Although Florida has a mild winter climate compared to most of the United States, warm-season perennial forages provide limited grazing during the late fall and winter months. As a result, little forage is available from perennial grasses from November until April, except for cool-season (winter) annual forages. However, successful tillage systems and overseeding of perennial pastures can improve performance of winter annual forages. Planting after harvest of cotton, peanut, and other row crops is an option for quick establishment of winter cover crops on fertile row crop land that may produce more forage than overseeded pasture land that is not normally as fertile.
In north Florida availability of winter forages ranges from December until May (Table 1). Understanding when various winter forages are most productive is important to designing a forage program that best suits livestock and crop enterprises. Blends of certain forages will allow for extended winter grazing and stability of a forage system, which is desirable until adequate summer forage is available.
Winter Forage Production When Planted on a Prepared Seed Bed
If winter annual forages are planted on prepared seedbeds, the forages can be planted earlier than if overseeded into perennial grasses. Small grains are desirable for early planting. Seeding rates for small grains and planting dates are shown in Table 2. Early planting on prepared seedbeds almost always provides earlier grazing than overseeding perennial grass pastures.
When deciding what varieties of winter forages to grow, study variety trials from state tests. These tests demonstrate differences in yields and time of production of these varieties. Early maturing varieties of wheat, oats, and rye produce more forage early in the season when livestock forage needs are critical. Oats offer an advantage because they may be planted earliest of the small grains. Rye has the best cold tolerance.
Determining which species of winter annual forages to plant will depend on soil type, as well as the moisture-holding capacity of the soil. Rye is best for sandy soils. The other small grains will do well on heavier soils. Ryegrass and crimson clover grow best on moderately well-drained soils, but not on deep sands. If irrigation is available, all small grains, clovers, and ryegrass can do well.
Production of late-season winter forage is also possible. Some forages, including ryegrass, will continue to grow into May and June with adequate moisture. Red and white clover (cultivars of red clover include 'Southern Belle' and 'Cherokee') will produce into July and August in north Florida if moisture is not limited.
Overseeding Winter Forages on Bahiagrass or Bermudagrass Pastures
Bahiagrass is the predominant perennial grass in Florida pastures. Many bahiagrass pastures are overseeded with winter annual forages. Bahiagrass is more competitive than bermudagrass, and results of a three-year study in Florida comparing overseeding pastures showed that wheat produced less forage when overseeded into bahiagrass than when overseeded into bermudagrass. The study also showed that overseeding of wheat with a no-till drill into bahiagrass produced forage for grazing several weeks later than wheat overseeded in bermudagrass.
In general, more tillage will be necessary to reduce competition from bahiagrass with the winter annual forage than when overseeding in bermudagrass. Keep in mind that tillage has certain disadvantages. Tillage may delay and reduce tonnage of bermudagrass and bahiagrass the next year, especially if ryegrass is not heavily used in May, when the perennial grasses begin to grow for the year.
If bahiagrass or bermudagrass is to be overseeded successfully with winter annual forages, the following steps should be taken to ensure success:
Overseed bahiagrass a few weeks later than for bermudagrass, probably in November or at least after cool weather has slowed the growth of bahiagrass. Be sure that adequate moisture is available for germination of the winter annual.
Graze bahiagrass or bermudagrass close prior to planting winter annuals. If the field has to be planted early, use a growth-regulation chemical, such as paraquat, on bahiagrass to knock top growth and reduce competition with the winter annual.
Provide tillage on bahiagrass pastures or an aggressive no-till drill when overseeding in bahia or bermudagrass. For bahiagrass and bermudagrass pastures, make sure the no-till drill is cutting through the organic layer or surface root system to allow for sufficient contact between the soil and seed. Bahiagrass should be tilled heavily enough that it does not regrow immediately.
If planting on a clean-tilled seedbed following bahiagrass or bermudagrass, allow several weeks for plants to decay before planting, as the decaying process will tie up nitrogen needed for growth of the winter annual.
Use early maturing varieties of small grains to minimize the influence of the winter grazing on production of summer grass.
Generally, small grains, winter legumes (such as clover), and ryegrass planted in clean-tilled seedbeds will produce forage two to three weeks earlier than forages planted into bermudagrass. Winter forage planted into bermudagrass will produce forage one to three weeks earlier than when planted into bahiagrass. Total yield of winter forage is highest in the same order: clean-till > bermudagrass > bahiagrass.
Since winter grazing is normally needed by December, plant these forages about eight weeks earlier. An example of ideal timing would be to plant wheat, oats, rye, or triticale on a prepared seedbed in October. Data show that overseeded bermudagrass will produce as much total forage over the season as a prepared seedbed, but in most years the forage produced in that way will not be ready to graze until mid-January.
Overseeding Winter Legumes on Bahiagrass and Bermudagrass Pastures
Data in Table 3 show that overseeding legumes can contribute to the overall production of bahiagrass. Crimson or arrowleaf clover can contribute in the range of 50–200 lbs/A of N for bahiagrass. Depending on the current cost of N, legumes may produce $30–$100 N/A.
Winter legumes can provide grazing in March, April, and May, before bahiagrass starts its growth. However, the cost of establishing legumes can be as much as $30–$50/A. New releases of red clover may provide longer season grazing than other legumes. The longer season clovers can also add extra N since most producers seldom apply more than 100 lbs/A of N to bahiagrass pastures. These clovers add 2–3 tons more dry matter to the total forage (bahiagrass-clover) produced during the year.
Dry fall seasons often discourage producers from overseeding pastures since stand failures occur due to a lack of seed bed moisture. Additionally, cold temperatures may delay the growth of the winter forages or cause some cold damage to the young, tender plants. Adequate rainfall is key to the success of any winter annual forage program.
Tillage and overseeding practices to consider for the most economic production of cool-season forage annuals include the following:
Use open land or areas that have been cropped for early planting and early grazing. Use a chisel plow to break the compaction layer in the soil for better root penetration for the winter forage.
Select proper forage species for the time that grazing is needed.
Soil test and apply proper nutrients prior to maximum growth stage for optimizing production. If legumes are to be planted with small grains, check soil pH and apply lime several months ahead of planting if needed.
Plant the crop in the early part of the seeding date range if planting on a clean-tilled seedbed. If overseeding bermudagrass, delay planting until the last half of the seeding date range. When overseeding bahiagrass, delay the planting date another two to three weeks.
Wait for proper moisture when overseeding into sod. No-till drills need adequate moisture to penetrate through the sod to ensure good soil-seed contact.
Use proper inoculant if planting legumes.
Forage species mixture will result in a more evenly distributed forage production season, compared to planting a single species.
Many producers use no-till drills with good results on bahiagrass sod. No-till drills are sometimes available for rent through the local soil conservation district or seed/fertilizer dealer. Drills differ in the amount of tillage they do. Many no-till drills have straight cutting coulters in front for cutting through the sod. Other no-till drills have more aggressive coulters that act more like off-set harrows and cut and remove more sod out of the seed furrow. There are many no-till drills on the market that have advantages in different planting situations. All no-till drills can do a good job if moisture is adequate and the sod is cut or grazed short before planting.
Do not overgraze or graze the winter forage too early, as stand loss will result. Most small grains should not be grazed closer than 3 inches.
Consult with your local UF/IFAS Extension office for updates on best winter forage selection and best management practices.
Forage production periods for several cool-season forages recommended for north Florida.
Seeding rates and dates for small grains and ryegrass for winter forage.
Total seasonal production of bahiagrass alone and with three overseeded legumes.