Natural and Entropic Determinants of Soil Carbon Stocks in Two Agro-Ecosystems in Burkina Faso

Impacts of two land-management systems on soil C content and stocks and their dynamic were assessed in two agro-ecosystems of South-West Burkina Faso. The study was carried out on 26 pedological profiles and 112 farmers’ plots for a precise study compared to four plots in a close forest. The study goal was to assess differences between two cropping systems in terms of organic resources management. The itinerant one, based on yam production, developed by the native population and the permanent one based on cotton production, developed by the migrant population. The results show similarities as well as differences: (1) C content and stocks in soil are highly related to textural factors (clay content + tiny silt, %) in both systems; (2) for all uses the average stocks for all plots for the top 20 cm (0–10 and 10–20 cm) of soils are 14 and 12 t C ha–1 and (3) significant differences in C stocks occurred mainly in the 0–10-cm soil layer with higher stocks in the permanent cropping system than in the itinerant system or forest. No significant difference was noticed between cultivated and noncultivated plots. These are the main points of our study. This implies that management factor, as Cultural Intensity (CI) or the position of the plot in the cultural succession (POSISSUC) does not significantly improve C stocks prediction. Similarly texture does not improve C stocks prediction but participates in the variability of C stocks. Lastly, in order to simulate C stocks at the village territory level, taking into account different scenarios including biophysical or socio-economical parameters, the main stock data and equations are to be considered herein. The equations were established for the horizons 0–10 and 10–20 cm for cultivated and noncultivated plots, in permanent and itinerant cropping systems.