Cereal Rye as a Cover Crop
By now, producers in the midsouthern U.S. are familiar with the pros and cons of incorporating a cover crop (CC) into their soybean and corn production systems, or into a rotation system of the two. Also, after many years of cover crops’ research in all sections of the U.S., it is obvious that one particular species is superior when the goals are to assist in weed control, scavenge nitrogen (N) that may be remaining in the soil after harvest of a grain crop, and/or produce a large amount of biomass that can be left on the soil to impede summer weed emergence and increase soil organic matter (OM).
So the remainder of this article will deal with that species, which is cereal rye. The details of its use as a cover crop are contained in a White Paper that is posted on this website. Major advantages from using it as a cover crop are: 1) it is winter hardy; 2) it’s seed are relatively inexpensive; 3) it is an excellent scavenger of unused/residual N; 4) it produces a relatively high amount of biomass; 5) its rapid resumption of spring growth ensures that it will out-compete many winter annual/early emerging spring weeds; 6) it works well with a companion legume CC species such as hairy vetch; and 7) the environmental benefits of a killed cereal rye CC do not impact corn or soybean yields.
It is generally accepted that this CC species, when following a grain crop such as corn or grain sorghum, will likely result in an over-abundance of residue that could impede soybean planting. Thus, residue management will become significantly more important if cereal rye is used as a CC following a grain crop (particularly corn that has been irrigated) before soybean planting. Ways of managing this residue are detailed in a White Paper that is posted on this website. One of the more promising approaches when cereal rye follows corn is to remove a portion of the corn residue to be sold as an ethanol feedstock. This will offset a portion of the expense associated with planting and managing the rye cover crop.
The following points should be considered when using cereal rye as a cover crop.
• It must be planted early enough in the fall to ensure adequate establishment and fall growth prior to onset of cold temperatures.
• It must be terminated sufficiently close to planting of the summer crop to ensure that it has produced enough biomass to accomplish the intended purpose from its use, and yet not interfere with timely planting of the following summer crop. For this reason, it should be planted following corn vs. preceding corn in the Midsouth since corn is planted too early to allow for sufficient biomass accumulation to occur before termination of the cereal rye CC.
• It must be terminated before seed formation–i.e., no later than flowering.
A final note. Results from numerous research projects indicate that no cover crop, not even cereal rye, will completely control winter or summer annual weeds that will always be present at a site that will be used for a summer crop. Rather, a cereal rye CC should be used as a component of an integrated weed management system to supplement weed control by efficacious herbicides. When used in this manner, it will reduce both winter and summer annual weed populations while also providing the environmental benefits attributed to its use.
Hopefully, Midsouth soybean producers have already incorporated or are planning to incorporate cover crops into some or all of their cropping systems in order to enhance crop production and improve soil health. To this end, cereal rye is certainly worthy of consideration since it can provide multiple benefits from its use in the long-term.
Composed by Larry G. Heatherly, Aug. 2022, lheath91746@gmail.com