Diversified rotations improved yield performance and profitability in a 16‐year, no‐input experiment

Abstract

Diversified crop rotations offer multiple agroecosystem benefits like closing yield gaps, reducing environmental impact, improving resiliency, and enhancing farm profitability. We used data from a 16‐year crop rotation experiment in SW Michigan that was conducted with no external agrochemical inputs to isolate and evaluate the “crop rotation effect” on grain yields, the relative yield gap compared to county‐level means, and profitability. Treatments were maize ( Zea mays L.), soybean ( Glycine max L. merr.), and winter wheat ( Triticum aestivum L.) systematically diversified in combination with one another and non‐harvested winter cover crops (red clover [ Trifolium pratense L.] or crimson clover [ T. incarnatum L.] and cereal rye [ Secale cereale L.]). Across all three cash crops, adding any crop in rotation reduced relative yield gaps compared to monocrops by ∼77%, 20%, and 58% for maize, soybean, and winter wheat, respectively. Diversified rotations, particularly those including leguminous cover crops, increased maize and winter wheat grain yields by up to 95% and 64% relative to 2‐ and 3‐year rotations without legume cover crops and improved economic returns (>300%). Diversified rotations provided measurable productivity and economic gains in the absence of confounding management practices that have historically obscured the rotation effect.