Extractability and bioavailability of phosphorus from soils amended with poultry litter and poultry litter ash

Recycling poultry litter as a soil amendment is important to mitigate environmental problems associated with poultry waste. The application of poultry litter (PL) and poultry litter ash (PLA) may vary in their contributions to soil P concentration. An experiment was carried out to investigate the effect of PL and PLA on maize (Zea mays L.) biomass and P uptake in sand dune and masa soils. For this purpose, PL was ashed at 600 degrees C. Both PL and PLA were applied at the rate of P 100, 200 and 300 kg ha(-1). Results showed that soils amended with PLA were richer in available P and produced higher maize biomass than PL-treated soils. Plant growth increased under increasing application of PL and PLA. Masa soil produced higher biomass yield than sand dune soil. The burning practice also appeared to affect the elemental concentration of maize shoot. Plants under PLA treatments exhibited higher concentration of nutrients (P, Ca, Mg, K, Mn, Zn and Cu). However, N concentration was higher in PL-treated plants. With increasing application rate, concentrations of elements were substantially increased. Soils after amendment were also analyzed for extractable P using deionized water, Olsen, Bray 1, Mehlich 1 and DTPA extraction procedures. Total P was determined in acid digestion. Except water-soluble P, all extractions released higher P in PLA- than PL-amended soils. The amount of soil P was directly related to the application rate. For litter or litter-treated soils, P extraction methods differed in the order of Mehlich 1 > DTPA > Olsen > Bray 1 > water. Increases in EC and pH of the soils were noted after harvest due to ash application. Phosphorus availability was highly correlated with plant biomass. This experiment signifies the potential use of incinerated PL as P source for crops.