Phosphorus release from poultry litter to the soil due to the management

The study aimed to evaluate phosphorus release (P) from poultry litter (composted and uncomposted poultry litter) to the soil under different pH and depth conditions of application in typical Red Distroferric Oxisolin the city of Toledo, western Parana state. The experiment was conducted under field conditions, in a randomized block design with treatments arranged in a 2x2x3 factorial scheme, consisting of two soil pH adjustments (5.5 and 6.0), two types of poultry litter (composted and uncomposted), and three different application depths (0, 0.05 and 0.10 m), with four replications. Regarding the assessment, P levels were determined from soil samples collected at the time of experiment implementation, followed by three other collections with 15days intervals. The largest P release into the soil at all depths of application and types of poultry litter was observed at pH 6.0 respect of pH 5.5. The application of uncomposted poultry litter onto the surface under pH 6.0 and during 45 days of evaluation released more P 45 days after application, followed by those at depths of 0.05 and 0.10 m. Uncomposted poultry litter was more efficient that composted in providing P, as evaluated by Mehlich-1 extractor.   Key words: Decomposition, organic fertilizer, nutrient availability.