Chemical Characterization and Stability of Poultry Manure Tea and Its Influence on Phosphorus Sorption Indices of Tropical Soils

This study characterized poultry manure extract (tea) and investigated the effects of integrated use of tea and the sequence of phosphorus (P) application [P added before (PBT), after (TBP), or jointly (PT) with tea] on P-sorption characteristics on acidic, alkaline, and neutral tropical soils. Results indicated that diluted tea contained 400 mg nitrogen, 155.80 mg potassium, and 10.48 mg P L−1 and the nutrients were greatest after 2 weeks. Soil P sorption conformed to the Freundlich model, indicating that soil P affinity was less than the aqueous solution at low solution P concentration. Freundlich index (k) in neutral soil was 78 and 94% greater than in acidic and alkaline soils, respectively. The lowest P sorption efficiency and greatest phosphate requirement were in acidic soil. Poultry manure tea could enhance P availability and reduce P fixation irrespective of the sequence of application of tea and P.