Researchers studied five cocoa systems in Bolivia. These included organic and conventional monocultures, organic and conventional agroforestry, and a successional agroforestry system. The trial ran for 12 years. Organic management raised soil carbon, nitrogen, and pH. It also raised labile carbon content. These gains held across both monoculture and agroforestry.
Biological soil activity followed the same pattern. Soil respiration and nitrogen mineralization peaked in the successional system. Both processes stayed lowest in conventional monoculture. Fungal richness exceeded bacterial richness across all systems. This finding held true throughout the entire trial site. Fungal communities differed by both management type and crop diversity. Bacterial communities differed mainly by management type, not diversity.
Indicator species linked to organic management showed higher taxonomic diversity. Species linked to conventional management showed lower diversity. Crop diversity alone had only a minor effect on microbial communities. Organic monoculture actually outperformed conventional agroforestry on several soil quality measures.
