The trial was replicated three times on a Winthorst fine sandy loam near Ardmore, Oklahoma. An excellent seedbed for planting very small-seeded field crops was prepared on a clean crop area by rototilling, hand raking, and dragging with a homemade iron drag. The proper amount of seed was mixed in dry sand that was a different color than the soil in the study area to provide bulk and aid in hand planting. The measured mix then was hand planted in broadcast and rowed treatments. Seed was from a field of a natural-composite ecotype of crabgrass (D. ciliaris) with moderate forage growth potential.

Planting was done on June 5 (two months past the normal early planting date) at 1 to 20 pound of pure live seed (PLS) per acre. Pounds of PLS per acre in broadcast treatments were 1, 2, 5, 10, and 20. Rowed plantings were in 7 ½-inch spacings at 2 or 5 pounds of PLS per acre.

Soil tests indicated a high availability of phosphorous and potassium, adequate calcium, and a pH of 6.0 to 6.2. The crabgrass was topdressed on June 28 with 68 pounds of actual nitrogen per acre about ten to fourteen days after initial seedling emergence when most of the seedlings were in the tillering and early runner stages.

Weeds were controlled with 2,4-D at 1 pound of active ingredient per acre. Armyworms were controlled with Dylox insecticide (trichlorfon) by using the label's method for hand spraying. Light irrigation was done to simulate a normal summer and keep the grass green and growing. In three months, a total of 5.7 inches of water was applied. The seven applications included 0.5 to 1.5 inches each.

Forage was harvested with a rotary blade/bagging mower. Residue was 3 inches high.

Figure 1. Early stand development influenced in part by seeding rate and planting method (broadcast versus rowed). These stands were present twenty-one days after planting and the first good rain: 2B, 2R, 5B, and 5R are 2 pounds per acre broadcast planted, 2 pounds per acre row planted, 5 pounds per acre broadcast planted and 5 pounds per acre row planted, respectively.

The initial stand was at the one- to four-leaf stage two weeks after the first good rain following planting and became well tillered two to three weeks later (figure 1).

There were five seedlings per square foot at the 1-pound broadcast rate and forty-three at the 20-pound rate (table 1). In general, the number of seedlings per pound of seed declined as rates increased, probably because of autoallelopathic response. The overall average was 3.9 seedlings per square foot per pound of seed, which correlates to about one established seedling per five live seeds planted. However, many more seedlings emerged after the count. Rowed plantings produced more plants per pound of seed than broadcast plantings at the same rate of seed.

These results are from a planting with two-year-old seed. Such aged seed germinates quicker and more uniformly than fresh seed. Results vary with field conditions.

Ground cover percentage increased sharply as the PLS broadcast rate increased from 1 to 5 pounds and stabilized at the 10-pound rate (table 2). There was no advantage in increasing the PLS broadcast rate beyond 10 pounds. Crabgrass at the 20-pound rate often wilted because of the high number of small plants with small root systems and because of other competition factors. Ground coverage of rowed grass increased much more rapidly than that of broadcast grass at the same planting rate.

At 1 to 5 pounds of PLS per acre, the practical seeding rates for pasture and hay meadow development, all areas were well covered by twenty to thirty days after seedling emergence. All seeding rates produced 100 percent stand cover by eight weeks after emergence.

Height of forage indicates its readiness for grazing or haying; 4 inches or taller is acceptable. All seeding rates produced such forage by thirty days after seedling emergence. The 5-, 10-, and 20-pound seeding rates produced grazeable forage by twenty days after emergence. Nitrogen fertilizer and water were applied about two weeks before plants in most treatments reached a grazeable height.

The 5- to 10-pound seeding rates produced 1,045 to 1,506 pounds of early forage per acre by July 20, which was about double that of the 1- to 2-pound rates (table 3). The rowed plantings had higher early-forage yields than broadcast plantings. Yields from the second harvest were similar, probably because all stands were similar by then. The 5- and 10-pound broadcast and the 5-pound rowed rate produced the best total yields, with a 14 to 26 percent advantage over yields from the other seeding rates.

Pounds of total forage per pound of nitrogen, without a check plot deduction, ranged from 43 to 56. The 68 pounds of actual nitrogen per acre was grossly inadequate to maximize first-year stands. In other research, first-year yields have ranged from 6,000 to 12,000 pounds per acre.

The first harvest was taken about thirty days after seedling emergence. The second harvest was taken thirty-six days after the first at an advanced stage of regrowth for grazing and a good stage for top-quality grass hay.

The forage was very lush at 16 to 20 percent dry matter in July and 24 to 29 percent dry matter in August. There was no chemical analysis of the forage.

If we assume a conversion of 10 pounds of grass per pound of stocker cattle gain, the first season's projected beef yields would have ranged from 292 to 374 pounds of beef per acre. At a rental value of $0.35 per pound of gain, the projected gross return per acre was $102.00 to $131.00. The 2-pound seeding rate costs about $67.00 per acre for first-year establishment and forage production (for seedbed, weed and insect control, and fertilizer).

Three deficiencies in this research need to be noted. First, the planting date (June 6) was about two months later than the normal earliest plantings in this latitude, which reduced production potential. Second, we used a natural composite rather than the selection that was 'Red River' crabgrass's origin. In other tests, 'Red River' crabgrass yielded an average of 20 percent more than the composite, so we assume yields would have been about 20 percent higher. Third, the nitrogen rates were not high enough to provide good nutrition the entire season.

Forage yields the second and subsequent seasons depend on management for volunteer crabgrass as well as other inputs.

The most practical seeding rates, considering seedling density, ground cover, grass height, and production, tended to be 2 to 5 pounds of pure live seed per acre (broadcast) and 2 pounds of pure live seed per acre (rowed plantings). The 2 pounds pure live seed per acre broadcast rate produced a satisfactory total yield but a low initial yield. By the end of summer, all seeding rates produced good stands. Seeding rates of 1 to 5 pounds of pure live seed per acre tended to be the most economical.

Seeding rates used in farm plantings have ranged from 1 to 10 pounds of pure live seed per acre. All are capable of producing first-year stands successfully with adequate production and seed for future volunteer stands. Stands that developed from seeds planted at 1 to 2 pounds per acre usually took much longer to cover soil and reach adequate grazing heights. Weed problems are usually more profound in plantings at the lower rates. Stands from seeds planted at 5 to 10 pounds per acre develop relatively quickly but are more expensive. Some dairymen use a 5-pound rate because they want a grazeable stand faster and probably can justify the seed cost. Plantings for soil conservation are likewise at 5 to10 pounds per acre for faster ground coverage.

In summary, 3 pounds of pure live seed per acre seems to be satisfactory and a good compromise between the best agronomic response and seed cost for establishment in farm circumstances.