Written by Hannah Voye, SDSU Department of Agronomy, Horticulture and Plant Science Graduate Research Assistant, under the direction and review of Kristine Lang; and Rhoda Burrows, former Professor & SDSU Extension Horticulture Specialist.
Introduction
Occultation and solarization are weed management techniques being explored by vegetable growers across the Midwest and the wider United States (Kubalek, 2022; Rylander, 2020; Birthisel, 2018). Occultation is the use of opaque tarps to block light from reaching weed seeds and seedlings, therefore preventing germination and growth for most weed species. This provides a weed-free growing area at tarp removal without extensive use of tillage or herbicides. Solarization is the use of clear greenhouse plastic, trapping moisture and heat via solar energy and causing a microclimate of elevated moisture and temperature beneath the plastic (Voye, 2023). In high temperature climates, conditions can become so extreme beneath the plastic that weed seeds and seedlings in the soil die. In cooler climates, temperatures can become warm enough to germinate weed seeds and enhance weed growth earlier in the season than is common, exhausting the weed seed bank. In this case, a grower will need to terminate weeds before planting into the area.
On-farm research trials in South Dakota aimed to understand how a grower can realistically use tarps for reducing weed competition in their specific system as well as to increase grower’s knowledge of this tool. This research was an extension of on-campus research in Brookings, SD studying the effects of tarp material and time on weed pressure and crop growth (Voye, 2024; Voye, 2025).
Acknowledgements
This material is based upon work that is supported by the National Institute of Food and Agriculture, U.S. Department of Agriculture, under agreement number 2022-38640-37486 through the North Central Region SARE program under project number LNC22-460. USDA is an equal opportunity employer and service provider. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture. Special thank you to Travis Iverson and team at West River Research Farm as well as Lang Lab Graduate and Undergraduate Research Assistants at South Dakota State University: MacKenzie Christopher, Kenadie Fick, Ellen Fitzpatrick, Emily Guggisberg, Tayah McGregor, Kristina Harms, Gabrielle Thooft, Abdulrahman Hassanien, Connor Ruen and Trevor Ruen.
