Phosphorus transformation in poultry litter and litter-treated Oxisol of Brazil assessed by 31P-NMR and wet chemical fractionation

• Published in: Revista Brasileira de Ciência do Solo 2012-11, Vol.36 (5), p.1516-1527
• Main Authors: Souza, César Roriz de, Ghosh, Amlan Kumar, Silva, Ivo Ribeiro da, Alvarenga, Elson Santiago de, Novais, Roberto Ferreira, Jesus, Guilherme Luiz de
• Format: Article
• Language: English
• Subjects: fracionamento do P; fósforo orgânico; materiais de forração; pirofosfatos; SOIL SCIENCE
• ISSN: 0100-0683; 1806-9657; 0100-0683
• DOI: 10.1590/S0100-06832012000500016

Large quantities of poultry litter are being produced in Brazil, which contain appreciable amounts of phosphorus (P) that could be of environmental concern. To assess the immediate environmental threat, five poultry litters composed of diverse bedding material were incubated for 43 days under greenhouse conditions. The litters consisted of: coffee bean husk (CH); wood chips (WC); rice husk (RH); ground corn cobs (CC) and ground napier grass (NG) (Pennisetum purpureum Schum.), in which the change in forms of soluble P was evaluated using 31P NMR spectroscopy. On average, 80.2 and 19.8 % of the total P in the extract, respectively, accounted for the inorganic and organic forms before incubation and 48 % of the organic P was mineralized to inorganic P in 43 days of incubation. Wide variation in the organic P mineralization rate (from 82 % -WC to 4 % - NG) was observed among litters. Inorganic orthophosphate (99.9 %) and pyrophosphate (0.1 %) were the only inorganic P forms, whereas the organic P forms orthophosphate monoesters (76.3 %) and diester (23.7 %) were detected. Diester P compounds were mineralized almost completely in all litters, except in the CH litter, within the incubation period. Pyrophosphates contributed with less than 0.5% and remained unaltered during the incubation period. Wood-chip litter had a higher organic P (40 %) content and a higher diester: monoester ratio; it was therefore mineralized rapidly, within the first 15 days, achieving steady state by the 29th day. Distinct mineralization patterns were observed in the litter when incubated with a clayey Oxisol. The substantial decrease observed in the organic P fraction (Po) of the litter types followed the order: CH (45 %) > CC (25 %) > RH (13 %) ≈ NG (12 %) > WC (5 %), whereas the Pi fraction increased. Incubation of RH litter in soil slowed down the mineralization of organic P. A avicultura intensiva tem se expandido bastante nos últimos anos no Brasil e, com isso, gerado grandes quantidades de cama de aviário. Esses materiais contêm quantidades substanciais de fósforo (P) - nutriente altamente limitante ao crescimento de plantas nos solos mais intemperizados, mas que pode causar impactos ambientais negativos se inadequadamente manejado. A fim de melhor subsidiar o uso mais sustentável desses materiais orgânicos, o presente trabalho teve como objetivo avaliar as formas e as transformações de P de camas de aviário obtidas com cinco diferentes materiais de forração do piso: casca de caf