This article, by Kally Arnzen, is part of a series highlighting members of the Office of Sustainability’s Experts Database. In a collaboration with instructor Hannah Monroe’s course, LSC 561: Writing Science for the Public, students interviewed campus sustainability experts and produced short feature stories.
As a native Midwesterner, Anita Thompson recalls that her childhood winters in Minnesota followed a reliable pattern of the ground freezing and thawing at roughly the same times every winter and spring. Over the years, these weather patterns have changed rapidly and become far less
consistent.
“What that means in the wintertime is that the soil conditions and the amount of ice that’s in the soil and how nutrients are responding to that are changing,” Thompson explained.
Thompson’s lab at the University of Wisconsin–Madison’s Nelson Institute for Environmental Studies aims to understand how changes in these processes impact the quantity and quality of water resources. The lab also seeks ways to reduce the impact of inconsistent weather patterns on groundwater and surface water systems.
Both agricultural and urban environments benefit from this approach, called predictive watershed modeling, because it helps inform decisions on land management practices that preserve water resources, water quantity, and water quality in a way that provides for the needs of society today without sacrificing the needs of future generations.
Specifically, Thompson’s lab investigates how wintertime hydrological processes influence the moisture content, physical properties, and nutrient migration of soil in agricultural settings. These water processes include snow cover and freeze-thaw cycling, which is the pattern of groundwater freezing solid and re-thawing to liquid water within the soil. In turn, these processes affect how nutrients contained within the soil migrate to both underground and surface water systems and affect the quantity and quality of the water found in them. In urban environments, Thompson’s lab is interested in how stormwater management and urban water management practices can further affect water quality.
Wintertime hydrological processes are far less studied than the typical agricultural growing season, creating a knowledge gap that leads to less physical representation within watershed models and, as Thompson notes, “that leads to errors in predication and that can lead to misunderstanding in what conservation or best management practices might be most effective throughout a watershed.”
Thompson hopes to bridge the research gap and help inform land management decisions that enable practices which reduce runoff, soil erosion, and nutrient loss.
There is “not a one-size-fits-all in terms of what’s good and will work throughout the whole annual cycle,” she said. Rather, both winter and growing seasons must be considered, depending on when the landscape is most vulnerable to losses in soil and water quality.
Progressions of changing weather patterns also play an important role in watershed models’ predicative capabilities, as they can be used to compare, contrast, and predict weather between regions. Often, the current climate in one region is a perfect example of what the climate in a nearby region may look like in coming years as climate trends change.
To physically address these questions, soil samples are taken from across different scales — from small, temperature-controlled laboratory soil samples to larger in-field samples from working farms. The soil samples are then used to model wintertime processes in various physical watershed models, which represent a system of water for a given area. With these samples, the Thompson lab can test the effects of the various conditions mentioned from agricultural and urban perspectives, different climates, and different water management strategies.
Thompson’s lab collaborates with researchers far and wide, from Midwestern neighbors of Minnesota and Ohio to vastly different climates and landscapes in Alaska and Texas, to create a larger frame of reference and enhance predictability for effective water and soil management. In time, Thompson hopes to connect with researchers to create a global network dedicated to improving soil and land management practices.
Understanding these processes and forming a basis for physical predictions can help policy makers and producers prepare for what future changes to the landscape will mean for the water quality in that region. Thompson hopes that by implementing better conversation and management practices, agriculture can become more sustainable and a part of the solution to climate change, thinking of the future, while still providing for the needs of people today.