Researchers tested five cacao cropping systems in Bolivia. These included conventional and organic monocultures, conventional and organic agroforestry, and successional agroforestry. They buried litterbags filled with cacao leaves and leaf mixtures. The bags used two mesh sizes: 0.1 mm and 2 mm. The team collected samples at 4, 8, and 12 months.
Decomposition was fast across all systems. Litter lost over 40% of its carbon within 4 months. By 12 months, carbon losses exceeded 80%, and nearly all phosphorus and potassium were gone. Cropping system had limited effects. Nitrogen content rose only under conventional agroforestry, and only at 4 months. Phosphorus stayed higher under agroforestry than monocultures, but only at 8 months. No other differences appeared between systems.
Mesh size mattered more than cropping system. Larger-mesh bags lost more carbon, nitrogen, phosphorus, and potassium than smaller-mesh bags in early months. This points to microbial colonization and leaching, not soil animals, as the main drivers. Leaf mixture type also shaped decomposition. Bags with diverse shade-tree leaves (M2) held more carbon and nitrogen than cacao-only bags. But bags dominated by cacao leaves (M1) showed no such difference.
Finally, the team estimated nutrient supply from pruning residues. These residues can cover most of cacao’s yearly nitrogen needs. They meet only 5–35% of its phosphorus needs.
