Each year the KBS LTER awards full and summer fellowships to MSU graduate students. MSU graduate researcher Prakash Jha is a PhD student in Dr. Amor Ines’ lab in the Department of Plant, Soil and Microbial Sciences. He wrote about his 2017 KBS LTER summer fellowship project.
The assessment of agricultural sustainability is complex. On the one hand, the increasing production trends are perceived to be critical to meet the increasing demand of food for the growing population. On the other hand, the excessive use of agricultural inputs to increase food production poses a huge threat to the environment, especially under the uncertainty of a variable and changing climate. Better understanding the dynamics of complex agroecosystems is crucial to achieving the goals of sustainable food systems.
Long-term field experiments have provided data on the dynamics of specific agroecosystems. However, complex cropping systems at larger, field-size scales needs an assessment approach that can detect agroecosystem change and determine the causes of those changes in a more comprehensive way. Remote sensing plays a significant role in this regard. Remote sensing is the observation of features on the ground from aircraft (including drones) or satellites. Crop identification, delineation of crop areas, and making repeated measurements over time are ways in which remote sensing can help us to understand how cropping systems function.
In order to supply crops the water they need, when they need it, many farmers in Southwest Michigan use irrigation. I used my KBS LTER summer fellowship to analyze remote sensing data from SW Michigan to better understand agricultural water management. The study area encompassed eight counties in southwest Michigan. Remote sensing data included net primary productivity, which is the amount of plant biomass produced. Results from remote sensing showed that the total production declined significantly over time. However, surprisingly, when comparing that information with production inventories (non-remote sensing data), I found that most counties showed increased crop yields. Changes in total production can be caused by urbanization, that is, conversion of wetland and forest land into urban land use. In future work, I intend to explore this discrepancy further.
I also modeled evapotranspiration (the sum of evaporation and plant transpiration) across this region over time. This helps us understand how crops are using water over time. To validate the evapotranspiration and soil moisture information we obtained from modeling, I deployed soil water sensors at certain field sites.
As part of my project, we met with an irrigation Extension specialist and farmers at potato fields to better understand the water management practices of farmers. This information coupled with our remote sensing analysis of production and evapotranspiration helped us to better understand the changing cropping systems in southwest Michigan. I presented this preliminary analysis at the annual KBS LTER All Scientist Meeting of KBS-LTER in October 2017 and am also planning to publish these results in a peer-reviewed journal.