By Christine Gelley
Crabgrass is a hated weed in the world of turfgrass management and often seen as a plague in lawns and on sports fields. Despite it’s bad reputation as a weed, crabgrass was originally introduced to the United States for livestock and can be a friendly forage.
Dispelling a Bad Rep: Crabgrass possesses traits that allow it to excel as a weed, but those same traits implemented in the right place at the right time can be used to your advantage as a livestock forage. It is fast growing and fairly easy to establish. It is tolerant of foot traffic and close harvest heights. It provides excellent nutritive value and is actively growing when cool-season grasses like tall fescue, orchardgrass, and ryegrass go dormant.
Each year crabgrass works toward accomplishing the goal of all living things, to reproduce, and if it had a life motto it might be something like: “Life is short, so live it!” Crabgrass is an annual warm-season grass that reproduces by seed and spreads with stolons. The vegetative period of growth can be prolonged through rotational grazing and seed head clipping.
It begins germinating when soil temperatures reach 58°F and can thrive while other species lay dormant in the summer heat. It has few known pests and pathogens and can grow well on marginal sites. Intentionally utilizing crabgrass as forage could lead to opportunities for extending the grazing season and producing high quality hay during the warmest periods of temperate summers.
History and Progress: In 1849, crabgrass was introduced by the U.S. government for use as forage and has since spread across the nation. The Noble Foundation has been conducting research on crabgrass as forage in Ardmore, Oklahoma since the 1970s. In the 1980s the Noble Foundation released the first cultivated crabgrass variety, ‘Red River’, later followed by the variety, ‘Quick N’ Big’.
Universities and producers have also experimented with these varieties and have found that they produce forage of excellent nutritive value with high intake and rate of gain by livestock, particularly beef cattle. Under good growing conditions and management to reduce seed head development, values of up to 15% crude protein (CP) and averages of 10% CP from June through September have been observed for crabgrass ‘Quick N’ Big’.
Site Preparation: Well drained soil is best for crabgrass. It is tolerant of soils with 5.5-7.5 pH. Seed should be broadcast on a tilled soil surface or drilled at ¼ inch at a rate of 3-5 pounds of pure live seed per acre and cultipacked.
If crabgrass has established well and is allowed to reseed for the next season, lower seeding rates may be effective in subsequent years. With adequate moisture, seeds will germinate in a few days and be ready for grazing in about 30 days. Crabgrass is highly responsive to nitrogen, so split applications can generously increase dry matter yields.
Grazing and Hay: Rotational grazing has proven more efficient for dry matter production and animal gains than continuous grazing. If managed for hay, crabgrass should yield at least two substantial harvests per year. Care should be taken to keep crabgrass vegetative during production through removal of seed heads, thereby preserving good nutritive value throughout the summer.
Defoliation heights can be tolerated to as low as 3 inches, stands can be ready to graze at 6 inches, and cutting for hay should occur during early boot or about 18 inches high. Crabgrass hay may take longer to cure than other popular forages. Dry matter yield typically ranges from 2-5 tons/acre. It can be incorporated in crop rotations with other annual crops, used as an emergency forage, or allowed to intermix with other forage species.
Be aware that grazing soon after a nitrogen application could result in nitrate poisoning if conditions are conducive. Fast growing forages including crabgrass, corn, fescue, oats, pearl millet, rye, wheat, and others quickly take up applied nitrogen. When growth slows, nitrate uptake continues, but conversion to amino acids and proteins slows. The concentration of nitrates in the plant can rise to dangerous levels during times of drought or extensively cloudy weather that follows a nitrogen application. Split applications of nitrogen and limited grazing during concerning conditions can prevent nitrate poisoning.
Crabgrass has no history of harmful enzymes or endophytes and can be used for all classes of livestock. Most research has been conducted for beef production, but it can also be used for horses, sheep, goats, hogs, chickens, and exotic animals.
Availability: It is unlikely that you will find crabgrass seed on the shelves of your local co-op, but it can be ordered from the supplier and variety developer, R.L. Dalrymple of Oklahoma or associated dealers. Depending on the variety, seed costs range from $5 to $8.50/lb. Depending on your seeding rate, total costs range from $15 to $42.50 per acre for seed.
Be sure to select improved varieties, not wild type crabgrass. Improved varieties are selected to produce taller plants with larger leaves for increased ease during harvest and grazing.
The Other Side of the Fence: Your neighbors may think you are crazy if you decide to grow crabgrass on purpose. Despite what your neighbors think, taking the opportunity to boost forage production, animal gains, and profitability is not crazy. Crabgrass has potential to become a valuable tool in your forage system. So while your neighbor pursues the perfect lawn, you can continue to pursue offering the perfect forage to your livestock, maybe including a component with a bad reputation- Crabgrass.
Source: osu.edu