Influence of Soil Properties and Weathering On Fe and Zn Concentrations In Sorghum Grain, Southern Mali, West Africa.

Iron (Fe) and zinc (Zn) deficiencies affect an estimated 3 billion people worldwide and are linked with cognitive and physical impairments, increased maternal and child mortality rates, and decreased adult work activity. In West Africa, anemia rates are particular high. To combat this “hidden” hunger, plant breeders are working to increase Fe and Zn in sorghum grain. Previous research in Mali has shown not only a significant varietal effect, but also a significant environmental effect on grain Fe and Zn concentrations. The objective of this study was to investigate possible environmental factors. In 2009, both soil and sorghum grain samples were collected from participatory variety trials in 4 villages in southern Mali. Soil samples were analyzed for available Fe and Zn, organic carbon, pH, and exchangeable aluminum. Results show increased concentrations of available Zn in soils adjacent to agroforestry trees, especially in soils from mafic parent material. Also, some visibly molded grain had anomalously high Fe concentrations possibly due to the remobilization of Fe to produce reactive oxygen species at the site of pathogen attack. The results of this investigation warrant further study regarding the mold and tree/parent material effects on Fe and Zn concentrations in the grain.