CHARACTERIZATION OF THE TEXTURE AND USABLE WATER RESERVES OF SOILS AROUND THE LOWLANDS IN THE MUNICIPALITY OF REO (BURKINA FASO)

Soil is generally composed of clay, silt, and sand. Soil texture is therefore the relative proportion of these different grain sizes in a horizon. It is an indicator of the physical and chemical fertility of the soil. The objective of this study is to determine the texture classes and useful water reserves of soils for agriculture around the lowlands in the municipality of Reo. The methodology is based on documentary research, soil sampling followed by laboratory analysis, and data processing. Soil samples are analyzed in the laboratory using the hydrometric method for three-fraction grain size analysis and the pressure chamber method for available water reserve analysis. The results show that the silty-sandy texture is the most representative and covers 37% of the total area of the study zone. It is followed by clayey texture (36%) and silty-clayey texture (20%). This textural composition influences the soil's usable water reserve. Thus, silty-sandy soils (leached tropical ferruginous soils) on glacis have low usable water reserves (between 3 and 9%). On the other hand, clay soils (tropical eutrophic brown soils), located in the depression and lowlands, are well drained, with high useful reserves (between 13.10 and 23.60%). Ultimately, the soils around the Goundi-Djoro lowlands have textural and water properties that are not very favorable for agriculture. Farmers should make sufficient use of organic matter, as it improves soil texture, increases its water retention capacity, and mitigates the effects of water erosion.