Phosphorus Dynamics in Broiler Litter-Amended Soils

Because land application of broiler litter is commonly made in the spring before cropping season and in the fall, it is essential to understand how environmental variations, such as temperature, affect the phosphorus (P) dynamics. A laboratory incubation study was conducted at Waste Management and Forage Research Unit, USDAARS with the objective of determining the effects of temperature and soil properties on water-soluble P (WSP), Mehlich 3 P, and P fractions in broiler litter-amended soils. Broiler litter was mixed with three soils (Leeper silty clay, Grenada silt loam, and Ruston sandy loam) at the rate of 10 Mg ha. The mixtures were incubated at 188C, 258C, and 328C for up to 90 days and repeated three times. Soil samples were taken at eight time intervals (2, 5, 10, 15, 30, 60, and 90 days) and analyzed for water-soluble P and Mehlich 3-extractable P (MEP). Phosphorus also was fractionated chemically into inorganic and organic components by sequential extraction for soil samples taken at the end of incubation period (90 days). Water-soluble P decreased rapidly after a 15-day incubation in all soils for all temperatures and followed to a steady state to the end of incubation period. Averaged across temperatures, broiler litter application resulted in a significant increase in all fractions compared with controls. However, the increase was greater for inorganic than for organic fractions. The concentration of calcium (Ca)-P fraction was highest in calcareous Grenada soil, which suggests that the presence of carbonates influence the fate of P from applied broiler litter. The coarse textured Ruston contained a greater concentration of water-soluble P (WSP) than the other soils. At 328C, the concentration of plantavailable P fractions [bicarbonate inorganic P (IP) and hydroxide IP] significantly Received 4 December 2003, Accepted 17 June 2004 Contribution of the Mississippi Agricultural and Forestry Experiment Station, journal paper no. J10120. Address correspondence to A. Adeli, USDA-ARS, Waste Management and Forage Research Unit, Mississippi State, MS 39672, USA. E-mail: [email protected]. usda.gov Communications in Soil Science and Plant Analysis, 36: 1099–1115, 2005 Copyright # Taylor & Francis, Inc. ISSN 0010-3624 print/1532-2416 online DOI: 10.1081/CSS-200056876 1099 D o w n l o a d e d B y : [ U S D A N a t l A g r i c u l t u l L i b ] A t : 2 0 : 3 4 3 0 D e c e m b e r 2 0 0 9 increased and WSP decreased. It is likely that the higher temperature (328C) promotes higher biological activity and lower water-soluble P than lower temperature.