Carbon storage in Inga-cacao agroforestry on degraded former coca-crop soils

Alegria Zegarra A.S.; Guerra Lu J.K.; Cerna Cueva A.F.; Reategui-Inga M. · Journal of Degraded and Mining Lands Management (2026) · DOI: 10.15243/jdmlm.2026.134.11303

Resumen

Former coca-crop lands in the Peruvian Amazon need restoration that rebuilds soil function and carbon pools. This study compared soil, litter, and recovered-root carbon in degraded former coca-crop soil without agroforestry and Inga edulis-Theobroma cacao systems aged 2, 4, and 6 years. Three blocks provided 12 sampling units of 100 m². Soil carbon stocks (0-20 cm) were calculated from soil organic matter and bulk density; litter and roots were sampled in 0.25 m² quadrats. Block-adjusted analysis and exact within-block tests detected condition effects for all pools after false-discovery-rate adjustment (adjusted p = 0.0069-0.0330). Total carbon was 13.06 ± 2.34 t C ha⁻¹ without agroforestry and 48.06 ± 3.44, 62.62 ± 3.87 and 59.77 ± 5.86 t C ha⁻¹ in the 2-, 4- and 6-year systems, respectively. A parallel first-order compartment model fitted the three pools and derived total carbon as their sum. The derived total curve had R² = 0.921 and a model-implied asymptote of 65.88 t C ha⁻¹; apparent response coefficients were 0.857 yr⁻¹ for soil, 0.387 yr⁻¹ for litter, and 0.242 yr⁻¹ for roots. Agroforestry conditions contained more measured carbon than the non-agroforestry condition, but total carbon did not differ among agroforestry ages. The fitted coefficients describe a cross-sectional condition-age gradient rather than measured annual sequestration. Estimates exclude aboveground biomass and soil below 20 cm. CC BY-NC 4.0 | Attribution-NonCommercial 4.0 International

Instituciones: Universidad Nacional Agraria de la Selva; Universidad Nacional Intercultural de la Selva Central Juan Santos Atahualpa