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School of Environment and Natural Resources


Graduate Exit Seminar - Christine Charles

Plan to join via Zoom or in person, Christine Charles's graduate exit seminar on March 24, 2022, at 1:00 p.m.  Christine will present, "The Impact of Early Season Drought on Host Millet Physiology and its Microbial Community in a Growth Chamber Study."

Diversified farming systems in which pearl millet (Pennisetum glaucum), is intercropped with an indigenous shrub (Guiera senegalensis) have been shown to increase millet’s resistance to drought in a system known as the Optimized Shrub Intercropping System (OSS) in Senegal. The OSS has been shown to dramatically increase millet yields and to resist drought due to multiple biological, chemical, and physical soil mechanisms. However, plant-microbial relationships in the OSS have not been investigated independently of root hydraulic redistribution of groundwater and the shrub rhizosphere. Therefore, the objective of this research was to determine 1) the influence of OSS cropping and organic matter amendments on soil microbial structure and function during drought and 2) linkages between isolated attributes of the OSS and drought stress responses in pearl millet (Pennisetum glaucum).
Millet aboveground biomass and root system development were significantly improved when grown in intercropped soils. Intercropped soils also were found to have greater enzyme activities and nutrient concentrations than monocropped soils before and after the drought event. Residue amendments also stimulated a more diverse and abundant microbial community before, during, and after drought. It can be concluded that the OSS system has developed soils that aid millet through an early-season drought. Furthermore, the study showed that the pre-season soil amendment of shrub residue provides an additional microbial and nutrient release response that would also assist millet through an early-season drought.

 Advisor: Dr. Richard Dick