Ohio State University Research/Extension Bulletin

Agronomic Crops Team On-Farm Research Projects 1997

Special Circular 160-98


SOYBEANS

1997 Reduced Rates of Herbicides in Normal Soybeans

Objective

Determine if reduced rates of herbicides can provide adequate weed control and show no yield loss in no-tillage soybean utilizing pre-emergence and post-emergence herbicide applications.

Cooperator: Tim Warner
County of Site: Darke
Nearest Town: Greenville
Major Soil Type: Brookston Silty Clay Loam
Drainage (List Type): N/A
Irrigation: No
Tillage: None
Previous Crop: Corn
Soil Test: pH N/A
P N/A
K N/A
Fertilizer Applied: N/A
Herbicide Program: Listed in table
Plant Population: 210,000 seeds per acre
Plant Population @Harvest: N/A
Variety: Becks 299
Planting Date: April 29, 1997
Harvest Date: September 24, 1997

Materials and Methods

The plot size for this study was 20 feet wide and 300 feet in length. Each treatment was replicated three times. 2,4-D ester at 1.0 pt/A plus Prime Oil (COC) was added to treatments 1-7 and applied alone to treatment 8 to control existing weeds seven days prior to planting. The 1X Canopy rate was 6.0 oz/A and 1X Squadron rate was 3.0 pt/A. The post-emergence application of Basagran + Poast HC + Prime Oil + 28% Nitrogen at the 1X rate was 2.0 pt/A + 10.0 floz/A + 0.5%v/v + 2.0%v/v and applied as listed in the table.

Results

Treatment
and Rate1
Treatment Timing1 Weed Control
on July 24, 19971
Soybean
Yield1
(bu/A)
Treatment
Cost2
($/A)
Height
(inch)
DAP An. Gr.
( %)
1. Canopy (EPP) 1/2X- 7866212.06
2. Canopy (EPP) 1/2X-7
(POST) 1/4X1.2552936122.09
3. Canopy (EPP) 1/2X-7
(POST) 1/2X3.056986129.32
4. Squadron (EPP) 1/2X-7836217.00
5. Squadron (EPP) 1/2X-7
(POST) 1/4X1.2552956127.03
6. Squadron (EPP) 1/2X-7
(POST) 1/2X3.056986334.26
7. Squadron (EPP) 1X-7836129.16
8. Roundup (POST) 1X8.065956337.56
LSD (0.05%)7NS
1 Abbreviations: Height = annual grass height, DAP = days after planting,
An. Gr. = annual grass (giant foxtail and barnyardgrass), bu/A = bushels per acre,
EPP = early pre-plant application, POST = post-emergence application, LSD = least
significant difference, NS = no significant difference.
2 Treatment cost = cost of all herbicides and additives (including burndown)
and application cost at $2.00/A/application.

Summary and Notes

The annual grass pressure was light to moderate and the annual broadleaf pressure was non-existent. Canada thistle was present, which is why Basagran was used, but the thistle population was not uniform enough to rate. Treatments 1, 4, and 7 provided less than 87% control of annual grass, but yield was not significantly reduced.

For additional information, contact:

Jeff Stachler and Dr. Mark Loux
Kottman Hall
The Ohio State University
2021 Coffey Road
Columbus, OH 43210
614-292-1393 or 614-292-9081
stachler.1@osu.edu or loux.1@osu.edu


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