South Dakota Vegetable Grower Experiences with Soil Tarping and Solarization during the 2024 Field Season

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).