Intercropping food-grade oats and clover to improve water quality and reduce nitrogen fertilizer inputs

Commodities

Practices

Upper Midwest farmers are actively looking for new market opportunities to broaden their crop portfolios and lessen their reliance on a small number of globally volatile commodity markets. Recent geopolitical events have stressed grain export markets for Midwest farmers and have increased the cost of synthetic fertilizers. Crops with domestic markets and reduced fertilizer requirements have potential to increase farmer profitability, homegrown healthy food ingredients, and rural vitality. Food-grade oats show promise to achieve these goals in the Upper Midwest. In the last decade, farmers and processors have been building a food-grade oat industry across SE Minnesota, NE Iowa, and SW Wisconsin. Their efforts include the construction of a 3 million bushel per year oat processing plant scheduled to open in 2026, Green Acres Milling. Motivation for this work is not only driven by economic opportunities, but also the potential for oats to reduce nitrate contamination to local drinking water. This new generation of oat farmers is planting red clover with their oats to reduce synthetic nitrogen fertilizers often used for achieving profitable yields of oat and subsequent corn crops. This practice has grown among a regional group of farmers referred to as the Oat Mafia, and this project is aimed to quantify the economic and ecological benefits of intercropping oats and red clover. Calls for this research have been made for years, and this proposal is our response to support sustainable oat production in the Upper Midwest. Based on grower experiences and input, we will conduct a multi-site field trial at research stations in conjunction with on-farm trials to 1) quantify the nitrogen credit of red clover to oats when grown together in an intercrop, 2) future nitrogen credits of clover to subsequent corn crops the following year, and 3) the economic benefits of these outcomes. These studies will also measure the fate of nitrogen in soil, soil water, and crop tissues to estimate nitrate leaching reductions to groundwater. The project will actively involve oat farmers and three local non-profits across three states (MN, IA, and WI), each with long-standing partnerships with farmers, to ensure that project results meet various stakeholder needs. A comprehensive, farmer-driven outreach program will disseminate findings to strategic audiences via multiple modes of information transfer including on-farm field days, winter workshops, written articles, podcasts, and YouTube videos. We will use the project collaborators' well-known, trusted, and accessible platforms for providing practical information to growers.

Objectives:

• Determine effects of clover intercropping on oat yield and test weight.
• Estimate nitrate leaching beneath oats fertilized with various rates of nitrogen fertilizer with and without clover intercrop.
• Quantify the nitrogen credit of clover to oats and subsequent corn.

Learning outcomes:

• Knowledge on how oat-clover intercrops can improve oat yield and test weight.
• Knowledge for farmers to reduce nitrogen fertilizers applied to oats and subsequent corn.
• Knowledge on how oats reduce nitrate leaching to drinking water.

Action outcomes:

• Increased farmer profits when growing oats.
• Increased acres of oats and clover intercropped oats.
• Reduced nitrate leaching to drinking water.