AMES, Iowa (Sept. 9, 2026) — Wet weather can keep farmers out of their fields, putting pressure on already-tight planting and fieldwork windows. Those windows are getting smaller. Since 1964, Iowa has lost about one suitable spring fieldwork day every six years.
“For years, we’ve heard farmers tell us that cover crops are helping them get into their fields earlier in the spring and get through harvest without leaving ruts,” says Stefan Gailans, PFI’s research director. “We wanted to take a closer look and see if the data backs that up.”
In 2025, 38 farmers across Iowa, Minnesota, Nebraska and Wisconsin tracked whether they could work fields with a history of cover crop use each week from spring through fall. Farmers recorded whether field and weather conditions allowed them to work their fields for most of the day.
PFI compared those observations with USDA estimates, using the same definition of a suitable fieldwork day.
The findings
Overall, PFI farmers reported about the same number of days suitable for fieldwork as the USDA average in 2025.
PFI farmers reported 51 suitable spring fieldwork days, one more than the USDA average. They reported 51 days in summer, matching the USDA average, and 27 days in fall, one fewer than the USDA average. Altogether, farmers reported, on average, 129 suitable fieldwork days, matching the USDA average.
While PFI farmers reported results similar to the USDA average, some fields with long-term cover crop use showed different results.
Margaret Hogan of Earlville, Iowa, reported 157 days when she could work her fields from April through November, compared with 127 days for her USDA district over the same period. In the spring, she reported 67 days suitable for fieldwork, compared with 46 days for the USDA district average. She has used cover crops for more than 10 years.
“The most valuable aspect of conducting this trial for me is being able to show others another reason to use cover crops,” Margaret says.
PFI started the study with 15 farmers in 2024 and grew to 38 farmers in 2025. The study will continue with farmers across the Midwest as PFI gathers more information to see whether the results stay the same from year to year and in different weather conditions.
To explore the full findings, visit practicalfarmers.org/do-cover-crops-increase-the-number-of-days-suitable-for-field-work-2025.
Farmers interested in participating in future trials can contact Stefan Gailans at stefan.gailans@
