Growth and Yield Response of Mucuna pruriens Plants to Soil Moisture Variation in the Cotton Belt of Mali, West Africa

Livestock farming in the cotton belt of Mali faces many challenges, including forage constraints. The forage stock that is built up at the end of the growing season is no longer sufficient to meet the livestock feed requirements due to the increase in livestock numbers and the expansion of farmland, which considerably reduces the rangelands. Forage crops, particularly Mucuna pruriens, could help reduce the vulnerability of livestock production systems in the cotton belt of Mali to seasonal fodder shortages. This study aims to better understand the variations in Mucuna pruriens production in response to rainfall variability and, consequently, soil moisture. Hemispherical photographs of pure Mucuna pruriens plants in parallel with soil moisture measurements. These measurements were taken in 9 plots of 25 m x 25 m (3/site) at Sotuba, Béguéné, and Ziguéna. The data, including leaf area index data (LAI) estimated by remote sensing and Hemispherical photographs, and soil moisture, were also used to monitor the seasonal dynamics of biomass and water use. This study showed that the yield of Mucuna pruriens is only weakly correlated with the annual rainfall. Dry sequences of 3 days were in the majority at all three sites, representing up to 79%, 76%, and 78% of the total recorded at Sotuba, Béguéné, and Ziguéna, respectively, during the same year. In contrast, those longer than 10 days represented only 4%, 11%, and 10% of the total in Sotuba, Béguéné, and Ziguéna, respectively. The linear regression between the average soil moisture (120 days after sowing) at each site and the maximum leaf area index explains 41% of this variability.