Optimising pH of layer and broiler litter of contrasting bedding materials through co-composting with wood ash and effect on co-compost quality

Abstract

This study investigated whether co-composting chicken litter with wood ash could raise its pH to match agricultural lime’s liming potential, since chicken litter’s naturally low pH limits its capacity for correcting acidic tropical soils. Layer and broiler litter with coffee husks or wood shavings as bedding material, where 5 kg samples were combined with wood ash at the rates of 0.5, 1.0, 2.0, and 4.0 kg and co-composted for one-month to determine the minimum ash amount needed to raise the co-compost pH to the agricultural lime range (9–12), and assess the effect on co-compost quality. Layer litter with coffee husk bedding (LCH) needed the least wood ash, 0.85 kg per 5 kg of litter to optimise pH to 9.9 ± 0.1 whereas broiler litter with the same bedding (BCH) needed the largest, 1.83 kg wood ash, to attain optimum pH of 9.8 ± 0.1. Moreover, high Fe, Mn, and EC originally present in the litter and ash substrates were suppressed to acceptable levels in the co-composts. All co-composts had low C:N ratios, and coffee husk co-composts had excessive Mn, which can lead to nitrogen loss through leaching and phytotoxicity, respectively. Coffee husks are better bedding choice for layers but wood shavings for broilers for production of co-composts of superior liming potential and fertiliser quality.