As I write this, the weather forecast calls for two weeks of temperatures in the 90s and lots of sunshine. Good weather for haymaking but not so much for cool season pasture, especially if you are short of soil moisture like we are in Central Kentucky. Historically, pasture condition scores in Kentucky are worst in October (when these kinds of measures were kept). Here are some thoughts that are rattling around in my head about fall pasture management.
First, keeping at least four inches of growth on pastures is always the goal for our cool season grasses. Orchardgrass is especially sensitive to overgrazing. Leaving a good residual shades the crown of the plant and protects the stem bases where carbohydrates are stored. Hopefully these carbohydrates will be available to fuel growth later this fall. When stands are defoliated to one inch, temperatures are elevated four inches deep into the soil. Keeping four inches of residual height benefits cool season grasses significantly.
Maintaining four inches in a toxic fescue stand benefits the grazing animal as well. The greatest concentration of ergovaline in toxic tall fescue is present in the base of the plant. The stem bases are even more toxic than seed.
The weed control effects of leaving a good grass residual can’t be over-emphasized, in my opinion. Short grass stands allow weed germination of winter and summer weeds. Most of the buttercup we see in the spring gets its start as a fall-germinating seedling.
Skeptical? Look around now in your pastures and take a weed inventory. Many of the pastures I am in have an invasion of ragweed and some pigweed. We are also seeing signature weed of overgrazed pastures – foxtail. I can’t promise you that leaving four inches of residual will eliminate these and other annual weeds from your pasture, but it darn sure is going to help.
If you have hung with me so far, no doubt you are thinking, “Okay Mr. PhD, the cows have to be somewhere!” And you would be right. Here is a short list of possible solutions.
Feed hay now. Put the cows in one pasture and feed hay now, especially for your spring calvers that are almost ready to wean. This practice has several advantages. First you limit the overgrazing to just one pasture. Second you can accumulate a lot of nutrients in that pasture from the manure and urine. Third, you can feed your low quality hay now when the cows have their lowest nutritional need.
Use summer forages. Long term, consider some type of recurring summer pasture. You could use summer annuals like sorghum-sudangrass, crabgrass or even corn. Sorghum-sudans and corn require killing the existing vegetation. Crabgrass on the other hand can be broadcast seeded into cool season grass pastures that have been damaged by hoof traffic in spring or that have been lightly tilled to expose soil. Crabgrass is often mixed with red clover to improve pasture quality and yield. Running a cultipacking roller over these overseeded fields will improve establishment. The use of one of the improved varieties of crabgrass like Red River, MoJo or Quick N Big is recommended.
Native warm season perennial grasses are another good summer option . Big bluestem, indiangrass and eastern gamagrass are used with success in Kentucky for high quality, mid- and late summer grazing. These grasses have the advantage of being perennials, highly palatable and very efficient users of fertilizer. Their downsides include slow establishment and high seed cost. Cost-share programs available through agencies such as NRCS or Kentucky Fish and Wildlife can greatly reduce establishment costs.
Finally, bermudagrass may be an option. Both the seeded-types and hybrid bermudagrasses can be grown in Kentucky. The seeded varieties are more winter hardy but less palatable. The hybrids are better adapted to the lower tier of counties in Kentucky due to their limited winterhardiness. Both types will need high levels of soil fertility, especially nitrogen for productivity and stand longevity.
Pasture management is always a series of compromises, and a hot dry fall can have us seeking the lesser of evils. Overgrazing in the fall on at least some of the farm may well be impossible. Limiting the extent of this close defoliation can help you have greater regrowth later this fall, and more vigorous, less weedy pastures next spring and summer.