SDSU issues new soil tarping guidelines

South Dakota State University released updated soil tarping guidelines to help vegetable growers manage weeds while protecting soil health. New research shows that using black or clear tarps for several weeks can reduce weed pressure with minimal impact on soil conditions.

South Dakota State University (SDSU) has released revised guidance on soil tarping, a method designed to aid vegetable producers in controlling weed growth while supporting soil health. The updated recommendations are based on recent research led by graduate student Hannah Voye, who collaborated with a multi-state research team to evaluate the effectiveness of soil tarping within reduced tillage vegetable systems.

Research Methodology and Key Findings

The SDSU study investigated the use of tarps on soil prior to planting vegetable crops, with a focus on onions, to assess their impact on both weed suppression and soil conditions. The research revealed that tarping significantly reduces weed pressure while maintaining soil health. Voye noted that the research indicated minimal negative effects on the soil, highlighting the potential benefits for growers.

Two types of tarps were tested during the study:

• Opaque Tarps: These block sunlight from reaching the soil, preventing weed seeds from germinating and creating a relatively weed-free environment for planting.
• Clear Tarps: These use solar heat to warm the soil, triggering early weed seed germination. This early germination depletes the weed seed bank, reducing competition with crops later in the growing season.

The research demonstrated that even under South Dakota’s cooler spring conditions, using black or clear tarps for a minimum of six weeks is effective for managing weeds in vegetable crops.

Soil Health and Microbial Activity

Farmers have expressed concerns regarding the potential impact of tarping on soil microbial communities. Research conducted by SDSU, under the guidance of Voye and assistant professor Kristine Lang, indicates that short-term tarping of up to six weeks has minimal effects on soil microbial activity. Lang stated that extended tarping periods could change these outcomes, but the study confirms that it is possible to manage weeds while preserving soil health.

Research Publications and Recognition

The study’s findings have been documented in two scientific publications:

• Improving Reduced Tillage Vegetable Systems for the Northern Great Plains: How Does Early Season Soil Tarping (Solarization and Occultation) Impact Soil Health?
• Improving Reduced Tillage in Northern Great Plains Onion Production through Early Season Soil Tarping

Lang commended Voye for her detailed research and her collaboration with local farmers. The project included practical considerations such as calculating the number of sandbags needed to secure tarps and collecting soil samples to evaluate microbial activity in laboratory settings. Voye acknowledged the guidance of her co-advisers, Lang and retired SDSU Extension Horticulture Specialist Rhoda Burrows, throughout the research and publication process.

Practical Applications for Producers

Voye emphasized that soil tarping is a versatile tool for weed management in vegetable production. The research provides actionable recommendations for growers interested in integrating tarping into their crop management strategies while minimizing risks to soil health.

Graduate Research and Professional Development

Hannah Voye, originally from Wisconsin, earned a master’s degree in plant science from SDSU in May, after completing a bachelor’s degree in horticulture from the University of Wisconsin-River Falls. She currently works at the Ecdysis Foundation in Estelline, conducting applied research across farms in the United States. Voye noted that her graduate experience at SDSU strengthened her interest in research with practical applications for farmers.

Lang highlighted Voye’s dedication, adaptability, and ability to balance fieldwork with laboratory analysis as key factors contributing to the project’s success. SDSU Extension engages graduate students in outreach, enabling them to share research findings with farmers and at national conferences.

Additional Information

For further details on horticulture research at SDSU, visit the SDSU Extension Horticulture Research page or contact Kristine Lang, assistant professor and SDSU Extension Consumer Horticulture Specialist.

Sources:

• SDSU provides updated recommendations on soil tarping
• SDSU Research Explains Benefits of Soil Tarping
• SDSU Provides Updated Recommendations on Soil Tarping (Farms.com)

Author: Grace Ellison
Grace Ellison is a journalist focusing on environmental issues and sustainability. She has experience publishing international reports and participating in documentary projects.