Grazing Lambs to Manage Weeds and Grass in a Cold Climate Vineyard

WORK ACTIVITIES
Activity; Timing; Cost

Manage weeds in the control area by spraying with Roundup or Rely; April 16, June 6, July 15, Aug 20, Sept. 10; Chemical $60, Labor—9 hours $135

Mowing in control area; April 25, May 25, June 14-15, June 29, July 16; Gas, oil—16 gal $48, Diesel—10 gal $30, Labor--7.5 $113

Soil test X 4; May 3; $54

Prepared protective wire mesh cages for newly planted replacement vines, install cages; May 3; Wire—(5 at $30)$150, Labor—5 hours $75

Purchase and install Electronet, set up water tank and water system; June 4; Electronet--$439, Hose $60, Float $20, Labor—2 hours $30

Contact livestock owner and Extension livestock educator to arrange for lambs and determine stocking rate; June 4

Extension educator examined site and inventoried types of plants/weeds; June

Lambs delivered, 25 crossbred 32.8 lb average; June 14; Trucking $25

Determined damage to plants and contacted owner to recover the lambs; June 26

Lambs removed; June 27; Trucking $25

Record keeping, reports; April-September; 4 hours $60

RESULTS
The project was ended 13 days after the lambs arrived. They were content to graze the lush grasses for the first few days but quickly found the low hanging grape vines and began eating them. That first pruning was acceptable but the taste of the grape leaves must have been enticing since they began to pull down the cordons to get at higher leaves. In some cases we observed one pulling down the cordon and others reaching even higher to get at more leaves. Sometimes several were pulling on a cordon at one time creating considerable pressure on the junction of the cordon with the trunk and breaking it from the trunk. The result was broken cordons on nineteen plants, usually multiple branches, and too much leaf removal to be safe for the plant. They also used the protective cages as props for their front feet to reach leaves and if three or four did this at the same time the wire buckled under their weight and allowed them access to most of the leaves on these new plants. Only rigid wire panels would have prevented this and would have resulted in increased expense. The project was ended by removing the lambs as too much damage was being done to the plants.

The feasibility of using lambs to graze between-row grasses and help control weeds in the grape row is not probable. If there were no young or replacement plants that need to be protected, and if the trunks on the plants are very sturdy, and if the canopy is well established to the trellis, then possibly this strategy would work.

The lambs did also graze on the grasses and weeds as intended. They were observed eating all of the weed types except thistle. For control of vegetation, they should have been placed in the case area a bit earlier in the season as plentiful moisture made the grass quite tall when they went in and thus they walked down a lot of it. Timing of introduction of the lambs would need to be earlier than mid-June to keep ahead of the first grass growth; however, our lamb producer uses spring lambing which means weaning in mid-June.

Weed and grass management in the control area continued as usual with mowing and weed spraying as needed. Mowing was adequate to control weeds from going to seed in the mid-row grassed strip. No chemical was used there, but occasional hand chopping of thistle was used to keep them from spreading—labor intensive. It was helpful to obtain data on the costs and labor to maintain vegetative control in the one quarter acre control area. The labor to control by spraying and mowing was not significant compared to the work that went into making the protective cages for the youngest plants. Timely and selective spraying by hand kept the cost down as well as saving on the use of extra chemical.

No educational event was planned due to the cancellation of the research component. No follow up soil tests were done. Type and number of weeds in the control area (as determined by counting weed incidence in a quadrant) did not vary in most rows from the beginning of the season to the end except directly around the grape trunks within the row where hand spraying of weeds was used as a method of control. In the row, spraying killed weeds shortly after they emerged but involved constant vigilance and time to do the spraying.

WORK PLAN
A workshop on IPM and calibrating small sprayers for yards/orchards/vineyards is still a possibility but budget cuts for Extension staff may affect the availability of an expert to lead the workshop.

OUTREACH
Information about the intent and subsequent cancellation of the research was sent to the local Extension educator, State Extension IPM Specialist, and SD grape listserv. No demonstration day was held due to not having a research project to report on. Visitors to the vineyard were told about the research project—lamb producer, neighbors, customers, Farm Service Agency staff.