Impacts des aménagements à courbes de niveaux (ACN) végétalisés ou non sur l’amélioration de la charge en eau du sol dans les Cercles de Koutiala et Yorosso, Mali.

Abstract

In the Sahelian zones, climate change results in insufficient rainfall, which is poorly distributed in time and space, and a decline in soil fertility mainly due to erosion and over-exploitation. This study is based on soil water conservation on plots managed with vegetated or nonvegetated contour bunds. The objective of this study is to measure the improvement of the soil

water recharge

under the management with vegetated bunds or not in the villages of Dionkounda, Kiffosso, M'Pessoba and N'golonianasso in the District of Yorosso and Koutiala, in southern Mali. The soil infiltration measurements were carried out from September to December 2019 using single ring infiltrometer upstream and downstream along the bunds built on contour lines created in August 2015 for the M'Pessoba technology park and in August 2016 for the technological park of N’golonianasso and reinforced with 4 types of vegetation; natural herbaceous vegetation, bursts of strains of Andropogon gayanus a perennial herb and two woody species Gliricidia sepium and Acacia colei. The infiltration rate and the saturated hydraulic conductivity were estimated from the data collected and subjected to statistical analyzes to determine the effects of bunds and type of vegetation on the rate of infiltration of soil water. The results of the analysis revealed a significant difference in the rate of infiltration between the types of vegetation established along the earth bunds constructed along the contour lines. The highest infiltration rate was observed for bunds reinforced with woody species, G. sepium (299.5 ± 3.6 mm / h), followed by A. colei (232.2 ± 2 mm / h), A. gayanus (189.4 ± 2.5 mm / h) and natural herbaceous vegetation (132 ± 2.3 mm / h). The rate of soil water infiltration was higher for the downstream areas compared to upstream for the 2 woody species. These results revealed the positive impact of woody species on improving the soil water rate infiltration compared to A. gayanus and the natural vegetation consisting essentially of annual herbaceous species