Land degradation impact on water transfer of soil-plant-atmosphere continuum in the Burkinabe Sahel

This research conducted in the Tougou watershed located in North of Burkina Faso aims at assessing the impact of soil degradation on the water transfer in the soil-plant-atmosphere continuum. Field measurements were performed through an experimental design made of plots measuring 1 m2 each and established on three sites of the watershed: three plots on an erosion crust (PZN), three plots on a desiccation crust supported herbaceous (PZD) and three plots on an area cultivated in sorghum (PZC). Each site was equipped with tensiometric and neutron tubes to measure pressure head and water content of the soil. Results showed that PZN was characterized by a low infiltration capacity enhancing runoff. The water stored during the rain periods is low and remains localized within the first 30 or even 40 cm top of soil, which promoted a quick evaporative recovery in days following the rainy event. PZD and PZC were characterized by a good hydraulic conductivity and a high infiltration speed. The infiltrated water was important and the drainage beyond the depth of 70 cm was observed during important rain events. The real daily average evapotranspiration varied between 3 and 4 mm on the all sites. (Résumé d'auteur