title: Surface applied water treatment residuals affect bioavailable phosphorus losses in Florida sands.
abstract: Water treatment residuals (WTR) can reduce runoff P loss and surface co-application of P-sources and WTR is a practical way of land applying the residuals. In a rainfall simulation study, we evaluated the effects of surface co-applied P-sources and an Al-WTR on runoff and leacheate bioavailable P (BAP) losses from a Florida sand. Four P-sources, namely poultry manure, Boca Raton biosolids (high water-soluble P), Pompano biosolids (moderate water-soluble P), and triple super phosphate (TSP) were surface applied at 56 and 224 kg P ha(-1) (by weight) to represent low and high soil P loads typical of P- and N-based amendments rates. The treatments further received surface applied WTR at 0 or 10 g WTR kg(-1) soil. BAP loss masses were greater in leachate (16.4-536 mg) than in runoff (0.91-46 mg), but were reduced in runoff and leachate by surface applied WTR. Masses of total BAP lost in the presence of surface applied WTR were less than approximately 75% of BAP losses in the absence of WTR. Total BAP losses from each of the organic sources applied at N-based rates were not greater than P loss from TSP applied at a P-based rate. The BAP loss at the N-based rate of moderate water-soluble P-source (Pompano biosolids) was not greater than BAP losses at the P-based rates of other organic sources tested. The hazards of excess P from applying organic P-sources at N-based rates are not greater than observed at P-based rates of mineral fertilizer. Results suggest that management of the environmental P hazards associated with N-based rates of organic materials in Florida sands is possible by either applying P-sources with WTR or using a moderate water-soluble P-source.
authors.affiliation: Crop and Soil Science Department, 512 Plant and Soil Science Bldg., Michigan State University, East Lansing, MI 48824, USA. ooladeji@msu.edu
authors.forename: Olawale O
authors.initials: OO
authors.lastname: Oladeji
authors.forename: George A
authors.initials: GA
authors.lastname: O'Connor
authors.forename: Scott R
authors.initials: SR
authors.lastname: Brinton
mesh_terms: D001682:Biological Availability; D005431:Florida; D010758:Phosphorus / Q000493:pharmacokinetics*; D012822:Silicon Dioxide; D014881:Water Supply / Q000032:analysis*
chemical_list: D010758:Phosphorus; D012822:Silicon Dioxide