Processing and Storage Effects on the Concentration of Water-Soluble Phosphorus and Trace Nutrients

Background and Objective: High cost of mineral fertilizers has resulted in increased use of animal manure by smallholder farmers in Nigeria. A study was carried out to process manure as practised by farmers to assess the effect on nutrient concentration as well as water-soluble P. Materials and Methods: Four manure types, poultry litter, cow dung, sheep and goat and farmyard manure were used in the research. The different manures were subjected to three treatments, shade drying, sun drying and composting. The materials were sampled at one, two and three-month intervals and analyzed for the amount of water-soluble phosphorus, calcium, magnesium and some micronutrients. Data were subjected to analyses of variance. Results: The results showed significant differences (p<0.05) in the amount of WSP by sources, processing and storage with the lowest amount of WSP obtained from poultry manure (2162.26 mg kg^-1). Sun drying and long storage duration (3 months) were observed to have the lowest WSP concentration of 2009.54 and 2109.95 mg kg^-1, respectively. High contents of Ca and micronutrients were observed with composting. Conclusion: The results obtained showed that processing and storage of manure plays a significant role in the efficiency of nutrient retention and sun drying of manures could serve as a method to reduce the loss of water soluble phosphorous.