Davison, J., Powell, P., Schultz, B., and Singletary, L. 2012, Needs Assessment for Noxious Weeds in Churchill County: Part 4 of 5-Criteria for Herbicide Use and Selection, University of Nevada Cooperative Extension

Introduction

This fact sheet is the fourth in a series of five that reports the results of a needs assessment survey completed by faculty in University of Nevada Cooperative Extension (UNCE). The survey attempted to identify the major issues related to the management and control of weeds in Nevada. Weeds are consistently identified as a major threat to agricultural production and natural resource values in Nevada.

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 city limits.

The primary agricultural production area is the Lahontan Valley where the county has defined 210,752 acres as “agricultural” lands. They classified these lands into four use types. The four types include; cultivated (30,568 acres), pasture (8,776 acres), grazing (160,308), and meadow (approximately 11,100). Water rights are assigned to 39,877 acres of these lands. Most of the lands in the county are classified rangelands or are covered with water (94 square miles).

There were 529 reportable farms in Churchill County in 2009 averaging 248 acres in size. The average farm in Nevada is nearly eight times as large as the average-size farm in Churchill County. The total direct output value from the agricultural sectors in Churchill County in 2007 was $122.6 million 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. 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 several transportation corridors including Interstate 80, Highway 50, Highway 93 and two transcontinental rail lines. Churchill County also receives irrigation water from the Carson and Truckee rivers. Both rivers have established populations of several noxious weeds on lands adjacent to these rivers. All of these corridors act as agents for the introduction and spread of noxious weeds. These weeds, if not controlled; poses the real possibility of dramatically reducing the yield and quality of the crops produced in Churchill County. Because a majority of the crops produced in Churchill County are used as livestock feed, reductions in livestock and livestock product sales are another possibility. Both factors will negatively impact the economic contributions that the agricultural sectors make to Churchill County.

Survey Methods

In 2008 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 charged with weed management 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 and the public lands weed mangers responses.

The results of this analysis are presented in a series of five fact sheets including the following themes: 1) problem weeds, the approaches and methods used for their control; 2) problems and obstacles to weed management; 3) the spread, prevention and detection of weeds; 4) herbicides and the criteria used for their selection and timing of use; and 5) priority research and outreach programs.

Results and Discussion

Herbicide Selection Criteria

The survey allowed respondents to rank 14 different criteria related to the most important items used to select a herbicide (Table 1). The statistical analysis resulted in no overall significant differences between any of the groups regarding the criteria they used to select a herbicide for a specific weed control project with a 90 percent or higher level of confidence. However, there was some differences that are illuminating.

All three groups ranked “specific weeds controlled by the herbicide” as the most important selection criteria when choosing a herbicide (Table 1). Both agricultural groups ranked “familiarity with the herbicide (used it before)” as the second most important criteria while the public land managers ranked that criteria as the seventh most important. The difference may be tied to the fact that producers generally grow a limited number of crops and commonly use the same herbicides on them. Public land managers deal with a much broader spectrum of weed species and sites, broadening the spectrum of herbicides to consider. Public land managers also ranked “applicator safety” as the fifth most important criteria as compared to Churchill County growers (eighth) and Nevada producers who ranked it 10th. This may be related to a lower level of use or familiarity related to pesticide use and the high priority or training all state and federal agencies give to safety in general. There was general agreement among all the groups for the next four or five criteria. Weed size and growth stage was ranked as the second most important criteria by public land managers and third by producers. Potential injury to crops or non-target plants was tied for the second most important criteria by public land managers and only slightly less important (fourth) by agricultural produces in Nevada and Churchill County. Criteria related to environmental factors (“air conditions, longevity of the herbicide in the soil and potential to contaminate ground or surface water”) were ranked by all groups as generally moderate in importance. “Herbicide availability” was ranked as slightly higher criterion by both groups of agricultural producers than public land managers, but all groups generally agreed on the four lowest-ranked criteria as displayed in Table 1.

Table 1 (Part 4). Criteria for herbicide selection on lands managed by Nevada’s agricultural producers (n=746), Churchill county’s agricultural producers (n=164) and public land weed managers (n=52) in Nevada. The values represent the percentage of respondents who indicated moderate to high importance. Items are sorted in order of decreasing importance to agricultural producers.

*Table here

Timing of Herbicide Applications

As with the criteria used to select herbicides, the survey results and analysis did not detect any significant differences between agricultural producers and public land managers. In fact there was remarkable agreement in the rankings between all groups surveyed (Table 2). The most important criteria selected by all groups were the size or growth stage of the target weed. More than 80 percent of all groups ranked this as a moderate to high level of importance. The groups also strongly agreed that: environmental conditions, weed density, potential for the weeds to reduce growth of crops or desirable plants and the crop or desirable plant size or growth stage were included in the top five most important criteria. Lower ranked criteria included: recommendations from consultants or salesperson, number of days after planting, specific calendar dates, pressure from outside groups and the Farmer’s Almanac.

Table 2 (Part 4). Criteria for timing of herbicide applications on lands managed by Nevada’s agricultural producers (n=746), Churchill County agricultural producers (n=164) and public land weed managers (n=52) in Nevada. The values represent the percentage of respondents who indicated moderate to high importance.

*Table here

Conclusions

In almost all instances the survey respondents were in close agreement regarding the criteria important in the selection and use of herbicides. This indicates that the respondents have been receiving consistent information from Extension and others providing educational programs and herbicide use recommendations for weed control in Nevada.

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.

Learn more about the author(s)