Figure 1. One of the most excellent paddocks of bermudagrass, crabgrass, knotroot bristlegrass, and other warm season grass mixture in July 1991. This paddock produced 438 grazing days per acre from stocker steers and cow unit grazing, an average of 1.2 grazing days per calendar day on a yearlong basis. This paddock was diverse, having produced forage from cereal rye, annual ryegrass, volunteer natural annual winter grasses, winter season forbs, bermudagrass, crabgrass, Johnsongrass, bristlegrass, other summer grasses, and summer forbs all in one year. Rotational grazing was imperative to make this diversity work. Most of the knee high forage in this picture is the crabgrass.

Figure 2. Excellent crabgrass in a bermudagrass base pasture. This pasture was managed by light spring season disking, fertilization, and rotational grazing to cause this excellent crabgrass stand in the bermudagrass.

Bermudagrass (Cynodon dactylon) is often fair to poor quality during the last two-thirds of the growing season. Combining bermudagrass with higher-quality warm-season grasses such as naturalized crabgrass (Digitaria ciliaris and D. sanguinalis) and the Red River crabgrass variety (D. ciliaris) has been very successful (figure 1). Another acceptable choice is johnsongrass (Sorghum halepense).

Rotational grazing is imperative for successful bermudagrass and other warm-season grass mixtures and control of overgrazing, time and duration of grazing, residue height at the end of grazing, and recovery periods to allow proper regrowth. It is also important to use grazing to control seed set and maturity of some of the added grasses because they are more palatable, have higher concentrations of crude protein and digestible dry matter, and at times are available when bermudagrass is not. Rotational grazing has allowed ecological succession, which particulary in wet years has increased the quantity of knotroot bristlegrass (Setaria geniculata), Florida paspalum (Paspalum floridanum), indiangrass (Sorghastrum avenaceum), and switchgrass (Panicum virgatum), all of which are improvements over bermudagrass.

Bermudagrass is a good cow forage over extended periods. It is a tenacious, rhizomatous, and stoloniferous grass grown throughout the southeastern quarter of the United States and similar climates worldwide. These characteristics allow it to be manipulated to produce other forage or grain crops in the sod, with the bermudagrass remaining a functional stand.

To a lesser extent, warm-season legumes have been produced in relatively thin bermudagrass in humid regions. However, literature searches and agricultural researchers indicate that, heretofore, little technical work has been done on adding higher-quality warm-season grasses that can sustain a stand in a bermudagrass pasture to improve overall forage quality during mid- to late summer, fall, and early winter. This report is a brief summary of some of that work done on the Noble Foundation's Pasture Demonstration Farm.

The 'Midland' bermudagrass pasture used in this work was planted in 1965 and has been in excellent stand and vigor since 1966. From 1987 to 1989, twelve bermudagrass paddocks were planted to crabgrass, johnsongrass, and other forages.

Crabgrass was planted at 0.7 to 3.0 pounds of pure live seed per acre between April 25 and September 27. Most paddocks were planted twice to increase stand density and all were managed to produce seed for volunteer stands. Total crabgrass seeding rate was 1.0 to 4.0 pounds of pure live seed per acre. A common (naturalized) and Red River variety crabgrass were used, as was johnsongrass, with individual seeding rates ranging from 0.5 to 3.0 pounds of pure live seed per acre; total seeding rates, 0.5 to 3.5.

All seed were broadcast. Seed was trodden in with beef cattle during usual rotational grazing cycles. During planting, all paddocks received fertilization that was either starter fertilizer for rye and ryegrass planting or nitrogen topdressing for bermudagrass and other warm-season grasses. Fertilization for summer and winter forage was 100 pounds of actual nitrogen per acre per season plus phosphorus and potassium according to soil test results. Nitrogen for warm-season grasses, primarily bermudagrass, was applied in April, May, and June.

Crabgrass and johnsongrass established manageable stands on 100 and 83 percent of all paddocks planted, respectively. Crabgrass stands were rated good to excellent in 92 percent of the area. During 1991, paddock visual ratings showed crabgrass and johnsongrass stands were poor to excellent, with most poor stands still thick enough to volunteer and thicken. Over all paddocks, crabgrass was 45 percent of a full stand, which is good for quality summer forage, diversity, and higher-quality forage for cattle such as nursing calves using creep grazing. These mixtures function extremely well as creep grazing pastures.

Johnsongrass ranged from 0 to 37 percent of a full stand. Over all paddocks, it was 12 percent of a full stand. All but two paddocks had sufficient stands to be managed for volunteer and stand-density increase. There was sufficient johnsongrass forage in the whole grazing cell to make a substantial contribution to forage quality. Johnsongrass stands for this mixture were rated fair to excellent in 75 percent of the area. As time progressed, however, johnsongrass, Florida paspalum, indiangrass, and switchgrass declined to near 0 percent because of their inability to sustain stands at the grazing frequency and intensity needed to manage the primary bermudagrass base. Under normal climatic conditions, bermudagrass and crabgrass produce well on three- to four-week recovery periods, whereas johnsongrass tends to require four- to six-week recovery periods to persist.

Technical harvests were omitted to show relative yields of the mixture components. Visual appraisal indicated crabgrass composed over 50 percent of the forage available in some paddocks from July to September. Crabgrass was available as early as May in some paddocks. For eight years, the average daily gain of stocker steers on this unit was over 1.9 pounds per day and was made on high-quality winter and summer forages.

Some data show crabgrass averaged 21 percent crude protein and 66 percent digestible dry matter compared with 17 and 61 percent, repectively, for bermudagrass. Johnsongrass averaged 20 percent crude protein and 61 percent digestible dry matter compared with 19 and 64 percent, respectively, for bermudagrass. Knotroot bristlegrass averaged 12 percent crude protein and 55 percent digestible dry matter compared with 11 and 46 percent, respectively, for bermudagrass. All of the other warm-season grasses were generally greener and more succulent and palatable than bermudagrass. All of these data are from samples taken from midsummer to September, and each comparison is from separate samples taken close to each other to simulate grazing intensity.

One of the best mixtures of bermudagrass, crabgrass, knotroot bristlegrass, and other warm-season grasses produced 438 grazing days per acre from stocker steers and cow-unit grazing, averaging 1.2 grazing days per calendar day on a yearlong basis. This paddock was diverse, having produced forage from cereal rye, annual ryegrass, volunteer natural annual winter grasses, winter-season forbs, bermudagrass, crabgrass, johnsongrass, bristlegrass, other summer grasses, and summer forbs in one year (figure 1). Rotational grazing led to the diversity. Most of the knee-high forage in figure 1 is the crabgrass component.

Excellent crabgrass in a bermudagrass pasture in southern Oklahoma was managed by light spring-season disking, fertilization, and rotational grazing (figure 2).