Phosphorus and Nitrogen in Runoff Following Beef Cattle Manure of Compost Application

Manure or compost from beef cattle feedlots can be an excellent sources of nutrients and organic matter when added to soils, but they can also pollute runoff. We determined the effects of simulated rainfall on runoff losses of P and N, and EC and pH following application of manure and compost to a Sharpsburg silty clay loam (fine smectitic, mesic Typic Argiudoll) soil having grain sorghum [Sorghum bicolor (L.) Moench] and winter wheat (Triticum aestivum L.) residues. Manure, compost, and fertilizer were applied to no-till fields at rates required to meet N or P requirements for corn (Zea mays L.) production and were either left on the soil surface or disked to 8 cm. There were also untreated checks. Runoff concentrations of dissolved P (DP), bioavailable P (BAP), and NH4—N were significantly greater when the soil was not disked. Total and particulate P concentrations in runoff were generally less under wheat than sorghum residue and were less for the no-till than the disked condition. In the disked system, N or P-based manure or compost application resulted in DP concentration \u3c1 mg L-1. Manure and compost application resulted in greater runoff EC values than fertilizer application. Phosphorus concentration of runoff receiving P fertilizer or N-based manure and compost application can be an environmental concern when these sources are applied under no-till conditions without incorporation