Julien Avakoudjo

To restore soils degraded by unsuitable practices, which have led to declines in organic matter content and associated consequences, sustainable land management (SLM) practices have been implemented in central Benin. This study aimed to evaluate the effects of these practices on soil organic matter (SOM) levels in cultivated soils in Central Benin. Soil samples were collected from a depth of 0 to 20 cm on SLM plots in two agricultural areas: N’Tchon and Odjobilè. The SLM practices studied were maize intercropped with pigeon pea ( Cajanus cajan ), mucuna ( Mucuna pruriens ), soybean ( Glycine max ), cowpea ( Vigna unguiculata ), groundnut ( Arachis hypogea ), aeschynomene ( Aeschynomene histrix ), and cassava ( Manihot esculenta ). For each SLM practice, adjacent control plots were sampled. Soil pH, cation exchange capacity (CEC), soil organic carbon (SOC), carbon organic stock (COS), and particulate organic carbon (POC) were measured. Compared to the adjacent control plots, the soybean–maize and aeschynomene–maize rotations significantly increased soil CEC ( p < 0.05). SOC differed significantly ( p < 0.05) among SLM practices, ranging from 0.37 to 1.67 g/kg. COS was higher with pigeon pea–maize intercropping (37.21 Mg C ha ⁻¹ ) in Odjobilè and with cassava–maize intercropping (37.46 Mg C ha ⁻¹ ) in N’Tchon. The contribution of coarse particulate organic carbon (cPOM‐C) to total particulate organic carbon (tPOM‐C) was smaller than that of fine particulate organic carbon. The greatest cPOM‐C was observed with cowpea–maize and pigeon pea–maize intercropping. However, the greatest fPOM‐C was observed with cowpea–maize intercropping in Odjobilè and with pigeon pea–maize intercropping in N’Tchon. Therefore, SLM practices, such as intercropping with pigeon peas and maize, can serve as an alternative to crop residue burning. These practices can help restore the fertility of degraded soils.