By Scout Nelson
South Dakota State University (SDSU) has released updated recommendations on soil tarping, a method that helps farmers manage weeds while maintaining soil health. The research offers helpful insights for vegetable growers who want practical and sustainable weed control methods.
The study was conducted by SDSU graduate student Hannah Voye as part of a multi-state research project. The research focused on testing soil tarping as a no-till weed management method and studying its effects on soil health.
Soil tarping involves placing plastic tarps over soil before planting crops. This method helps suppress weeds and prepares a cleaner planting bed for vegetable crops. Voye used onions as a test crop at the specialty crop field on SDSU’s campus in Brookings.
“Our study showed reduced weed pressure, and not a lot of crazy impacts on soil health, which is a positive thing for growers to know,” Voye said. “I think we found a lot of really interesting takeaways for growers interested in using soil tarping.”
The study examined two types of tarps. One method uses opaque tarps that block sunlight from reaching the soil. Without light, weed seeds cannot germinate, which helps farmers plant crops in cleaner soil.
Another method uses clear tarps that trap heat and solar energy. This warms the soil and causes weed seeds to sprout earlier. Since the number of weed seeds in soil is limited, encouraging early growth reduces weed competition later in the growing season.
Researchers also studied the impact of tarping on soil microbes. Many farmers worry that covering soil with plastic could harm beneficial microbes that support healthy soil.
“Many growers were worried about hurting soil microbes on their farms, and this research showed that impacts on soil microbes were very minimal when tarping for 2 to 6 weeks,” Lang said. “If farmers start tarping for months at a time that story may change, but I think this shows that there is a balance that can be found between managing weeds and holding onto soil health.”
Because of South Dakota’s cool spring weather, researchers recommend leaving black or clear tarps on fields for at least 6 weeks to achieve the best results.
The research findings were published in two scientific papers focusing on reduced tillage vegetable production in the Northern Great Plains.
Voye completed her master’s degree in plant science at SDSU and now works with the Ecdysis Foundation, where she continues agricultural research and works directly with farmers. She says her goal is to make research practical and helpful for producers.
“It was a very specific project, and I think tarps are something you can use in a lot of different ways for weed suppression,” Voye said. “I think one of the big things I really grew passionate about working at SDSU as a grad student was wanting to help farmers with our research and having it be directly applicable to them.”
SDSU Extension encourages farmers to explore soil tarping as a useful tool for weed control while protecting soil health.
For more information on horticulture research, visit the SDSU Extension Horticulture Research page or contact Kristine Lang at Kristine.Lang@sdstate.edu, assistant professor and SDSU Extension Consumer Horticulture Specialist.
Photo Credit: istock-nastco
Categories: South Dakota, Crops, Fruits and Vegetables, Sustainable Agriculture