OATS AS A COVER CROP FOUNDATION
It is that time of year again to plan for your fall cover crop needs, and we encourage you to reach out to us to help make that plan. Rye has a long-standing history as the foundation for growers looking to use a cereal grain ahead of their next cash crop. Given most of the rye we use in the Southeast comes from the high plains, seed supply can be extremely volatile from year to year (think heat and drought this year across that region), as well as costly (think freight). We believe there is a better option = high quality, locally-produced oats. Below we discuss a few factors like biomass, nematode and hessian fly resistance, ease of termination and flexible crop use that make quality oats a more functional, sustainable foundation for most of our Southeastern cover crop mixtures.
Ample biomass is crucial in cover crops and high-quality oats perform very well when compared directly to rye. Rye tends to get stemmy as the plant reaches full canopy height. Oat biomass is a very different cover, as it is well-tillered and leafy, providing a fuller ground cover to smother weeds and provide superior soil protection. Below is data from University of Georgia OVT testing for the 2022-2023 season. Seasonal total tonnage produced by oats, triticale, and rye throughout the growing season, across four testing locations, is presented in Table 1. The data shows Horizon 306, Horizon 578, and Horizon 214 oats outperformed the top two competitors of rye and triticale in total seasonal yield per acre across all locations. Comparative harvest date yield performance at Tifton, GA at different harvest dates is shown in Table 2. Oat yields remain steady in tonnage yield throughout the season, then ramp up in the last month of growth. Rye and triticale tend to produce slightly more tonnage in the middle of the season, whereas oats really stretch their legs a little later.
Table 1. University of Georgia State Variety Testing forage data from the 2022-2023 multi-location trials.
Table 2. University of Georgia State Variety Testing forage data from the 2022-2023 Tifton, GA trials
Nematodes cause significant damage to our spring crops, robbing growers of healthy plants and good yields. Small grains are generally considered non-hosts or poor hosts to many of our common plant parasitic nematode pests, and this makes them a first choice as winter cover. There are advantages to using oats specifically as the small grain of choice. Natural nematode resistance has been reported in oat to some root-knot (Meloidogyne species) nematodes and to the cereal cyst nematode (Heterodera avenae). An advantage of using a nematode resistant or non-host oat as a stand-alone cover crop or in a blend, is the potential reduction of spring nematode populations that might impact our spring crop plantings.
Hessian fly (Mayetiola destructor) had a significant impact on wheat grain yields in many areas of the Southeast this past season. Wheat planted as an early cover crop may increase the pressure from Hessian fly infestation across a wide area, which can harm young stands causing stunted growth or premature lodging. While rye and triticale tend to be less susceptible to Hessian fly, Alabama A&M and Auburn University Extension report that Hessian fly does not affect oats. This is a critical advantage for oats, especially in wheat-growing regions. Alternating to a cover crop such as oats will help break up the life cycle of Hessian fly, and eventually reduce Hessian fly pressure in those areas.
When it is time to plant the cash crop, we must consider cover crop termination. Oats, just like rye, can be roller crimped, leaving a thick mat of vegetation that enables good weed suppression. Since oats are better tillered and much leafier than rye, the resulting cover should be uniformly dense and suppressive to wees. Important consideration should be taken that the oats are well into the late milk or dough stage of grain fill, as crimping too early while actively growing (vegetative stage) will possibly allow the oats to stand back up. If herbicide is used for termination, oats can be easily killed via herbicides, such as glyphosate. Planting date and the type of tillage equipment should be considered when deciding when to terminate. A good rule of thumb would be two to three weeks ahead of stripping/planting.
Flexible Crop Use
Another benefit to using oats as a cover crop would be the option and flexibility for growers to graze and/or cut for silage or bailage. What starts as a cover crop, could in fact be fertilized and grown for forage, giving oats a strong added value. Additionally, oat hay is highly nutritious, so harvesting in the boot or later growth stage offers a quality hay product and allowing an oat cover to fully mature to seed, will produce excellent feed. Our Horizon Oats are top performers across both forage and grain trials.
Blend Component Advantage
Multi-specie cover crop blends are on the rise in popularity, and for good reason. Specie diversity in cover crops is a foundation behind building the organic matter that we are chasing. Many of the alternate specie crops such as brassicas and legumes are small seeded and have high potential to settle in a blend of dense cereals, such as wheat, triticale, and rye. By adding oats to cover crop blends, their lighter test weight, larger seed size, and slightly rougher chaff, prevents settling of small seed and keeps these smaller cover crop components in suspension once the blend is in a bag or container.
In summary, we believe high quality, locally produced oats can and should be the foundation for much of our Southeastern cover crop needs as they are more functional and sustainable than most all the other options.