General framework for soil and water resource management: Case study of the Fitamaria, Fisakana and Sahanamby sub-watersheds, Amoron'i Mania Region

Water and soil play an important role in agriculture. The geographical context of the research is the Fitamaria, Fisakana and Sahanamby sub-watersheds, in the Fandriana district, Amoron'i Mania Region, Madagascar. Each sub-catchment has these physical and morphometric characteristics: surface area A, compactness index and slope index. A secondary character, such as the overall slope index, and intermediate calculation characters: perimeter P, total vertical drop D, length of equivalent rectangle L, confluence ratio, length ratio and drainage density. At present, GIS can automatically calculate all the morphometric parameters of a sub-catchment, as well as topography and elevation. According to the analysis of various researchers, soils are grouped into different well-defined classes, with solid constituents comprising mineral and organic constituents, and liquid and gaseous constituents.