%0 Journal Article
%T Temperature Effects on Phosphorus Release from a Biosolids-Amended Soil
%A Maria L. Silveira
%A George A. O'Connor
%J Applied and Environmental Soil Science
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/981715
%X This study was designed to evaluate the effects of temperature on the potential leachable P pool and distribution of chemical P forms in a biosolids-amended soil. A P-deficient Spodosol was incubated with seven biosolids and inorganic P fertilizer at 20 and 32¡ãC for 90 days. Amendments were applied to provide a total P concentration of 112£¿mg£¿kg£¿1 soil, which correspond to a field application of ~224£¿kg£¿P£¿ha£¿1. Cumulative P mass leached during the 90£¿d study for any P source was <2% of the applied P, but greater cumulative P mass was released from the biological P removal and composted biosolids than from the heat-dried materials. Increasing temperature (20 to 32¡ãC) generally decreased cumulative P mass leached, suggesting greater soil affinity to retain P at 32¡ãC than at 20¡ãC. In a static incubation experiment (no leaching), soil water-extractable P concentrations were reduced over time, but no temperature effect was observed. Similarly, P distribution among the various fractions was not affected by temperature. The relatively great ability of the soil to sorb P masked differences in biosolids properties and the potential impacts of temperature on P lability. Additional work using low P-sorbing soils is warranted. 1. Introduction Biosolids can provide essential nutrients to plant and improve soil chemical, physical, and biological properties [1]. However, repeated biosolids applications based on plant N requirements supply P in excess of crop requirements, resulting in soil P accumulation. Environmental concerns associated with the buildup of soil P and potential losses of P movement to water bodies via surface runoff, vertical leaching, and erosion exist. Although P is typically immobile in most soils, coarse-textured soils are prone to P transport [2]. Florida Spodosols are particularly susceptible to P leaching due to the lack of reactive minerals, low Fe and Al oxides, and organic matter concentrations in surface horizons [3]. Moreover, poorly drained Spodosols associated with relatively shallow water tables intercepted by drainage ditches increase the potential risks of P edge-field losses. Phosphorus lability in biosolids-treated soils depends on the forms of P is initially present in the biosolids and the characteristics of the soil receiving the residual. The wastewater treatment processes strongly influence the chemistry and P pools in biosolids [4]. For instance, biological P removal (BPR) processes can increase P extractability and runoff losses [5, 6]. Conversely, biosolids treated with Al and Fe or heat-dried materials generally exhibit
%U http://www.hindawi.com/journals/aess/2013/981715/