Steve Ruhl, Extension Agriculture and Natural Resources Agent
Tom Weiler, Morrow County Producer
Ed Lentz, Extension Agronomy Specialist
The adoption of Roundup Ready soybeans has been rapid. However, there are a few weeds that Roundup Ultra doesn't control satisfactorily and it has no residual effect. As a result, producers may want to use other herbicides with Roundup Ultra. This trial was conducted to examine the effect of applying other herbicides with Roundup Ultra on the yield of Roundup Ready soybeans.
| Nearest Town: | Chesterville | Soil Test: | pH 7.0 |
| Major Soil Type: | Chili | P 23 ppm | |
| Drainage: | Systematic | K 154 ppm | |
| Previous Crop: | Corn | Fertilizer Applied: | 200 lbs of 0-0-60 per acre |
| Tillage: | Fall chisel & field cultivation | Plant Population: | 200,000 seeds/acre |
| Variety: | Callahan 7391RR | Harvest Plant | |
| Planting Date: | May 12 | Population: | 168,000 plants/acre |
| Harvest Date: | October 1 | ||
The field chosen has tremendous giant ragweed, lambsquarter, and giant foxtail pressure. The field was chisel plowed and weeds worked out at planting time. The additional herbicides used were Cobra (5 oz./A), Canopy XL (3 oz./A), and Pursuit (1.44 oz./A). Canopy XL was applied preemergence. Pursuit and Cobra were applied post-emergent within an hour after an application of 1.5 quarts of Roundup Ultra and 3 pounds of AMS per acre at the V-3 stage of soybean growth. These treatments were compared to 1.5 quarts of Roundup Ultra sprayed alone at the V-3 stage.
Giant ragweed pressure was severe with 24- to 36-inch tall weeds at the time of the postemergence application. The treatments were replicated three times with individual treatment plots being 20 feet x 500 feet.
| Herbicide Treatment | Soybean Yield (bu/acre) | Total Herbicide Cost ($) |
|---|---|---|
| Cobra + Roundup + 3# AMS/A | 62.99 | 27.33 |
| Canopy XL fb Roundup + 3# AMS/A | 61.60 | 30.71 |
| Roundup + 3# AMS/A (V3 Stage) | 60.06 | 21.75 |
| Pursuit + Roundup + 3# AMS/A | 58.99 | 46.33 |
F = 0.83 No significant differences among treatment means at P = 0.05 CV = 11.0% | ||
Weed control was excellent for all treatments. According to the results of this trial, the addition of the other herbicides used did not significantly effect yields of the Roundup Ready soybeans.
For additional information, contact:
Steve Ruhl
Ohio State University Extension, Morrow County
871 W. Marion Rd., Suite 102
Mt. Gilead, OH 43338
419-947-1070
ruhl.1@osu.edu