Posted: July 6, 2018
Congratulations to Dr. Graham Jeffries, who received his doctoral degree in Agriculture, Food and Environment from the Friedman School of Nutrition Science and Policy at Tufts University earlier this year. While pursuing his master’s degree at Tufts, Jeffries was a student member of the EFSNE project, working with Tim Griffin who co-leads the Production Team.
Jeffries contributed his geospatial data analysis skills to several Production Team efforts related to mapping the spatial distribution of crops and the variability of crop yields. He completed two research internships with Production Team members: one with Michael Conard at Columbia University where he studied the contribution of urban and peri-urban agriculture to regional food production, and another with David Fleisher at USDA Agricultural Research Service studying how yield estimates from crop models may be affected by the quality of weather datasets used as model inputs.
For his dissertation research, Jeffries explored the extent to which satellite imagery can be used to measure and map crop yields. Using remote-sensing imagery along with socio-environmental datasets and a mixture of biophysical and statistical modeling tools, he developed methods for high-resolution mapping of corn yields in Nebraska to support farm management planning. In another dissertation chapter, he predicted Brazilian soybean yields with satellite imagery in order to quantify how yield gaps (potential yield minus actual yield) vary with respect to farm size and cropping intensity. His findings suggest that remote sensing is likely to play an important role in identifying pathways to higher yielding and more resilient cropping systems in the future.
Jeffries' dissertation committee, which was chaired by Griffin, also included Fleisher.
Jeffries successfully defended his dissertation in January and has since joined Griffin's lab as a postdoctoral scholar. His postdoctoral work leverages geospatial big data to estimate the effect of climate variability on soybean planting dates and productivity in central Brazil.
Congratulations, Graham!
