Classificação da capacidade de uso e planejamento conservacionista do solo na região sul do Mali: estudo de caso nas aldeias agrícolas de Siani e Bandiagara II

Abstract

On the African continent, about 27% of soils are found in a state of moderate to high degradation, with 65% of them used for agricultural purposes. Agriculture is an important economic activity of Mali and cotton is its main export crop. However, many of the country's farms face serious soil degradation problems, mainly due to water erosion and low fertility. The land use capability classification system is a methodology orientated towards soil conservation and establishes its best use within the concepts of agroecosystems sustainability. The main objective of this study was to propose a land use capability classification adapted to the conditions of low-tech farms in the agricultural villages of Siani and Bandiagara II in Mali, West Africa, using remote sensing methodologies. Thus, a survey and characterization of the physical environment, field observations, pedological surveys, field tests and physical and chemical soil analyses were carried out. High-resolution orthomosaics and a Digital Terrain Model (DTM) were also generated from aerial images obtained with a digital camera on-board an Unmanned Aerial Vehicle (UAV) using digital aerophotogrammetry techniques. Based on the dataset generated, the diagnostic criteria selected for the general and specific limiting factors proved to be suitable for characterizing both areas and, consequently, classifying their land use capability. Limiting factors related to soil fertility (CTC, V and MOS), climate (water regime), water availability (drainage and water deficit) and soil (crusting degree) were added to the adapted method. In both villages, the land use capability classes IVs,c, IVe,s,c and VIe were determined. The method adapted to the conditions of the Malinese villages proved to be the most flexible of the methods applied. Finally, a recommendation was made for conservation land use planning, allowing the implementation of Technical Demonstration Units (TDU), in order to guarantee the sustainability of the agroecosystems studied and the dissemination of conservation techniques in different regions of West Africa.