Biological Control of Small Soapweed (Yucca glauca Nutt)

PROJECT BACKGROUND
Baldwin Cattle Company is a diversified farming and ranching operation located in Southwest Rooks County in Kansas. The operation covers 925 owned and rented acres, including 350 acres rangeland, 275 acres wheat, 185 acres fallow, 50 acres grain sorghum, 50 acres sorghum silage, and 14 acres alfalfa. The operation includes a 75 head registered Waygu cow herd with steers and heifers finished on the farm.

Waygu cattle were introduced into the United States from Japan in 1979. The breed boasts low birth weights and rapid growth. When compared to commercial English/continental breeds they exhibit higher levels of marbling, less external back fat, lower levels of LDL cholesterol. When cross bred to English/continental breeds the percent of cattle grading choice has increased.

Before receiving this grant Baldwin Cattle Company had maintained conservation practices by terracing erodible ground and practicing rotation grazing. As an indirect result of the selection of the Waygu breed of cattle, Baldwin Cattle Company experienced a significant reduction in the number of yucca plants on rangeland. Waygu were consistently observed grazing on yucca and effectively reducing yucca numbers. Since the introduction of this breed on the ranch, a steady decline in Yucca numbers has been observed by the producer.

PROJECT DESCRIPTION AND RESULTS
Small Soapweed (Yucca glauca Nutt) infests 75 to 90 percent of the rangeland in Rooks County with levels ranging from minor to serious. The plant tends to invade sandy sites, rough terrain areas, gullies, rocky and shale hillsides.

Cultural practices such as grazing management, burning, mechanical removal or similar practices have proven ineffective and/or not cost effective in reducing or preventing yucca populations. At the outset of the project treatment with Velpar L was the only labeled chemical control. Chemical control of yucca is very effective. However, due to the expense and labor requirements few land owners in the area are implementing chemical control measures.

Since Baldwin Cattle Company had observed the reduction in yucca on grassland grazed by Waygu, the objective of our project was to demonstrate and confirm the effectiveness of Waygu cross bred cattle as a cost effective, low management, biological control of yucca in rangeland.

The grant was used to set up a demonstration site to compare Waygu grazed range to that grazed by traditional English/continental cross cattle. In addition these sites were compared to a chemical treated area and a non treated/ non grazed reference site. An existing, yucca infested pasture was chosen for the project site. The site was divided into two grazing areas, one for Waygu and one for continental/English cross cattle of similar age, stocking rates, weight, etc. a chemical treatment site and non treated control site were selected in waste ground adjoining the pasture. This project required fencing to divided the sites, water development in each grazing area, purchase of chemical, labor for documentation of yucca number both prior to and after treatment in all treatment sites, determination of grazing capacity in each grazing site, and photo documentation.

People:
To begin the project we consulted with K-State Research and Extension to assist with planning and conducting the project. Randy Brown, K-State Research and Extension Specialist for crops and soils out of the NW Area office and John Forshee, County Extension Agent, K-State Research and Extension, Rooks County worked with us in this capacity.

In cooperation with this group, we determined where the cross fence should go, sites to count, and sites to use for chemical control and non treatment reference. Site 1, 2, and 3 were yucca infested areas where the English/continental cattle were grazed. Site 4, 5, and 6 were yucca infested areas where the Waygu cattle were grazed. Site 7 was the untreated reference site used to eliminate the possibility of some other pest, etc. causing damage to the yucca and skewing the research data. Site 8 was the Velpar L treatment.

I then built a cross fence to divide the existing pasture into the two grazing sites.

The Rooks County NRCS was brought in to determine the grazing capacity of each site utilized in the study in order to eliminate any differences in the grazing pressure on yucca due simply to incorrect stocking rates. Gary Long, NRCS technician and Darrel Beougher, Conservationist, conducted a grazing study and recommended grazing rates for each site. These recommendations were used to place cattle in each site.

In addition, the Rooks County NRCS developed the plans for the improvement of an existing pit pond for water on the site with the English/continental cattle and the development of a water site on the Waygu grazed site. This proved crucial to the study as any other existing water sites in the pasture went dry during the study leaving these two developed sites as the only water source.

Clifford Roy, Roy Crane and Dozer service, cleaned the existing pit pond and built the new one using a drag line.

The Palco FFA youth, Jennifer Benoit and Keith Darnall, along with instructor, Therean Towns were brought into the project to assist with initial and final yucca count as well as to provide some summer observations. These youth will also be writing up the results of this research as an ag-science project report on the state level. Training was provided to these youth by the Rooks County Extension Service. With this training, they conducted the initial count and took photographs of the site at the beginning of the project on May 19 in cooperation with County Extension Agent, John Forshee. In addition, they made observations in July, August, and September. A final observation was made after the cattle were removed at the end of October. A final count and photographs were gain taken as a cooperative effort between the Palco FFA and the Rooks County Extension Service on November 18.

Results:
All sites were counted on May 19 using a 100 foot transect line method. All sites were referenced to existing landmarks within the pasture to insure that the exact same site was measured for the final count. Site 8 was also treated with Velpar L on that date. Cattle were introduced into the site on May 1 and removed on November 1. Final yucca counts were taken on November 18.

Sites 1, 2, and 3 had 7, 6, and 7 yucca per 100 foot of transect line respectively on May 19. All of these yuccas appeared healthy with some flowering. A few flowers had been eaten on by the English/continental cattle.

Sites 4, 5, and 6 had 12, 15 and 7 yucca respectively per 100 foot of transect line on May 19. Again, all of these yuccas appeared healthy with some flowering. A few flowers had been eaten by the Waygu cattle.

Site 7 had 19 yuccas per 100 foot of transect line on May 19. This population was very healthy in the waste grass land.

53 yuccas were treated within an area at sight 8. No transect line was used here as all yucca were treated in an area approximately 50 feet by 50 feet.

Observations made throughout the summer affirmed what we found in the final observation.

On final observation on November 19, sites 1, 2, and 3 had 7, 6 and 7 yucca respectively. Pictures will confirm that these yuccas all appeared healthy. The flowers had been eaten off the top but the seed stalks remained.

Sites 4, 5, and 6 had 11, 14 and 11 healthy yucca remaining but the amount of grazing was considerably higher. Note the pictures show few if any seed stalks remain. In addition, the center of the yucca had been eaten in many cases. From past experience in other pastures we would expect a portion of these yuccas to die throughout the winter. We feel that we are seeing some initial signs of this at the November count with some browning of lower leaves on many plants.

Site 7 showed 19 extremely healthy yuccas with seed stalks and pods in tact.

Site 8 showed the effectiveness of Velpar with 100 percent of the plants showering yellowing at the November counting.

We really saw what we expected. We did expect a little more grazing damage on the Waygu side based upon what we have seen in past years. However, due to a warm fall we saw more fall growth on the yucca than would be expected in normal years.

Discussion:
Based upon this research and our observations over the past years, we would conclude that Waygu cattle are effective in reducing yucca numbers. If we had the project to do over, we would do it as a longer term type of study to look at it more than two to four years. With all the plans in place we plan to do just that. We will stalk the pastures accordingly again the next two years and do initial and final counts as we did in this project. We expect to be able to show more graphic results with a long term study.

These results were seen with only half blood cows. We feel that a producer could utilize a Waygu bull to not only reap the carcass benefits but also to bring yucca infestations under control.

We plan to use this information not only as a range management tool but as a marketing tool to promote and sell Waygu replacement females and bulls to other potential Waygu breeders and to commercial cattle producers.

OUTREACH
The results of this study are currently being written for inclusion in the Rooks County Extension Ag Newsletter for December mailing. A news release has been sent to the High Plains Journal.

We are sending a copy of this report and news releases to the American Waygu Association for their use in promotion and marketing.

The Palco FFA participating in this project will be writing the project up as an Agri-science project to be entered in their state competition and shared with other Ag science classes across the state of Kansas.

As we continue this project, this site will be used as a site for a range management and livestock waste management tour to be conducted by the Rooks County Extension in 1999. In addition, we will participate in the Rooks County on farm demonstrations group to share our findings with other producers doing on farm studies.