Cover crop mixtures typically offer a wider array of benefits compared to single species. Cover crop blends can help mitigate weather-related risks during establishment, ensuring that at least one species survives.  One crop may serve as a companion or nurse crop to aid the establishment of the slower growing species and improve fall cover. If the goal is to utilize the cover crop for forage and feed for livestock, it is crucial to read and follow the plant-back restrictions on the label. This will help prevent issues with herbicide residues in animal by-products (meat, dairy products, etc.). 

Soybean Mix:  Cereal Rye (93%) and Radish (7%).  Cereal Rye is the anchor to most cover crop programs across the Midwest. This mix provides an outstanding combination of soil stabilization, nutrient scavenging, and soil tilth improvement ahead of soybeans. Rye establishes best when direct seeded, but some have had luck broadcasting the seed into standing corn.  It grows fairly rapidly in the fall, providing excellent biomass ahead of winter to keep soil in place. Timely spring termination is necessary before the rye sets seed to avoid excessive nitrogen immobilization. 

Corn Mix:  Oats (90%) and Radish (10%).  Excellent for soil stabilization, nutrient scavenging, and deep soil penetration. This mix establishes rapidly in the fall and normally winter kills, saving the grower the cost and time required to terminate the cover crop in the spring, which makes this mix well-suited for fields going to corn. This combination does not contribute as much residue as other cover crops, reducing the risk of nitrogen tie-up and crop biomass that could reduce timely planting of the corn crop.  

Quick Cover:  Annual ryegrass (65%) and Radish (35%).  This mix combines the extensive fibrous root system of ryegrass with radish tap roots allowing deep soil penetration and outstanding nutrient scavenging.  Broadcast the seed into a standing crop at least 60 days before a killing frost. This mix grows rapidly in the fall, but annual ryegrass requires intensive management in the spring and must be terminated before heading. 

 

Keep in mind that when planting a cover crop after soybeans or corn for erosion control or nutrient cycling, its establishment and growth may be hindered from either the preemergence residual or post emergence herbicide application (Tables 1 and 2). This is simply due to the herbicide not having enough time to degrade to levels deemed safe to the cover crop species succeeding corn or soybeans. Soybean herbicides that contain fomesafen (Reflex®, Flexstar® or Prefix®), pyroxasulfone (Zidua®, Anthem Maxx®), imazethapyr (Pursuit®), sulfentrazone (Authority® brands and Sonic®) and acetochlor (Warrant®) and corn herbicides that contain topramezone (Armezon® or Impact®), rimsulfuron (Resolve® Q), pyroxasulfone (Zidua®), mesotrione (Callisto® or Halex® GT), clopyralid (Stinger®, Tripleflex® II), isoxaflutole (Balance® Flexx, Corvus) and nicosulfuron (Accent® Q) can all have adverse effects on cover crop biomass accumulation. This may not be a serious problem if the cover crop is going to be used solely for erosion control and nutrient cycling. However, if the crop is to be used for livestock feed or forage, the plant back restrictions on the label must be obeyed.

Contact your local FS Crop Specialist for more information, and they can provide the expertise needed to help you successfully implement cover crops on your farm.