Chelsea Delay's Graduate Defense Seminar

A Graduate Defense Seminar will be presented by Chelsea Delay, MS candidate in Soil Science. She will present Nitrogen Dynamics and enzymatic Activities of Shrub-millet Systems in Senegal in 333 Kottman Hall.

Rapid population growth observed in sub-Saharan Africa has caused many concerns over food security in the region. In particular, the semi-arid environment of the Sahel, along with inherently low quality soils, has made food production very difficult. However, two native shrubs, Guiera senegalensis and Piliostigma reticulatum, are known to increase yields when intercropped with millet and peanut. Both shrubs are capable of performing hydraulic redistribution, the movement of water through tap roots to surface roots. The improved water relations associated with the shrub systems, along with the increase in nutrients from shrub litter, root exudates, and root turnover, are thought to have positive impacts on microbial communities. However, little research has been done concerning the microbial communities associated with the shrub rhizopsheres. A central objective of this study was to determine the effects the shrubs have on soil enzyme activities across a rainfall regime in the Peanut Basin of Senegal. Furthermore, the ability of the shrubs to stimulate biological N fixation was also investigated. Results from both experiments provide further evidence that these shrub systems have significant impacts on microbial actjvjty and biogeochemical processes that can lead to higher agricultural productivity.

Dr. Richard Dick, advisor