- Animals: sheep
- Animal Production: feed/forage, feed additives, free-range
- Education and Training: demonstration, extension, farmer to farmer, on-farm/ranch research, participatory research
- Pest Management: biological control, field monitoring/scouting, physical control
Medusahead (Taeniatherum caput-medusae) is an invasive noxious annual grass of Eurasian origin that has infested 5 million acres of rangeland in California and millions more in other western states. Severe medusahead infestations result in a loss of $20/acre/year in grazing value, reduced recreational value, and extremely low biodiversity. Medusahead threatens the ecological and economic integrity of rangeland ranching, one of the major industries of California. Recent research at the University of California at Davis has demonstrated that properly timed high-density grazing can effectively control medusahead. Common methods used to achieve high density grazing include fencing, herding and attractants. The purpose of this project is to test the use of molasses sprayed on medusahead as an attractant to increase the forage utilization by sheep. In late-April of 2006 we sprayed 100 ft2 plots of medusahead with one of three different concentrations of molasses. The percent cover of individual plant species and forage biomass was monitored before and after the molasses application. The monitoring data indicated that all concentrations of molasses did not result in greater forage utilization than the control, or untreated areas. After this disappointing result, we decided to try a different approach by first training the sheep to seek molasses. In April 2008, we used a training method developed by Kathy Voth with the BEHAVE program at Utah State University to train the sheep to be attracted to molasses. We then sprayed medusahead infested areas of a rangeland grazed by the trained sheep. Once again the molasses treatment failed to attract the sheep to consume the medusahead.
Medusahead (Taeniatherum caput-medusae), an invasive noxious grass native to Eurasia, infests an estimated 5 million acres in northern California. Pellant and Hall (1994) determined that 3.3 million ac of BLM lands were cheatgrass or medusahead monocultures; nearly 14 million acres were infested with one or both; and an additional 62 million were at risk of invasion. Medusahead is perhaps the only grass that invades cheatgrass stands (Young and Evan 1970), partly due to its ability to germinate early and grow roots under cold temperatures earlier and deeper than cheatgrass and native perennials (Hironaka 1961, Harris 1977).
By 1999 medusahead was distributed over 5 million acres in northeastern CA (Miller et al. 1999). It first invaded Glenn and Colusa counties in the 1950’s. Although Young (1994) reported that medusahead had probably already invaded all suitable sites in CA, it has continued to expand steadily. Producers and Farm Advisors in Monterey and San Luis Obispo counties report that medusahead is a recent and major problem in their rangelands (R. Larsen, personal communication).
Medusahead is high in silica, unpalatable to livestock and wildlife, and slow to decompose. This results in heavy accumulation of a thatch that effectively inhibits other species and leads to a near monoculture. Once medusahead matures, it is rejected by grazing animals, birds and rodents, rendering pastures useless for livestock and wildlife. This translates into a permanent 75% loss in livestock carrying capacity (George 1992), equivalent to a loss of $20/acre/year.
The beef and sheep industry of California produced cash receipts for $1.6 billion or 22.9% of all livestock and dairy in 2003 (California Agricultural Statistics 2003). Most of the beef and sheep production in the state depends on the calf and lamb crops that are produced on rangelands and pasture. Rangelands of California are the primary forage source for the cow-calf operations that supply calves and yearlings to feedlots in California and other states. Cattle ranches are predominantly family-run cow-calf operations (Anderson et al. 2002). Thus, medusahead threatens the ecological and economic integrity of rangeland ranching, a major industry already under threat due to the demography of ranching families, and the competition from alternative, high-dollar value uses of land such as development and vineyards.
In a survey of ranchers in Solano, Yolo and Napa counties, intensive grazing was identified as the most favorable method of controlling noxious weeds (Doran 2002). Burning, herbicides and mowing are also methods used to control medusahead and other noxious weeds, but these methods were identified as less favorable by ranchers because of their difficulty, high cost, and impracticality of use in rangeland systems. Intensive grazing is viewed more favorably by ranchers for several reasons listed below:
-Intensive grazing does not require expensive external inputs since ranchers already have livestock for grazing.
-Ranchers are familiar with intensive grazing practices.
-Intensive grazing is more feasible than other weed control methods on extensive rangelands with variable topography and vegetation.
-Intensive grazing does not require special permits.
-Intensive grazing utilizes forage that would otherwise be lost if burned or killed with herbicide.
-Intensive grazing can be incorporated into the normal herd management and rotations.
In response to the survey and growing state-wide interest in controlling medusahead, a research mission was established by campus and county-based UC researchers to address the use of intensive grazing for controlling medusahead. Research has since shown that properly timed high density grazing can provide over 90% control of medusahead. Our research is now focusing on the mechanics of applying high density grazing on actual range situations through practical and feasible livestock management practices.
Anderson, M.A., S.C. Blank, T. LaMendola and R.J. Sexton. 2002. California’s cattle and beef industry at the crossroads. California Agriculture, 56(5):152-156.
Doran, M.P. 2002 Survey results. ANR-UCCE Solano, Yolo & Napa Counties. Local Fodder July 2002.
George, M.R. 1992. Ecology and management of medusahead. Department of Agronomy and Range Science. Agricultural Experiment Station. University of California, Davis, Range Science Report: 1-3.
Hironaka, M. 1961. The relative rate of root development of cheatgrass and medusahead. Journal of Range Management, 14(5):463-467.
Miller, H.C., D.W. Clausnitzer, and M.M. Borman. 1999. Medusahead. In R.L. Sheley and J.K. Petroff, editors. Biology and Management of Noxious Weeds. Oregon State University Press, Corvallis, Oregon.
Pellant, M. and C. Hall. 1994 Distribution of two exotic grasses on Intermountain rangelands: status in 1992. In: Monsen, Stephen B.; Kitchen, Stanley G., compilers. Proceedings – ecology and management of annual rangelands; 1992 May 18-22; Boise, ID. Gen. Tech. Rep. INT-GTR-313. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station: 109-112.
Young, J.A. and R.A. Evans. 1970. Invasion of medusahead into the Great Basin. Weed Science, 19:89-97.
Young, J.A. 1994. Ecology and Management of Medusahead (Taeniatherum- Caput-Medusae Ssp Asperum [Simk] Melderis). Great Basin Naturalist 52:245-252.
The objectives of this project are to test the effectiveness of three different concentrations of molasses in attracting sheep to consume medusahead and extend the results of the trial to local livestock producers and rangeland managers. Four treatments consisted of the following molasses concentrations and applications:
1. Control; 100% water applied at 50 gallons/acre
2. 12.5% molasses, 87.5% water applied at 50 gallons/acre
3. 25% molasses, 75% water applied at 50 gallons/acre
4. 50% molasses, 50% water applied at 50 gallons/acre
We hypothesized that the impact of sheep on medusahead would be greater than in the control plots and would increase as the molasses concentration increased.