Pasture Runoff Water Quality from Application of Inorganic and Organic Nitrogen Sources
1984
Mc Leod, R. V. | Hegg, R. O.
Surface runoff water quality from a rescue pasture receiving surface application of organic wastes and commercial fertilizer was evaluated at Clemson University (Clemson, S.C.). Dairy manure, poultry manure, and municipal sludge were the organic wastes used in this experiment. Ammonium nitrate was the commercial fertilizer. The organic wastes and commercial fertilizer were applied at the rate of 112 kg N ha⁻¹ to eight plots during four different periods. Due to an extremely dry year, runoff events were produced by irrigation. The runoff water was collected and samples were analyzed for pH, total P, total suspended solids, total Kjeldahl N, NH₄-N, NO₃-N, and chemical oxygen demand. The nutrient concentrations in surface runoff were more dependent on the number of rainfalls since application of the fertilizer than on the quantity of rainfall or runoff. The concentrations of potential pollutants from surface-applied organic wastes or commercial fertilizer were reduced by between 80 and 55% after two runoff events. The NO₃-N concentration in the surface runoff from the plots receiving the commercial fertilizer exceeded the permissible public water supply standard during the first runoff event. The overall nutrient loss in the runoff was found to be minimal (< 4% of total Kjeldahl N and chemical oxygen demand and < 2.5% of total P).
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