Forage regrowth after a hay harvest tends to be rather uniform considering the cut height was the same across the stand. With that said, uneven regrowth in a hayfield may raise questions surrounding soil fertility, plant health, and harvest management.
In the University of Arkansas’s Animal Science E-News newsletter, Kenny Simon notes there has been an uptick in reports of uneven bermudagrass hayfields in his state. The extension forage specialist described such stands as having patches of tall bermudagrass interspersed with short, early maturing plants that lower forage yield.
Simon concludes the shorter plants are most likely varieties of common bermudagrass that have encroached hybrid bermudagrass hayfields. Although low potassium levels, plant disease, and winter injury could have weakened stands and made them susceptible to this encroachment, the issue could also be caused by mower height.
An unfair advantage
Simon notes hybrid bermudagrass tends to be tall and grow upright with an open sod while many varieties of common bermudagrass are low growing with a dense sod, especially near the soil surface. If hay producers lower their mower height in attempt to harvest the shorter forage, they ultimately give common bermudagrass a competitive edge over hybrid bermudagrass.
“The remaining stubble of the hybrid bermudagrass plants tend to look like brown, dead stubs, whereas the remaining stubble of the common bermudagrass plants tend to look green like a lawn due to the amount of leaf left below the cutterbar,” Simon asserts. “Guess which plant type captures sunlight and begins regrowth sooner after harvest?”
In a study conducted in Georgia, researchers found greater rates of common bermudagrass in Coastal bermudagrass stands that were cut too short or overgrazed. Results from the study also show the overall density of stands that were cut too short declined by 3% each year.
To prevent the encroachment of common bermudagrass in hybrid bermudagrass stands, Simon recommends raising the mower height 1 inch during the next harvest. Above all, aim to keep plant stubble at least 3 inches to ensure hybrid bermudagrass can outcompete common bermudagrass in a hayfield.