Charles Stichler, Extension Agronomist, Uvalde
David Bade, Extension Agronomist, College Station
In April of 1943, with the introduction of Coastal bermudagrass (an F1 hybrid between selections from Georgia and South Africa), forage production with perennial grasses changed dramatically and permanently. Hybrid bermudagrass is sterile and will not produce viable seed, so it must be vegetatively propagated and is usually planted by using "sprigs." Sprigs are made up of either root pieces or rooted stolons or runners.
Immediately after its introduction, extensive research began in many states to evaluate the forage potential of this hybrid grass under various management schemes. Experiments with nitrogen rates as high as 1,800 pounds of actual nitrogen per acre and other nutrients were conducted under dryland and irrigated conditions to determine just how much forage this new "miracle" grass could produce. Countless feeding trials were also conducted to determine the digestibility and nutritive value under various management practices. Since then, Coastal bermudagrass has become the standard by which other grasses are compared.
These trials have shown that Coastal bermudagrass is more drought and grazing (defoliation) tolerant than many grasses. These tolerance levels are due to its spreading growth by stolons and rhizomes and its ability to reestablish itself if mismanaged or partially killed out. It responds well to adequate fertility and rainfall or irrigation and can grow under a variety of soils and climatic conditions in the South. However, Coastal bermudagrass is susceptible to freeze injury and will be killed out in areas where the soil freezes. It is truly a "miracle grass" in many ways.
Since the introduction of Coastal bermudagrass, there have been many introductions of similar hybrid grasses: Coastcross-1, African Star, Alecia, Callie, Tifton 44, Tifton 78, Brazos, and, recently, Grazer, Tifton 85, World Feeder, Russell, and Jiggs. These newer selections are rapidly becoming very popular. Research is being conducted to evaluate their adaptability and forage production as compared to Coastal bermudagrass.
In addition to hybrid bermudagrass, selections were made from common bermudagrass, and two varieties are most prevalent, Giant and NK-37. Although these two grasses generally produce less forage than the hybrids, they are seeded varieties and offer an advantage to owners of small acreages. These grasses do not spread as rapidly as the hybrids but have a more upright growth habit than common bermudagrass.
The following yield test results are from Bryan (sandy loam soil), Overton (sandy soil, East Texas), and Jackson (clay soil) Counties.
Table 1. Yield As A Percentage of Coastal Bermudagrass.Establishment
David Bade, Gerald Evers, S. Simecek, and M. Hussey.
Average Coastal 100 100 100 100 Tifton 146 134 146 142 Jiggs 125 144 120 130 Tifton 102 105 112 106 World Feeder 96 86 47 76
Establishment is a critical step. Considering the time, effort, and expense involved in establishing any forage, attention to details are important to be successful the first time. The ideal seed bed is smooth, firm, weed-free, moist, and fertile; is free of excess residue or "trash," compaction zones, and harmful insects and plant diseases; and has good soil structure.
For many people, grass is not a crop, it is just grass. But in order to get the full potential from any intensively managed crop, the crop should be planted on productive soils. Producers of hybrid bermudagrass should think of their "crop" as any other crop. Grass planted on low-potential, marginal soils will have a low yield potential. Adequate seedbed preparation is important to provide the proper environment in which to plant. Obviously, limiting factors such as stumps, pot holes, or salt problems due to poor drainage should be eliminated before planting. Initial tillage may include moldboard plowing, heavy disking with an offset disk, chiseling, or subsoiling. The soil should be worked with a disk to eliminate trash and reduce clod size. The seed bed should be as good as for any other crop. The seedbed should free of clods, firm, and not "fluffy." A fluffy seed bed will not allow water to move upward through capillaries in the soil. A weighted roller or "cultipacker" will do an adequate job. It is generally best to wait for a rain to settle the soil after initial preparation.
Producers who irrigate should prepare their land as they want it prior to planting. It should be uniform and set up in borders if flood irrigated. Flood irrigation is accomplished best when the soil is not level but uniformly sloping. Once established, it is difficult to "push" water through a stand of grass.
The land should be uniformly smooth to facilitate haying operations. Borders should be established under flood irrigation to match swathers and mower widths. Preplant fertilizer should be incorporated as recommended by a soil test. In the absence of a soil test, preplant-incorporate about 100 to 200 pounds per acre of a product such as 18-46-0, 11-53-0 (dry fertilizer), or 10-34-0 (liquid) on soils that are generally medium to high in phosphorus. In soils low in phosphorus, incorporate 200 to 400 pounds of the same fertilizers. Soils in areas of Texas that are generally medium to high in potassium do not need additional fertilizer for planting. However, on soils that are low in potassium, apply 100 to 200 pounds per acre of 0-0-60. (Additional information on fertility follows in the management section.) During the establishment stage, grasses need only small amounts of nitrogen. However, once the grass is rooted and begins to grow, the demand for nitrogen increases rapidly in order for the plant to produce proteins for continued growth.
Bermudagrass is commonly propagated by planting plant parts as rhizomes or sprigs (underground storage roots), stolons (above-ground runners), or tops (mature stems).Only common, Giant, and NK37 can be planted by seed. Sprigs or rhizomes are planted in late winter to early spring. Stolons and tops are planted in the late spring through early fall as moisture for "rooting" is prevalent. Stolons and tops are subject to desiccation or rapid drying in dry soils.
The entire rhizome or "sprig" is planted in a furrow immediately behind an opening device, covered, and rolled in a single operation. The depth of planting is determined by the availability of moisture and the texture of the soil. Placed too deep, the new growth may die. Placed too shallow, the sprig may dry out without irrigation. Under dryland conditions, 2 to 2 1 /2 inches deep is generally adequate. Under irrigation, plant at a depth of 1 1 /2 to 2 inches with occasional sprigs showing above ground. The "ideal" sprig is 5 to 6 inches long, planted with one end 2 inches deep and the other end at the soil surface.
If the soil is dry, water should be applied immediately after planting to prevent desiccation of sprigs. If the sprigs are planted in moist soil, irrigation may not be necessary or may be applied as needed.
Use fresh sprigs from a vigorous coastal field or a certified grower. Sprigs should be thick, tan to amber-colored, and crisp. After digging, it is important to keep sprigs moist and cool and to plant as soon as possible. Exposure of sprigs to the sun and wind after digging will increase desiccation and rapidly reduce their viability. If sprigs have been dug for more than 24 hours, they should be soaked in water for 12 to 15 hours before planting.
Table 2. Relationship of Exposure Time to Percentage of Sprigs Alive at Planting.
Exposure Time % Sprigs Alive Exposure Time at Planting No exposure 100 2 Hours, 9 a.m. - 11 a.m. 94 4 Hours, 9 a.m. - 1 p.m. 72 2 Hours, 12 noon - 2 p.m. 30 4 Hours, 12 noon - 4 p.m. 3 8 Hours, 9 a.m. - 5 p.m.
(shaded and moist)
Bermudagrass can be sprigged at many different rates. The faster a stand is desired, the more sprigs should be planted. The closer the spacing, the faster the sprigs will completely cover the area. The following table can help determine sprigging rates to use:
Table 3. Sprigging Rates.
Bushels/Acre Square feet for one sprig 5 8.7 10 4.3 20 2.1 30 1.5 40 1.1 50 0.9
Weed control is important to reduce competition for moisture, plant nutrients, and light. Weeds can be controlled either by mowing or through the use of herbicides. There are only three materials currently labeled for use in establishing new fields. Diuron (Karmex, Diuron, or Drexel Diuron are some product trade names) can be applied immediately after planting but before new growth emerges. For the herbicide to work properly, it should be "watered in" either by rainfall or irrigation. Diuron kills broadleaf weeds and some grasses before they emerge. The other herbicides are Banvel and 2,4-D, which are applied after weeds germinate. These products are subject to some restrictions in areas where cotton or other broadleaf crops are grown. Refer to the label for complete rate and timing instructions before using any pesticide.
Under dryland conditions, plant during the period when rainfall is most likely to occur, or shortly after a rain while the soil moisture is adequate.
Most failures in establishing hybrid bermudagrass are due to:
- Poorly prepared seed bed.
- Inadequate moisture at planting.
- Using desiccated or dried sprigs.
- Planting too few sprigs.
- Covering sprigs too deep.
- Not firming the soil around sprigs.
- Severe weed competition.
- Severe grazing before plants are established.
Planting Tops Rather Than Sprigs
Planting tops is somewhat different from planting sprigs in establishing bermudagrass. Sprigs are underground roots that are dug and planted. Tops are above-ground, green, mature stems. Tops, unlike sprigs, must develop roots at the nodes to become a plant. For a top (stem or runner) to root, it must be mature, about 6 weeks old, and 18 to 24 inches long, and it must have 6 or more nodes.
Planting tops allows producers to plant throughout the growing season as long as soil moisture is sufficient. Tops have been planted from late April through September. Fall-planted tops must have enough time to form roots and become well established before frost, or they will die during the winter. Tops planted in the late spring or early summer have the best chance to survive.
Planting tops has also allowed producers to establish a nursery and transplant runners to larger fields as they mature. This practice can decrease the cost of paying for complete sprigging and can be done by the producer.
The new Tifton 85 and Jiggs are easier to root by tops than other hybrid grasses.
The following suggestions will increase the chances of success:
- Plant 5 to 7 bales per acre.
- Cut the tops with a sickle mower, bale immediately, and plant as soon as possible before the bale becomes hot enough to kill the grass. With small plantings, "pitching" the newly cut grass on a trailer and spreading is adequate.
- Scatter and disk tops into moist soil before they wilt. Tops can die within minutes.
- Pack the soil immediately(using a roller) around new runners to prevent excessive moisture loss and ensure good soil contact.
Renovation of Hybrid Bermudagrass
Renovation is a practice or series of management practices to improve or "restore the vigor" of a field. Pasture renovation implies almost making the field new again. It includes such practices as soil testing and fertilizing according to the nutrients needed. It also implies several intensive series of practices to the extent of destroying the sod and replanting and everything in between. The intensity and level of renovation required depends upon the reason for decreased vigor, and the management goals and pasture usage of the producer. Table 4 summarizes renovation practices and what may be needed.
Although many reasons exist for pasture decline, the following symptoms would indicate that some kind of renovation should be considered:
- Reduced forage production.
- Thin stands with bare ground showing and a decrease in the number and vigor of rhizomes. Invasion of broadleaf weeds and undesirable grasses.
- Poor drainage.
- Poor water infiltration or penetration; soil compaction.
- Accumulation of nutrients in the top 1 inch of soil (such as phosphorus).
Table 4. Renovation Practices and Requirements
Minimum Renovation Extensive Renovation Soil testing Subsoiling or chiseling Fertilization Discing or plowing Weed control Replanting Prescribed burning Heavy fertilization
Soil testing and fertilizing should be the first practice in any renovation. High forage production will remove many soil nutrients, not just nitrogen alone. Hay production removes all the nutrients when the forage is harvested. For each 6 tons of hay removed, the soil must provide approximately 300 pounds of nitrogen, 60 pounds of phosphorus, and 240 pounds of potassium, plus sulfur, calcium, magnesium, all the other nutrients needed for plant growth. Continued hay removal will "mine" the soil until it is unproductive.
Nitrogen, sulfur, calcium, and phosphorus are the primary nutrients removed by grazing, but animal manure returns only a part of the minerals to the soil. With both commercial fertilizer and manure applications, non-mobile nutrients (such as phosphorus) tend to accumulate in the top 6 inches of soil. Since nutrients need to be dissolved in water for best uptake, during droughty periods root uptake is minimal from the soil surface.
Weed control will be part of any renovation program. Weeds compete with bermudagrass for water, nutrients, and sunlight. Weeds present during bermudagrass establishment prevent good stands and often result in plantings which take years or never cover completely. Thin, weak bermudagrass stands resulting from low fertility, drought, or heavy harvesting pressure cannot compete with weeds. Field experiments in Victoria County have shown that from 3 to 7 pounds of Coastal bermudagrass will be produced for each 1 pound of weeds controlled.
Prescribed burning during the dormant period prior to spring growth will remove excess dead forage; warm the soil; destroy some insects, winter weeds, and weedy grasses; and promote faster greenup. Disadvantages include fire hazards, the need for a burning permit, baring the soil for possible erosion, and removing protection from late freezes. Timing is critical and must be done after weeds have emerged but before bermudagrass greenup. Waiting too long delays bermudagrass regrowth and allows for emerging weeds to outgrow the grass. A suggested time for burning is about 1 week prior to the last average frost date. In Falls County, burning increased grass production by 143 percent while decreasing weed competition by 96 percent. The grass had a 4 percent increase in protein and 2 percent increase in mineral content (Ca,P,K,Mg) over non-burned areas.
Subsoiling chiseling, discing, and plowing are operations that will partially destroy the sod, but are used to manage bermudagrass pastures needing complete renovation. Subsoiling and chiseling will eliminate compaction layers, loosen the soil, increase air movement and water penetration, and decrease water runoff for increased root development. Intensive discing or plowing will incorporate organic matter, fertilizer, and lime (if needed in low pH soils); destroy grassy weeds; and replant bermudagrass. Often cultivation of hay pastures is desirable to smooth the soil surface, making haying easier. Any soil renovation work should be done in the early spring just prior to greenup and spring rains or irrigations. During droughty periods, major soil renovations should be delayed until there is adequate soil moisture to prevent killing bermudagrass rhizomes.
Replanting should be considered when there is an inadequate number of live rhizomes to rejuvenate the stand.
Management of Hybrid Bermudagrass
Of the factors that limit forage production, water is the most important. Without water, plants will not grow, no matter how much fertilizer is available. Fertility, particularly nitrogen, is the second-most-important limiting factor to production. From a practical viewpoint, water and fertility and their cannot be separated.
In comparison to other plants, hybrid bermudagrass is very water-efficient. The following chart (Table 5) depicts the relationship between the amount of water needed to produce a pound of dry matter.
The water efficiency of hybrid bermudagrass can be improved even more by the addition of plant nutrients or fertilizer. Since plants use nitrogen to build amino acids and proteins, the number of new cells that a plant can produce is directly related to the amount of nitrogen it is able to absorb. Up to a point, the more nitrogen and water available, the more the plant will grow. The following research was conducted in Crystal City, Texas, by Fisher and Caldwell.
Table 5. Effects of Nitrogen Rates on Percent Protein, Yield, and Inches of Water/Ton
The previous chart indicates three very important points that have been repeated in research throughout the South. Although the results will vary depending upon many factors, the general outcome will be the similar. As the rate of nitrogen increases, the percent crude protein and yield increase dramatically, while the amount of water used to produce a ton of forage goes down. With low nitrogen rates, a high of 17.6 inches of water is needed to produce a ton of dry matter. With adequate nitrogen, only 3.9 inches of water is needed to produce a ton of dry matter. Adequate nitrogen fertility is necessary to fully utilize the amount of water received by a crop. Water without fertility will not produce new plant tissue.
Warm-season perennial grasses utilize nitrogen, phosphorus, and potassium at a ratio of approximately 4-1-3. In addition, to produce 1 ton of dry forage, bermudagrass must absorb approximately 50 pounds of nitrogen per acre, 15 pounds of phosphorus, and 42 pounds of potassium. If these numbers are multiplied by the number of tons of forage desired, the product will equal approximately the pounds of nutrients needed. For example, for 4 tons of production, it will take approximately 30 inches of water during the growing season, and 200 pounds of nitrogen, 60 pounds of phosphorus, and 168 pounds of potassium.
Splitting the applications of fertilizer throughout the growing season improves efficiency, which means that a greater percentage of the nutrients, particularly nitrogen, is usually utilized by the plants.
It is important to soil test every 2 to 3 years, to determine if the natural mineral content of the soil is changing. In addition, many soils have the capability to provide some nutrients almost indefinitely. Fertilizer rates should be adjusted to maintain soil nutrients, without excessive buildup.
In summary, the advantages for fertilization include:
- Increased forage production.
- Improved forage quality, especially protein.
- Improved root system and sod density.
- Reduced weed competition.
- Reduced soil erosion.
- Improved water-to-yield ratio.
Stage of Harvest
Whether the grass is grazed by livestock or harvested mechanically, the stage or level of maturity of the plant tissue will also deter-mine its quality. Without proper harvest timing, high-quality forage will rapidly turn into "cardboard." Research conducted in Georgia on Coastal bermudagrass produced the following results (see Table 6).
Although the yield was higher for an individual cutting at 6 weeks, the amount of protein produced per acre was almost the same as the amount of protein produced after 3 weeks. In these tests, cutting twice at 3-week intervals would produce twice the protein and almost twice the forage per acre as cutting at 6-week intervals.
Hybrid bermudagrass can produce high quality forage. But, like any other crop, proper variety selection, adequate soil preparation for planting, correct planting, adequate fertility, along with wise irrigation management, and, finally, timing of harvest will result in high quality feed.
Table 6. Effects of Cutting Intervals on Quality of Yield.
Cutting Interval Yield
Tons per Acre
Matter per Acre
3 7.9 18. 5 2442 83 17 27 65. 2 4 8.4 16.4 2317 79 21 29.1 61.9 5 9.2 15.4 2329 70 30 30.6 59.3 6 10.3 13. 3 2292 62 38 31. 6 58 8 10.2 10. 7 1898 56 44 32.9 54.1 12 10.4 9 1612 51 49 33.4 51
The information given herein is for educational purposes only. References to commercial products or trade names is made with the understanding that no discrimination is intended and no endorsement by the Cooperative Extension Service is implied.
Educational programs of the Texas Cooperative Extension are open to all people without regard to race, color, sex, disability, religion, age or national origin.
Issued in furtherance of Cooperative Extension Work in Agriculture and Home Economics, Acts of Congress of May 8, 1914, as amended, and June 30, 1914, in cooperation with the United States Department of Agriculture. Zerle L. Carpenter, Director, Texas Cooperative Extension, The Texas A&M University System. 3M‹4-96