Enriched cocoa pod composts and their fertilizing effects on hybrid cocoa seedlings

Purpose Composting has the potential to recycle wastes asa means of conserving natural resources. The study wasaimed at examining feasibility of producing nutrient-enrichedcomposts from pest infested cocoa pods withchemical amendments and using manure composts as afertilizing material in cocoa seedling nursery.Methods Cocoa pod waste was composted in static vessels,aerobically, with chemical enrichments (triple superphosphate charged at 0.4% P or urea charged at 0.8% N orpoultry manure charged at 22%) along with a control at theCocoa and Coconut Institute, Papua New Guinea. Thereaction (pH) of the composting mixtures (pH) and macronutrientsdynamics was monitored at periodic intervals.Effect of soil incorporation of cocoa pod manure compostsat 10 g kg-1 was assessed on the growth and foliar concentrationof macro-nutrients in hybrid cocoa seedlings.Results In the finished manure composts, dry matter lossranged from 30.6 to 63.3%; greatest in composting mixturescharged with super phosphate and poultry manure.Besides, super phosphate enriched mixture lost smallfraction of initial N (6.6%) compared to un-enriched cocoapod waste (30.2%). Composting mixtures with greater pHvalues during composting process showed higher losses ofN. Super phosphate charged manure compost outperformedthe control, in terms of C/N ratio and concentration ofmacro-nutrients (P, K, Ca, Mg and S). Quality parametersfor all the manure composts conformed to the CanadianCompost Guidelines indicating satisfactory standards.Waste cocoa pods enriched with superphosphate did notshow any deleterious effects on cocoa seedlings’ growth,rather, improved plant height, dry matter production andfoliar N concentration.Conclusion Waste cocoa pods, co-composted with triplesuper phosphate and poultry manure, produced composts ofdesirable quality and can be effectively used to fertilize thecocoa seedlings.