate although hydraulic characteristics remained unchanged. Nutrient fractions in runoff decreased or remained unchanged with manure incorporation, excluding nitrates, which increased. Hydraulic responses of the soil and landscape varied with manure incorporation between sites. Manure incorporation increased infiltration at the site with fine textured soils and decreased infiltration at the no-till managed site. Phosphorus fractions in runoff correlated to total phosphorus in manure and soil-test phosphorus with similar r 2 values while correlations to water extractable phosphorus in manure had lower r2 values. Over thirty minutes of runoff, nitrogen concentrations decreased while phosphorus concentrations remained relatively constant. Nitrogen and phosphorus loads increased with time due to increasing runoff rates.