Exploring the Efficacy of Robotic Weeders on Vermont Farms

Commodities

• Agronomic: corn, soybeans

Practices

• Education and Training: on-farm/ranch research
• Pest Management: physical control, weed ecology

Weeds are a perennial problem in Vermont row-crop fields, reducing yields and forcing reliance on herbicides that can lead to herbicide resistance, water pollution, and high costs. Vermont's total corn and soybean acreage totaled approximately 90,000 acres in 2022, driven by demand for dairy feed. Dairy remains Vermont's largest agricultural sector ($529 million in 2024). Effective, low-impact weed management is therefore critical.

Greenfield Robotics WeedBots are autonomous, battery-powered machines that mechanically mow weeds between crop rows without disturbing soil or using chemicals. They have shown promise in the Midwest but have never been tested in the Northeast's heavy clay soils, steep slopes, rocks, and frequent rain. This project will be the first rigorous on-farm evaluation of WeedBots in Vermont.

We will conduct replicated field trials at two working farms in Alburgh, Vermont-Borderview Research Farm (Roger Rainville) and Henry Bros. Farm (Brenden Henry)-comparing WeedBots to standard practices used by both organic and conventional growers: inter-row mowing, inter-row cultivation, herbicide (with and without tillage), and a no-management control. Soybeans will be planted at 180,000 seeds/acre in 30-inch rows and corn will be planted at 32,000 seeds/acre in 30-inch rows. Data collected will include weed and crop biomass, crop yield and quality, input costs, labor time, and implementation feasibility.

By partnering directly with two experienced farmers, the project ensures real-world relevance and immediate adoption potential. Findings will be disseminated through a field day, webinar, and on-farm demonstrations to growers, agronomists, and Extension professionals across Vermont and the Northeast. This work directly supports Northeast SARE's legislative priorities by conserving soil and water, reducing pesticide use, and maintaining farm profitability.

1. Determine whether Greenfield Robotics WeedBots provide effective weed control in Vermont corn silage and soybean fields compared with standard inter-row cultivation and herbicide programs used by organic and conventional dairy farmers.
2. Quantify the impacts of WeedBots on herbicide use, input costs, labor requirements, crop yield, and forage/grain quality to assess their potential for improving farm viability while reducing chemical reliance.
3. Disseminate practical, on-farm results to Vermont and Northeast dairy growers, agronomists, and Extension professionals through targeted outreach so that farmers can make informed decisions about adopting autonomous mechanical weed management to meet water quality regulations and maintain profitable corn and soybean production for dairy feed.

These objectives directly address the growing challenge of herbicide resistance, tightening environmental regulations (including Vermont's Required Agricultural Practices and Lake Champlain TMDL), and the need for cost-effective, lower-chemical weed control options that support long-term economic viability and environmental stewardship on Northeast dairy farms.