Annual ryegrass, Lolium multiflorum, has been overseeded into bermudagrass pastures for many years. It can provide excellent early spring forage production for either grazing or hay. If fall rains arrive, the overgrazed and moisture-stressed conditions that exist in bermudagrass pastures following drought provide the ideal environment for ryegrass establishment. This scenario happened following the 2011 drought, and the forage ryegrass produced in 2012 was a lifesaver for livestock producers. Unfortunately, it also hurt bermudagrass production by competing for moisture, nutrients and sunlight during the prime portion of the bermudagrass growing season. The combination of this competition, along with the severe winter of 2010 and hot, dry summers of 2011 and 2012, resulted in low vigor or severe stand reduction in many bermudagrass pastures. This article provides management guidelines to benefit from ryegrass while encouraging bermudagrass recovery. While the focus is on ryegrass in bermudagrass, the same principles apply to other cool-season annuals in other warm-season perennial grasses.
First, collect quality soil samples and have them analyzed at a reputable agricultural laboratory. Inform the lab that the samples are for ryegrass overseeded into bermudagrass. These samples are necessary to determine phosphorus, potassium and lime requirements for both ryegrass and bermudagrass. Ryegrass begins to germinate in the fall, so that is when to apply the recommended lime, phosphorus and potassium for the ryegrass component. If ryegrass establishment is rapid and environmental conditions are favorable, up to 60 pounds of actual nitrogen per acre may be justified in the fall. If it will be grazed, turn cattle out when the ryegrass is well rooted and at least 6 inches tall. Ryegrass growth is slow when temperatures are less than 45 degrees F, so it usually does not reach this stage until early spring. When temperatures are consistently in the 60s and 70s, and with adequate moisture, ryegrass will go through a period of rapid growth, referred to as the spring flush.
Prior to the spring flush, apply up to 60 pounds actual nitrogen per acre, depending on forage needs. In southern Oklahoma and northern Texas, the spring flush usually begins in March and growth continues until late May or June. Since bermudagrass produces up to 70 percent of its total yield between late April and June, it is vital to remove the ryegrass pressure before May 1. During the spring flush, growth is often so rapid that stocking rates of 2,000 pounds per acre or more may be necessary to provide enough grazing pressure to remove most of the ryegrass.
If haying will be used, set the cutter bar as low as it can safely run in order to remove as much ryegrass as possible. One major concern with the hay option is the difficulty drying the hay before baling. A possible remedy for this issue is to put up the ryegrass as baleage instead of dry hay.
Now the focus changes to bermudagrass recovery. The first step is to apply phosphorus and potassium as recommended by the soil test. These nutrients are important for rebuilding damaged root systems and for moisture and nitrogen use efficiency. Nitrogen rates depend partly on how badly the bermudagrass stand was damaged. For severely damaged stands, apply up to 50 pounds actual nitrogen per acre. If the stand is still relatively solid, apply up to 100 pounds actual nitrogen per acre. Second, control weeds, as needed, early in the season. Remember that bermudagrass cannot grow back into a spot already occupied by a weed. Finally, use a conservative harvest approach. Delay grazing or haying activities until the bermudagrass has an opportunity to recover and is growing back into the bare spots. Also, maintain a higher than normal stubble height. Do this by rotating cattle to another pasture earlier or cutting the hay higher than normal. Leaving extra leaf will allow the bermudagrass to devote more energy to drought recovery.
By following these guidelines, one can take advantage of ryegrass’s benefits and still allow bermudagrass to recover.
Source: James Locke