Crabgrass as a Forage

by R.L. Dalrymple

Crabgrass is the common name for a group of grasses within the genus Digit aria known by almost everyone as a weedy plant. Its reputation as a pest is earned by its success as an invader in gardens, yards, and cultivated summer crops. However, these characteristics and its quality under proper cultural practices make crabgrass an excellent forage plant. Crabgrass is a relatively high quality forage in the summer when most forages are low quality. Crabgrass forms a good sod and can provide complete ground cover.

Cattle grazing on crabgrass at the Foundation's Pasture Demonstration farm.

Crabgrass was introduced into the U.S. by the government in 1849 as a forage plant, and there have always been a few producers who have used crabgrass as forage either accidentally or on purpose. The first known research effort evaluating crabgrass as a forage began at the Noble Foundation in 1972 with a naturalized stand on our Pasture Demonstration Farm (PDF). This research culminated in the development and release of the variety Red River in 1988.

A Demonstration
One pasture on PDF has been double cropped with winter pasture rye and crabgrass for 26 years without failure of either crop. Our primary approach has been to minimum-till farm the pasture for cereal rye and volunteer crabgrass. The cereal rye is used for fall and spring pasture. The crabgrass is used for summer pasture and/or hay. Initially, we used the "weedy" crabgrass ecotype naturalized for that site. Since 1990 we have used the Red River variety.

The demonstration has been grazed by beef cattle of several classes, including cow/calf units, replacement heifers, first calf heifers, stocker steers, and stocker heifers. Because crabgrass is of such high quality, the higher value weight gains of stocker cattle are probably the best way to market the forage.

Table 1 shows production on the pasture in years when only stocker cattle were grazed prior to the seeding of Red River crabgrass.

This production is about three times what we would expect from a cow/calf operation on fertilized introduced grass in this region. Our data shows the double crop to produce about 60 percent more forage than single cropping either rye or crabgrass.

Crabgrass can also be managed as a single crop forage. However, few graziers do so because it is so easy to employ the forage in a double crop, mixture, or other multiple use fashion. Our demonstration of single crop crabgrass has produced an average equivalent of 4,273 pounds per acre dry weight forage, 237 stocker cattle grazing days per acre, and 431 pounds of beef gain per acre. Our highest beef production from a single crop, native crabgrass pasture was 593 pounds per acre.

Crabgrass Management Highlights

• Crabgrass produces best on well-drained sandy soils, but is also very successful on loam and silt loam soils. It is less productive on clay loam soils, especially those with poor drainage.
  
  
• Proper renovation (tillage) in the off season can double or triple crabgrass yields relative to no-tillage systems.
  
  
• Crabgrass is nitrogen loving. It produces about 25 pounds of forage per pound of nitrogen applied. It also responds well to nitrogen supplied from legumes.
  
  
• Crabgrass is usually second only to Johnsongrass in palatability trials.
  
  
• Crabgrass can be established by overseeding into winter annual grasses and legumes from late winter to early spring as well as on good seedbeds from spring to June.
  
  
• In the first year of crabgrass production from seed, forage yields increase as seeding rates rise up to 10 pounds per acre. However, seeding rates of about three pounds per acre generally seem adequate.
  
  
• About 75 percent of crabgrass seedlings emerge from less than 3/4-inch soil depth in optimum conditions.
  
  
• Red River crabgrass can yield more than 12,000 pounds dry matter per acre.
  
  
• Individual average daily gains as high as 3.57 pounds have been produced with steers grazing Red River crabgrass. We expect average daily gains of about 1.8 pounds on crabgrass pasture under good management.
  
  
• In clipping trials, we have found crabgrass yields to be 32 percent higher under simulated rotational management when compared to continuous grazing.