Demonstrating relay intercropping as a sustainable soybean intensification option

Commodities

Practices

Title: Demonstrating relay intercropping as a sustainable soybean intensification option

This project aims to improve farmers' understanding of the benefits and implementation logistics of relay intercropping - specifically, how to plan/manage this system, how crops compete with each other, and how system interactions influence yield and environmental aspects (ecology). We aim to generate practical information that can be translated into recommendations for farmers. Farmers will also implement/test relay intercropping on their own farms through partnerships with Extension agents, contributing to research in the long term. Results will be published through papers, extension updates and publications, presentations at regional and national conferences, field days and social media, aiming to reach farmers, extensionists, and researchers.

Sustainable intensification is a common theme in modern agronomic practices, with the goal of increasing production and minimizing environmental impacts. In the North Central region, double cropping is a common strategy to extend the growing season, although it typically results in lower short-season yields and remains a monoculture system by design. Polyculture, while tricky to implement, may offer some creative alternatives to the status quo. Relay intercropping involves planting a warm season crop into a standing cool season crop before harvest, allowing both crops to share part of the growing season. This system could reduce yield limitations of similar double-cropping systems, while improving soil cover and weed management challenges of monoculture systems. As soybeans and wheat are key commodities in the North Central region, these are good candidates for implementing such a relay system. However, there are many questions regarding relay intercropping logistics and implementation - planting soybean into standing wheat, harvesting wheat while soybeans are growing, row spacing, herbicide programs, and overall performance of the crops in this system, to name a few.

This project is currently in its first year. In addition to a nation-wide soybean intensification and intercropping survey (capturing farmer interest, needs, and implementation barriers) that will be disseminated in July, we have plot trials at three locations in Kansas, evaluating four cropping systems with two planting dates: relay-intercropped wheat-soybean, double-cropped wheat-soybean, full-season soybeans and full-season wheat. To understand system ecology, we are collecting crop biomass and recording phenological stages. Soil moisture and light interception are being collected to understand crop's competition and use of resources. System yields will be determined with an accompanying economic analysis. Coming years will involve on-farm trial establishment with collaborating farmers in the region.

Ultimately, this project seeks to connect farmers with university-led research trials and Extension efforts and spark curiosity and optimism about regenerative and sustainable practice options for their farms. The use of small research plots allows us to understand how the relay intercropping system performs before encouraging on-farm trials. Using small research plots, we expect to generate data to provide recommendations to farmers for implementing relay intercropping.

Upon completion of this project, participating farmers will improve their understanding and awareness of the economic, agronomic, and overall sustainability benefits of incorporating this practice on their farms. As a key element of the larger project, we are evaluating farmers' curiosities, perception of risk, and willingness to implement this system through a nation-wide survey prepared for dissemination in July 2025. Survey data will inform relevant, on-farm trials during the life of this project. This outcome will be gauged by the number of publications and events accompanied by the number of participating farmers.

Action outcomes from this project include farmers implementing relay intercropping on their own farms and engaging in future relay intercropping research trials (beyond the life of this grant). These outcomes will be gauged by the number of farmers implementing test plots on their farms, the number of farmers reaching out for more information or assistance in implementing this system on their farms, and feedback from Extension agents on farmer behaviors (relay intercropping system implementation, interest, etc.) in the agents' districts.