Riding Through the Winter on Grass in South Florida

October 2005
Dr. Ike Ezenwa - Southwest Florida Research & Education Center, Department of Agronomy

Annual ryegrass can help a rancher overcome nutritional stress experienced by grazing cattle on perennial tropical grass pastures that are dormant or unproductive during the winter and early spring in south Florida. Majority of ranches in Florida predominantly base their cow-calf operation on bahiagrass. The popularity of bahiagrass stems from the fact that the pasture fits into the extensive management system on most ranches. However, bahiagrass has some limitations, especially its relatively poor nutritive value during the summer and early fall. Even more important is the fact that bahiagrass nearly ceases growing by late September or early October when days become shorter. Thus, in the fall and winter, bahiagrass cannot provide adequate grazing. Most ranches with successful cow-calf operations include adequate arrangements for how to supply forage or feed to the animals during the winter. Besides, stockpiled forages, hays, wet and dry feeds, winter annual forages are important in accomplishing this task.

Annual ryegrass has shown the greatest potential in meeting forage needs in winter and early spring with forage containing about 30% crude protein and 80% digestibility. Research at the Range Cattle Research & Education Center, has shown that ryegrass can be the basis of a highly nutritious forage-based grazing system for managing calves during the winter under the early weaning system. Some factors that determine the overall success in using ryegrass as a winter forage during the winter in a cow-calf operation are the choice of a suitable variety, proper establishment practice, and fertilization. Others such as weather and cost of seed and fertilizer are not within the control of the rancher.

Varieties

Several ryegrass varieties are commercially available and new ones are being developed and released. Variety testing at Ona and Immokalee demonstrated little differences in forage dry matter yields among recommended varieties. The research showed that dry matter yield, seasonal forage distribution, and rust resistance are important attributes considered in the choice of a suitable variety. From these studies, varieties such as Gulf, Jackson, Big Daddy, Jumbo, Florida 80, Florida Rust Resistant, Rio, Surrey, and Tetrablend 444 have been recommended because of their consistently higher yields and rust resistance. These varieties can produce 3.0-3.5 ton dry matter/A during the winter season when planted in a clean seedbed. Selection among these recommended varieties should be guided by economics, mainly the cost of seed since performance among the varieties are similar.

Establishment Practice

The chances of successfully establishing ryegrass depend on soil moisture; adequate soil moisture means better establishment. Soil moisture may be more available in low-lying areas than on higher grounds. Thus, such low-lying areas may be more suitable for growing ryegrass. In general, residual soil moisture can be best utilized if the seed is sown (broadcast or drilled, but drilling puts the seed in closer contact with moisture) immediately after plowing, and the seedbed rolled to conserve the moisture for rapid grass establishment. Ryegrass establishes more rapidly and produces most forage when sown alone on cultivated, clean-tilled areas. Therefore, it is desirable that the selected area be dedicated (also called calf nursery in early weaning system) to ryegrass so that there will be no necessity of oversowing ryegrass on established sward. It is estimated that on a typical ranch, only 10 acres of land may be so dedicated to ryegrass-winter forage grazing of 50 early weaned calves at the optimal stocking rate of 4-5 calves/A. At the Range Cattle REC, the usual practice is to graze or mow in late summer to reduce volunteer vegetation in the calf nursery, apply Round-up (2 quart/A plus ammonium sulfate) in late September or early October, and burn in early November prior to sowing. Drilling seed into burned area (without plowing) conserves soil moisture, controls weed competition, and results in more rapid establishment than on prepared seedbed.

At Ona and Immokalee, the practice has been to sow the seed at 20 lb/A in late October/early November. When sown under suitable conditions (adequate moisture conditions), ryegrass can be grazed about 8 weeks after planting, and for 12 weeks, up to early April. As indicated earlier, greater success is achieved when ryegrass is sown alone on well-prepared seedbed than when sod-seeded.

Fertilization

Proper fertilization is important. Since ryegrass responds well to N fertilizer application, the practice can be used to maximize gains from the pasture. It is generally recommended to apply 30-30-60 lb N-P2O5-K2O/A at planting, and additional 50 lb/A at emergence or about 2 weeks after planting, and every 6 weeks. The following blend has worked well at Ona: 25-5-15-23 of N-P-K-S to provide 150 lb N/A applied at three occasions. The first dose is given at seeding or after emergence, and after 40-45 days. Additional benefit is obtained from application of micronutrients (as sulfates), but on dedicated lands, micronutrients (as sulfates) may be applied every three years based on soil analysis results. Target pH for ryegrass is 5.5-6.0, but where pH change is desired, lime or dolomite should be plowed into the soil about 3-4 months prior to planting.

Annual ryegrass can improve performance of grazing cattle during the winter in south Florida. However, successful use of ryegrass will depend on adequate planning, and proper pasture and grazing management. Greater success is achieved with suitable varieties planted on clean-tilled soil, with adequate soil moisture. Irrigation, where available and economical, can improve the chances of success with ryegrass. Even though ryegrass produces good quality forage, supplements based on natural proteins such as cottonseed meal and blood meal can economically improve animal performance.

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