Project Overview

Reports

Commodities

• Agronomic: corn, cover crops, rye, soybeans

• Ecosystem: Ecosystem

Target Pests

Practices

• Pest Management: allelopathy, chemical control, cultural control, decision support system, pesticide resistance management, weed ecology

• Crop Production: cover crops, cropping systems, no-till

• Production Systems: agroecosystems

A) Problem / Opportunity: Farmers across the U.S. Midwest are planting soybeans earlier to take advantage of longer growing seasons. At the same time, they are fighting waterhemp, an aggressive weed that produces huge numbers of seeds, emerges over a long period, and has evolved resistance to many common herbicides. With soybeans grown on more than 86 million acres in the U.S., much of that in the North Central region, and weed management achieved primarily with herbicides, improving waterhemp management is both an agronomic and environmental priority. Growers are already experimenting with three promising cultural weed management tactics: planting soybeans earlier, narrow soybean row spacing, and adopting cover crops. However, these practices are usually evaluated in isolation. The combined system, early planting plus narrow row and planting green into cereal rye, has not been systematically investigated across multiple locations. This creates a major knowledge gap, where farmers want to know whether this highly integrated approach truly suppresses waterhemp, optimizes yield, and can fit within their weed-crop management programs.

B) Approach: This project will evaluate a range of soybean management practices, comparing conventional approaches (tillage, no cereal rye, wider rows, later planting) with integrated practices that stack no-till management, earlier planting, narrower soybean rows,  and cereal rye cover crop. Both practice sets will be paired with a standard PRE followed by POST herbicide program so that the added value of the integrated tactics can be quantified.

C) Project Objectives. Research trials will be conducted in Wisconsin and Indiana for a total of 3 locations in 2026. In simple terms, we will:

• Plant cereal rye in the fall ahead of soybeans, let it grow, and then “plant green” by seeding soybeans into the living rye before terminating it.
• Adjust soybean planting dates and row spacing to see how quickly the crop can close its canopy and shade out waterhemp.
• Measure waterhemp density, biomass, and seed production, along with soybean stand, canopy development, and yield.

A graduate research assistant will help lead the research, and results will be shared through field days, Extension meetings, conferences, videos, and online platforms.

D) Anticipated Impact. This work will give farmers and advisers field-tested answers about how integrated system that combines early planting, narrow rows and/or cereal rye crop crop perform compared with conventional programs. We expect the highly integrated system to reduce waterhemp density thus lower herbicide reliance, and maintain or improve soybean yield, while improving soil health and resilience to extreme weather which are both well documented benefits of cover crops. The project will produce practical recommendations, support adoption of integrated weed management practices, train the next generation of weed scientists, and ultimately contribute to more profitable and sustainable soybean cropping systems in the North Central region. 

Objective #1. Quantify season-long waterhemp control, end-of-season seed production, and soybean yield in contrasting soybean systems (conventional: tillage, no cereal rye; integrated: no-till, cereal rye), while evaluating the contributions of planting time, cereal rye cover crop, 6
and narrow row spacing to waterhemp suppression and reduced weed seed production in the integrated system.

Objective #2. Compare soybean growth and canopy development across the integrated systems.