The following are reflections from Yushu Xia, a PhD student in the Department of Natural Resources and Environmental Sciences, on her research project partially funded by an ACES International Graduate Grant: “Improving Agricultural Nitrogen Models for Nitrogen Management Assessment at a Field Spatial Scale.” Yushu’s advisor is Dr. Michelle Wander.

“During a two-week stay in France, I had the opportunity to visit multiple labs focusing on a wide range of timely topics in soil research with my advisor, Dr. Wander. As a graduate student working on the modeling of agricultural soil nitrogen losses, I benefited greatly from the experience not only because of the new knowledge I acquired in my specific research field, but also because of the interactions we had with French scientists that made me think about how we should effectively convey our ideas to a broader audience beyond our local soil science community.

Our first stop was a government-funded experimental site in Montoldre where innovative fertilizer spreaders are being developed and modeled to help improve precision agriculture. For my own research project, I have been perplexed by the practicability of varying manure application rate at the field scale in order to improve crop nitrogen use efficiency and reduce nitrogen losses from organically managed systems. Their work shows how, using a fertilizer spreader which models the spatial distribution of fertilizer rates based on the velocity of the machine, might be able to improve applications to avoid unequal or over applications of manure.

The second lab we visited was in Grenoble under the Alps. We visited soil mineralogists who had previously cooperated with our lab to investigate soils from the Morrow plots. After seeing the most up-to-date instruments for measuring soil mineralogy, we discussed how we might enhance our understanding of soil mineral controls of organic matter dynamics using X-ray diffraction spectroscopy.

We then had exciting conversations with professors and graduate students from INRA, which is the equivalent of France’s USDA, regarding long-term studies and micro-scale soil modeling. It was exciting to learn that INRA also maintains a long-term study site like our Morrow plots and that their soil samples were used to test a novel thermal analysis approach that may provide a cost-effective way to delineate labile and recalcitrant soil matter pools. One of the main points I took away is that individual-based models might be needed to improve our understanding of soil carbon and nitrogen cycling processes. That discussion suggested how we might incorporate knowledge about micro-scale controls of denitrification into the estimation of soil nitrogen losses at a larger spatial scale.

This short trip was very effective in that we discussed further cooperation between our lab and French soil scientists. We plan to follow up in a number of ways through sample exchange and the use of novel measurements to investigate and model micro-scale controls of denitrification.”