Evaluating Cattle Manure Application Strategies on Phosphorus and Nitrogen Losses from a Florida Spodosol

• Published in: Agronomy journal 2010-09, Vol.102 (5), p.1511-1520
• Main Authors: Obour, A.K, Silveira, M.L, Vendramini, J.M.B, Adjei, M.B, Sollenberger, Lynn E
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; ammonium nitrate; ammonium nitrogen; application timing; Biological and medical sciences; Cattle manure; eutrophication; forage grasses; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; groundwater; hydrochemistry; leaching; losses from soil; nitrate nitrogen; nitrogen; Other nutrients. Amendments. Solid and liquid wastes. Sludges and slurries; Paspalum notatum; pastures; phosphorus; soil depth; soil fertility; soil test values; Soil-plant relationships. Soil fertility. Fertilization. Amendments; Spodosols; surface water; water table; wells
• ISSN: 0002-1962; 1435-0645
• DOI: 10.2134/agronj2010.0275

Repeated application of cattle (Bos taurus) manure to agricultural areas often results in soil P accumulation, which may pose risks to surface waters. We evaluated seven different application strategies on P and N losses from an established bahiagrass (Paspalum notatum Flügge) pasture: control (no N applied); two N sources [manure alone or manure plus ammonium nitrate (AN) (50/50% combination)]; two application frequencies (single or split); and two N rates (200 and 400 kg N ha−1). Shallow groundwater P was monitored using piezometers installed at 60 cm (shallow wells) and 120 cm (deep wells). Surface runoff collectors were used to monitor runoff N and P from naturally occurring rainfall events. Soil samples were analyzed for Mehlich-1 P and KCl-extractable NH4–N and NO3–N concentrations. Application of manure in combination with AN suppressed leachate P, but no effect was observed on leachate NO3–N concentrations in the shallow wells. Application of manure alone or in combination with AN did not affect P and N concentrations in the deep wells. Applying manure plus AN resulted in approximately 50% reduction in runoff N and P loads than treatments receiving manure alone. Manure applied alone or in combination with AN increased soil test P in upper soil horizons relative to control plots. Conversely, application of either manure or manure plus AN had no effect on soil NH4–N and NO3–N concentrations. Results demonstrate that combining manure application with inorganic N fertilizer represents an environmentally sound application strategy to reduce soil P and N accumulation and subsequent risks of nutrient transport.