Perennial cover crops

aerial view of crop research plots, with a patch work of colors
Figure 1: Aerial view of cover crop research plots.

University of Minnesota research suggests there’s potential to grow corn and soybeans with perennial cover crops. While there’s a yield deficit, perennial cover crops may be an option in highly challenging watersheds and field areas subject to heavy erosion.

However, more research is needed to maximize cash crop yields by minimizing early-season competition from the perennial covers.

Why study perennial cover crops

From soil stabilization to nutrient capture, the benefits of cover crops are abundant.

Yet, the most common cover crops, such as rye, radish mixtures or hairy vetch, don’t provide options for yearlong vegetation. Managing these annual cover crops tends to leave the soil exposed at periods of heavy rainfall, particularly in the early spring.

Research on perennial cover crops

To hopefully enable continuous vegetation in corn and soybean rotations, University of Minnesota researchers are trying to discover perennial cover crop species and management options.

The research aims to grow corn and soybeans in a perennial cover crop to maximize the yield of the cash crop, while maintaining continuous living. This would fully harness the environmental benefits of perennials in annual crop rotations.

To minimize early-season competition, researchers combined localized desiccation with broad suppression of the perennial cover crops. Researchers conducted the study at three locations: Rosemount, Waseca and Lamberton.

Evaluating species and management techniques

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Yield results

Figures 4 and 5 show corn and soybean yield results from the Lamberton location.

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bar graph showing corn yield by type of cover crop and type of cover crop termination method.
Figure 4: Corn yields with perennial cover crops in Lamberton. Red bars show band-killed prepared seedbeds; blue bars show rotary-zone-stripped, seed-prepared seedbeds.
bar graph showing soybean yield by type of cover crop and type of cover crop termination method.
Figure 5: Soybean yields with perennial cover crops in Lamberton. Red bars show band-killed, prepared seedbeds; blue bars show rotary-zone-stripped, seed-prepared seedbeds.

Rebekah Carlson, graduate student, College of Food, Agriculture and Natural Resource Sciences; M. Scott Wells, Extension agronomist and John Baker, soil scientist, USDA Agricultural Research Service

Reviewed in 2018

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