Davison, J., Powell, P., Schultz, B., Creech, E., and Singletary, L. 2011, Needs Assessment for Noxious Weeds in Churchill County: Part 1 of 5 - Problem Weeds, Approaches and Methods of Control, Extension | University of Nevada, Reno, FS-11-72

Introduction

This fact sheet is the first in a series of five publications designed to examine noxious weed issues that affect Churchill County. This publication discusses the results from a needs assessment conducted by the University of Nevada Cooperative Extension (UNCE) to identify problem weeds, the approaches and methods for control. Subsequent publications in the series will look at 1) problems and obstacles to weed management, 2) the spread, detection and prevention of weeds, 3) herbicides and the criteria used for their selection and timing of use; and 4) priority research and outreach programs.

Churchill County encompasses 5,023 square miles in western Nevada and lies approximately 60 miles east of Reno. Over 89 percent of the land in Churchill County is owned by the federal government. The only incorporated city in Churchill County is Fallon. Churchill County has a total population of 26,859 residents (2009), with 9,113 people residing within the Fallon city limits.

The Lahontan Valley, located in Churchill County, is the primary agricultural production area with 210,752 acres defined by the county as “agricultural” lands.These lands are classified into four use types, including cultivated (30,568 acres), pasture (8,776 acres), grazing (160,308), and meadow (~11,100), with water rights assigned to 39,877 acres. Most of the county lands are classified as rangelands or are covered with water.

In 2009, the U.S. Department of Agriculture reported that there were 529 farms in Churchill County, averaging 248 acres in size. The average farm in Nevada is nearly eight times as large as the average farm in Churchill County. Direct output value from the agricultural sectors in Churchill County in 2007 was $122.6 million dollars, of which $54.8 million was related to crop sales and $67.8 million to livestock or livestock product sales. The average economic multiplier value for the agricultural sector was 1.43, meaning that the agriculture sector generated an additional $52.8 million in economic activity for a total economic impact of $175.4 million dollars. In addition, during 2007 the agricultural sectors generated a total of 531 jobs directly tied to agriculture and an additional 446 jobs generated by the economic activity that the agricultural sector provides.

The county includes transportation corridors I-80, Highway 50, Highway 93 and two transcontinental rail lines. Churchill County receives irrigation water from the Carson and Truckee rivers. All of these corridors act as agents for the introduction and spread of noxious weeds. Several noxious weeds have established on lands adjacent to these rivers. These weeds, if not controlled, could dramatically reduce the yield and quality of the crops produced in Churchill County. Because most crops produced in Churchill County are used for livestock feed, reductions in livestock and livestock product sales are another possible result. Both will negatively impact the economic contributions that the agricultural sectors make to Churchill County.

Survey Methods

In 2008, University of Nevada Cooperative Extension (UNCE) faculty mailed a survey to all agricultural producers who reported at least $1,000 of annual income from agriculture. An electronic version of the survey was developed and offered to individuals with weed management responsibilities in all appropriate federal and state agencies within Nevada.

The 88-question survey targeted nine specific weed management issues and is being used to prioritize the most important educational and research programs for UNCE faculty. The results can also be used by other entities with weed management responsibilities to prioritize their activities.

The specific methodologies used for the original survey and analysis are available in UNCE Special Publication SP-10-03. Additional statistical analysis was completed to determine if the responses from Churchill County’s agricultural producers differed significantly from Nevada’s agricultural producers as a whole, and the public lands weed mangers’ responses. The results of this analysis are presented in the series of fact sheets outlined in the Introduction.

Results and Discussion

Problem weeds

Table 1 lists the most problematic weeds as prioritized by Nevada agricultural producers, Churchill County agricultural producers, and public land managers. In Churchill County the top five most problematic weeds in descending order were 1) puncturevine (goatshead), 2) sandbur, 3) hoary cress (short whitetop), 4) perennial pepperweed (tall whitetop), and 5) cocklebur. Churchill County agricultural producers’ priority listing of weeds was significantly different than those listed by Nevada agricultural producers and Nevada public land managers.

The most problematic weed listed by Churchill County producers was puncturevine. Nevada agricultural producers ranked it as No. 6 while public land managers did not list it at all. Sandbur was ranked second by Churchill County respondents and 11th by other Nevada agricultural producers. As with puncturevine, public land managers did not list sandbur as a problem weed. Both puncturevine and sandbur are primarily problems in agricultural fields and are more common in the warmer areas of the state. The most striking difference between Churchill County producers and the other groups responding to the survey was the lack of Nevada state recognized noxious weeds on the Churchill County lists. This may reflect the fact that Churchill County producers are much less dependent on rangelands for the production of their products and a majority of the noxious weeds legally recognized by the state of Nevada are associated with rangelands.

Approaches and Methods of Weed Control

A successful weed management program consists of: 1) preventing weed invasions, 2) weed detection, 3) weed control, and 4) the establishment of competing vegetation. Table 2 displays the ranked order in which all three groups placed these four tenets of a weed control program. The analysis of the data indicates that there were no significant differences between the three surveyed groups as to the most important approaches to a weed management program. The most probable reason for this result is that the basic tenets of a successful weed management program are well known and accepted by those experienced in managing weeds. When applied, they have a long track history of success and are the cornerstone of any educational program or weed management program. Therefore it is not surprising to see broad-based acceptance of these tenets by the groups surveyed. When queried about the most important method used for weed control, the responses of agricultural producers in Nevada and Churchill County were both significantly different than those provided by public land managers. There were no significant differences between the views of the two groups of agricultural producers surveyed. Table 2 presents the survey results concerning priority methods of weed control as ranked by the three groups in Nevada.

Weed control using herbicides was the highest-ranked method cited by Nevada agricultural producers and public land managers. It was ranked as the second most important method by the Churchill County respondents who listed controlled burning as the most important method by a small percentage. The biggest difference between Churchill County producers and the other groups was the ranking of tillage and mowing as the third most important techniques used for weed control. These results are not unexpected as Churchill County agricultural producers rely heavily on relatively small, intensively managed crop fields for the majority of their agricultural production and mechanical methods of weed control are commonly employed.

Planting competitive species to reduce weed competition and selecting favorable planting dates were ranked much higher by public land managers than both groups of agricultural producers. The use of insects was also ranked much higher by the public land managers. These results reflect the different management situations faced by the public land managers, including agency policies and mandates, as compared to agricultural producers in Nevada who favor more direct control techniques.

Additional Resources

Analytical Software. 2008. Statistix 9. User’s Manual. Analytical Software. Tallahassee, FL. 454 p.

Creech, E., L. Singletary, J. Davison, L. Blecker, and B. Schultz. 2010. Nevada’s 2008 Weed Management Extension Program Needs Assessment. University of Nevada Cooperative Extension Special Publication 10-03.

Duncan, C.L. and J.K. Clark (eds). 2005. Invasive Plants of Range and Wildlands and their Environmental, Economic and Societal Impacts. Weed Science Society of America. Lawrence, Kansas. 222 p.

Harris, T.R., and A.K Kerna 2009. An Economic Description of the Agricultural Sectors in Churchill County. University Center for Economic Development. University of Nevada, Reno. Department of Resource Economics Technical Report UCED 2009/10-01. 22 p.

Singletary, L. and M. Smith. 2006. Nevada Agriculture Producer Research and Education Needs: Results of 2006 Statewide Needs Assessment. University of Nevada Cooperative Extension Educational Bulletin 06-02. 118 p.

USDA. 2009. 2007 Census of Agriculture. Nevada State and County Data. Volume 1. Geographic Area Series. Part 28. USDA National Agricultural Statistics Service. Washington, DC.

*tables here

Learn more about the author(s)