2007 Annual Report 1a.Objectives (from AD-416) 1. Conduct two preliminary laboratory studies on sewage sludge from Fayetteville, Rogers, and Springdale. The first study will determine the effect of oxidation on soluble P in sludge; the second will determine what rates of aluminum and/or iron are needed to reduce soluble P. 2. Measure soluble P in solid and liquid manure and sewage sludge samples. The dry samples will be analyzed with both the old 1:10 (manure:water) and the new (1:100) extraction method. 3. Measure P runoff from 432 rainfall simulations using various liquid and dry manures, biosolids and commercial P fertilizers which have a range of soluble P. 4. Evaluate the data from Objective 3 to determine which method of measuring soluble P in manure and which soil test P method is more highly correlated to P runoff. 5. Develop a soluble P weighting factor in the P index for both dry and liquid manures and sewage sludge, and commercial P fertilizer. 6. Conduct a series of meetings with the Arkansas Natural Resources Commission (ANRC), Arkansas Department of Environmental Quality (ADEQ) and USDA/NRCS to present the findings of this study and further revise the index as these agencies deem appropriate. 7. Write a final report to ANRC. 1b.Approach (from AD-416) Two preliminary sewage sludge studies will be conducted to determine rates of aluminum or iron needed to precipitate soluble P. Soluble P in manures and sludge will be measured with 1:10 and 1:100 (manure:water) ratios. A total of 432 rainfalls simulations will be conducted using liquid and solid manure and sewage sludge and commercial phosphate fertilizers to determine the effects of each on phosphorus runoff. Mehlich III phosphorus in soil will be measured at two depths (0-4" and 0-6"). Regression analysis of the data will be conducted to see which method of soluble phosphorus extraction is best correlated to phosphorus loads in runoff. Using the runoff data, soluble phosphorus weighting factors will be developed for all the various types of phosphorus fertilizers (manures, sewage sludge and commercial fertilizer). We will then conduct a series of meeting with ANRC, ADEQ, and NRCS to present our findings, then write a final report to ANRC. 3.Progress Report This report serves to document research conducted under a reimbursable agreement between ARS and the Arkansas Natural Resources Commission. Additional details of research can be found in the report for the in-house associated project 6226-63000-001-00D, Poultry Manure Management Strategies to Reduce Non-Point Source Phosphorus Pollution. A total of 864 rainfall simulations will be conducted for this study using 72 small runoff plots. Forty-eight different fertilizer treatments were evaluated for this study (24 treatments/year for two years) from both organic (biosolids and manure) and inorganic sources (triple superphosphate). Multiple correlation will be used to model P runoff (P loads) from plots fertilized with various P sources using WEP and Mehlich III P as the independent variables. This information will be used to revise the Arkansas Phosphorus Index to incorporate sewage sludge.