The time following wheat harvest presents an opportunity to incorporate cover crops. Most of our district has received enough moisture to grow a cover crop with substantial biomass, which could also serve as forage for livestock.
The following is a summary of “Cover Crops Grown Post-Wheat for Forage Under Dryland Conditions in the High Plains”. The entire fact sheet can be viewed and downloaded at https://bookstore.ksre.ksu.edu/pubs/MF3523.pdf.
Determining what to plant can be difficult given the varied species available for cover crops. For Kansas producers, local Land Grant Universities, and the Midwest Cover Crops Council, have developed a decision tool to help select species based on specified goals.
Goals for the timing and length of grazing are considerations in species selection. For early to late summer planting, crops can be grazed late summer through early fall. Warm-season species such as millets, sorghum-sudangrass, sudangrass, forage sorghum, sunflowers, cowpeas, lablab, or sunn hemp should be considered potential species to grow.
Complex mixtures of 6 or more species, often called “cocktails,” are commonly promoted. Research studies at Kansas State University and other universities have not found a benefit to cocktails compared to single species or simple mixtures of 2 to 4 species.
When managing grazing of cover crops, numerous options can be considered. The ultimate strategy chosen will be influenced by your overarching goal(s) for the cover crop. Cover crops are generally grown for more reasons than just achieving high levels of harvest efficiency as you would if this were a dedicated forage crop. You want to leave enough residue to maintain most of the benefits associated with planting cover crops.
The next decision to make is when to start grazing your cover crop. The timing of grazing relative to frost is an important consideration for post-wheat-planted cover crops. The biggest concern is with plants in the sorghum family, as frost damage to cell walls can release prussic acid. A forage planted immediately after wheat harvest can provide 30 or more days of grazing before frost. In other cases, delaying grazing until after a hard frost may be easier, particularly when it may be time-consuming to move animals on and off the field and difficult to predict frost timing. Grazing should be suspended for 7 to 10 days after a frost to avoid prussic acid poisoning. For plants with prussic acid potential, delay grazing until plants reach 18 to 24 inches of growth, as prussic acid is highest in small plants or regrowth.
Several key pieces of information are needed to estimate a stocking rate. Calculations can be made to estimate days of grazing for a given number of animals or the number of animals for a set grazing period. A Carrying Capacity Calculator located at https://www.drylandag.org/resources.html is also available to help with these calculations.
Taking advantage of the recent rains and full soil profile is an economical way to add grazing days for your livestock as well as helping your soil with the benefits of cover crops. If you would like to get the entire publication, you can contact our offices and we can get it to you.
Alicia Boor is an Agriculture and Natural Resources agent in the Cottonwood District (which includes Barton and Ellis counties) for K-State Extension. You can contact her by e-mail at aboor@ksu.edu or calling 620-793-1910.
K-State Extension is an equal opportunity employer and provider. Kansas State University, County Extension Councils, Extension Districts, and U.S. Department of Agriculture Cooperating.