By Hannah Francis, PhD student in the Ruark Lab,
UW-Madison Department of Soil Science
Repeated torrential rainstorms do not make soil sampling easy. Yet here we were in late June at the UW-Arlington Agricultural Research Station assessing the field from its edge, deciding how to move forward with a project.
“The field is flooded in the 300 block,” the field technician Tom Bodden had reported to the team.
We were there to set up a field experiment – applying different fertilizer rates with and without manure application, and with and without a cover crop. Tom rubbed the back of his neck during another hot and humid summer day.
“Just skip the blocks that are underwater; we’ll come back to them later,” he said.
I was just a few months into the start of a PhD program in Soil Science. This project – “Corn silage nitrogen response following manure and cover crops” – was my springboard into ag research. We’re looking at a system with or without cover crops, with or without manure, and determining differences with nitrogen application rates and in yield with corn grain and corn silage.
Heavy rains fell on an experimental farm-research plot in Arlington, Wisconsin.
In a summer with wide temperature swings and days of heavy rain, research has demanded we investigate resilient agricultural systems. In our project, we’re looking at sustainable intensification, employing many of the soil-health principles to inform future practices in existing rotations. This project touches on all five of the major soil health principles.
1. Minimize Soil Disturbance
2. Maximize Presence of Living Roots
3. Maximize Soil Cover
4. Maximize Biodiversity
5. Integrate Livestock into Cropping Systems
The entire project is in a no-till system, meaning we are not employing tillage for weed control. This minimizes soil disturbance and preserves soil structure.
Some of the treatments had cereal rye as a cover crop planted after the corn. Cover crops maximize the presence of living roots by growing from the fall through the winter before termination the following spring. They also maximize soil cover during growth and protect the soil from erosion. This helps retain nutrients and, in this instance, we’re particularly focused on nitrogen, a nutrient that is relatively mobile through the soil. It can enter our waterways in excess, contributing to eutrophication.
Incorporating cover crops also is a way to introduce biodiversity to a farm field since it is a different species planted between the main cash crops.
And, by understanding the implications of manure incorporation and effects on silage yield, we’re accounting for the integration of livestock into cropping systems.
The advantages of cover cropping on the landscape are well known in agricultural studies, but there are always more questions. Among other agroecosystem services, we know that cover crops can help farmers manage nutrient dynamics, but what does timing of nutrient release look like? Where are those nutrients going when cover crops are terminated and begin to decay? Can we use soil chemistry and soil-health indicators to help answer these questions?
I’m interested in exploring these questions as I dive into PhD work. Despite the wet weather, we did get the parts of the manure and cover crop study all set up, with some modifications (as always happens when science happens in dynamic systems).
Stay tuned for updates on this project and new projects to come!
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