Spatial Assessment of Soil Degradation in the Western Cotton-Growing Zone of Burkina Faso

Résumé fourni par la source

This study assesses the extent of soil degradation in the western cotton-farming region of Burkina Faso, aiming to provide essential insights to support sustainable land management efforts and to guide future research on soil fertility restoration strategies. A total of 32 soil samples were collected along a transect designed according to the physiographic units and land use: protected forests, croplands, and pasturelands. Soil physico-chemical analyses were conducted to determine Organic Matter content (OM), Cation Exchange Capacity (CEC), total nitrogen (N), available phosphorus (P), exchangeable potassium (K), acidity (pHH2O) and soil texture. Spatial distribution of these parameters was mapped using the Inverse Distance Weighted (IDW) interpolation method. Additionally, soil degradation was assessed with a synthetic Soil Degradation Index (SDI). The impact of land use patterns and topography on soil fertility was analysed through the SDI and linear regression, respectively. Results indicate that over 95% of soils had OM levels below 2% and CEC values were predominantly low to very low. Moreover, more than 55% of soils were strongly acidic and nutrient levels were low in over 70% of soils. Soil texture was dominated by sandy fractions, ranging from 27% to 80%, showing a positive correlation with slope. In ferruginous soils located on steep slopes, degradation levels ranged from moderate (81% of the soils) to severe (19%). In croplands and pasturelands, key soil parameters, such as C, N, K and CEC, were approximately 20% lower than in forest lands, although there was a slight increase in sand and P content. This finding highlights the alarming degradation of soil under agricultural and grazing pressure and emphasizes the urgent need for sustainable soil fertility management strategies to preserve and enhance soil productivity.

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