Submitted to: Journal of Soils and Sediments
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/12/2011
Publication Date: 1/20/2012
Citation: Szogi, A.A., Bauer, P.J., Vanotti, M.B. 2012. Vertical distribution of phosphorus in a sandy soil fertilized with recovered manure phosphates. Journal of Soils and Sediments. 12:334-340. Interpretive Summary: Phosphorus is an essential nutrient and a major limiting factor for plant growth in soils with low phosphorus content. In regions with a high density of confined animal production, recurrent land application of manure phosphorus at rates that exceed crop removal rates is a major concern for its potential to pollute water resources. On the other hand, mineral phosphorus is a non-renewable resource whose supply relies on dwindling rock phosphate reserves. Global demand for mineral phosphorus is mounting due to the increased demand of agricultural production in response to rising world population. Together, environmental concerns and global phosphorus scarcity forecasts have stimulated the interest on manure phosphorus recovery as an alternative to simple land disposal of animal waste. A greenhouse study was conducted to evaluate the vertical distribution of phosphorus in a sandy Coastal Plain soil of the southern U.S. Soil columns were fertilized with recovered phosphorus from liquid pig manure and solid broiler litter, raw broiler litter, and commercial phosphate. All soil columns were percolated with distilled water for eight weeks. At the end of the eight weeks, the vertical soil phosphorus distribution showed that most of the phosphorus applied with recovered manure phosphorus, and raw broiler materials remained within the top soil, where they were initially applied. The only fertilizer treatment that showed a significant higher phosphorus concentration below the topsoil was the commercial phosphate. These results indicated down movement and potential phosphorus losses only for the applied commercial phosphate. Recovery and reuse of manure phosphorus could improve the sustainability of animal production by reducing phosphorus losses to the environment and provide an effective phosphorus fertilizer for crop production.
Technical Abstract: Purpose: To evaluate the environmental fate of recovered manure phosphates to provide application recommendations for their use as crop fertilizers. Materials and methods: A greenhouse study was conducted to evaluate the leaching potential and vertical distribution of total and plant available phosphorus (P) in a deep sandy Coastal Plain soil of the southern United States fertilized with recovered P from liquid pig manure (SRP) and solid broiler litter (LRP). The recovered manure P sources were compared to commercial triple superphosphate (TSP) and raw broiler litter (BL) applied at a single rate of 170 kg P2O5/ha to 71-cm-tall soil columns with and without cotton plants. All materials were uniformly mixed into the surface 15 cm of soil in each column. All treated and control (unfertilized) soil columns were leached weekly with distilled water for 8 weeks. The water obtained after leaching the soil columns was analysed for total P. Cotton plant material was analysed for P content, and the soil columns were sectioned to determine the vertical distributions of total and plant available P (Mehlich 3 test). Result and discussion: The vertical soil P distribution showed that most of the total and plant available P applied with SRP, LRP, and BL materials remained within the top 15 cm of the soil columns, where materials were initially applied. The significant increase of both total and soil available P within 15-22.5 cm of soil columns treated with TSP indicated translocation and potential leaching of P applied as TSP. In the short term of this study (eight weeks), the soil leaching potential of both LRP and SRP was lower than the more water-soluble commercial P fertilizers such as TSP. Conclusions: The use of recovered P could minimize manure P losses into the environment, promote long-term sustainability of poultry and pig production, and provide a recycled P source for use as crop fertilizer.