The demonstration field has been small-grain winter pasture and planned volunteer crabgrass double cropping for twenty-four years. During the winters of 1994-95 and the summer of 1995, it was managed as a 'Maton' cereal rye and planned volunteer 'Red River' crabgrass double crop. All forage was grazed. The following is a summary of the forage and stock management.

The 1994 crabgrass crop was grazed completely by August 31. We had never applied Roundup herbicide to the area before, but we did so on September 12, 1994, to control invading bermudagrass from fence rows and water spillways and preserve the integrity of the crabgrass work.

On September 20, 1994, about two weeks later than this type of planting is normally done, the area was disk harrowed about 4 inches deep, rolled (packed), drilled to rye, and rerolled. The second rolling was a trial to determine if firming would aid cereal rye stands and production. It did not. We normally disk, roll, and drill in tandem to accomplish the planting with one tractor trip, which is cheaper and faster.

'Maton' cereal rye, a good forage, was drilled in 7 1/2-inch rows at 110 pounds of pure live seed per acre. Fertilizer (N-P₂O₅-K₂O at 12-40-0 pounds per acre) was banded in the row with the rye seed. The rye emerged soon and was topdressed with 100 pounds N per acre on September 29 for fall-phase pasture and again at 100 pounds N per acre on February 21 for spring-phase pasture. We judge these rates as upper moderate for our climate and for 'Maton' rye capabilities. Seed, fertilizer, and fertilizer applicator costs for the rye pasture were $90.85 per acre.

At the end of spring rye grazing on April 26, 1995, the pasture was disk harrowed about 3 inches deep and rolled to promote the planned volunteer crabgrass stand and its early and total production. This renovation was done in a tandem single-trip operation.

The crabgrass was given a preemergent topdressing at 100-0-62 pounds of N-P₂O₅-K₂O per acre. Fertilizer and application costs were $43.43 per acre. Crabgrass also was sprayed with 2,4-D amine at 1.1 pounds per acre plus surfactant for spiny pigweed control. Spray solution cost was $5.36 per acre. On average, we spray this crabgrass pasture once every three years ($1.78 per acre per year).

Anhydrous ammonia as a nitrogen source is less expensive than ammonium nitrate (34-0-0), but we have not estimated equipment input costs. Graziers may choose to use different fertilizer rates for their production goals; lower rates mean less production, while higher ones, within reason, mean more. Phosphorus applied at rye planting and potassium applied at crabgrass fertilization serve yearlong needs.

Production averages and ranges in this syndrome may be of interest. A twenty-one-year average showed crabgrass produced about 3,075 pounds of dry-weight forage after winter pastures produced 4,285 pounds per acre, for a total of 7,361 pounds of dry-weight forage per acre. The yearly per-acre total of fertilizer was 264 pounds of N, 51 pounds of P₂O₅, and 32 pounds of K₂O for essentially three forage crops that produced about 28 pounds of high-quality grass per pound of N.

A grass-to-beef conversion with stocker cattle is about 10 : 1, depending on the grass and the stocker cattle. Sometimes, with lightweight cattle, it can be as low as 6 : 1 on high-quality grass.

The poorest production on record was during the 1979-80 winter and 1980 summer, which was the hottest and driest on record in southern Oklahoma. The winter pasture produced about 3,850 pounds per acre. The crabgrass phase produced about 1,470 pounds per acre, for a total of 5,260 pounds per acre. The yearly per-acre total of fertilizer was 85 pounds of N, 56 pounds of P₂O₅, and 0 pounds of K₂O on the winter pasture. Fertilizer was not applied to crabgrass in the drought of 1980; production was finished by July 1 and equaled 62 pounds of grass per pound of N, with crabgrass nourished by residual fertilizer, which it uses efficiently to produce well.

The highest production on record showed that the double-cropped crabgrass produced 6,440 pounds per acre following winter pasture that produced about 3,250 pounds per acre, for a total of 9,690 pounds of forage per acre. The yearly per-acre total of fertilizer was 110 pounds of N, 0 pounds of P₂O₅, and 0 pounds of K₂O. Both forages fed somewhat on residual fertilizer and yielded 88 pounds of grass per pound of N.