Influence of cacao management on tree diversity, carbon stocks and soil properties in the cabruca agroecosystem: a case study in land reform settlements in southern Bahia, Brazil

Abstract Agroforestry systems (AFS) cultivated with cacao ( Theobroma cacao L.) shaded by native or exotic trees offer advantages for biodiversity conservation, carbon storage, and soil and water conservation compared to other agroecosystems. However, management practices can influence the extent of an AFS’s contribution to ecosystem services. In southern Bahia, Brazil, the AFS known as cacao-cabruca involves cultivating cacao under the shade of remnant and regenerating trees from the Atlantic Forest biome. Research and extension projects focused on the agroecological transition were developed in two farming communities, aiming to increase cacao bean productivity through practices that enhance nutrient cycling, biological nitrogen fixation, and soil fertility. We conducted this study to assess the influence of the management system on tree species diversity, carbon stocks, and litter and soil properties in areas of cacao-cabruca AFS under conventional, traditional, and agroecological management in two land reform settlements in southern Bahia. Our results demonstrated that areas under agroecological management had greater species richness. However, there was no significant difference in carbon stocks in the soil, leaf litter, or cacao trees among the three management systems. Regarding carbon stocks in shade trees, agroecological and traditional management did not differ, but both were significantly higher than conventional management. Areas under agroecological management showed higher soil levels of Ca, Mg, and K than those under traditional management, and lower C:N and C:S ratios in the leaf litter than those under conventional management. These findings demonstrate the importance of extension projects for enhancing the ecosystem services associated with AFSs.