February, 1999
1998 Hundley-Whaley Farm Weed Control Research
by Donald E. Null, Regional Agronomy Specialist
Telephone 660-564-3363
e-mail: nulld@missouri.edu
University Outreach and Extension
About the Site: The Hundley-Whaley Farm is located in
Northwest Missouri, near Albany in Gentry county. The topography
for the site could best be described as a second bottom of the East
Fork of Grand River. The soil type varies somewhat but it is
predominantly Grundy Silt
Loam.
Soil tests generally show high phosphorus and low potassium. The
soil pH ranges from
6.0 to 6.5 and the organic matter level ranges from 2.8-3.2%.
Fertility Program: Soybeans at the farm do not receive
applied fertilizer. The field corn research plots receive an
application of 180-0-90 applied to the soil surface right after
planting. The
nitrogen source is ammonium nitrate.
About the Research: The weed control research at the
farm is under the direction of Donald E. Null, Regional Agronomy
Specialist, University Outreach and Extension, Grant City, Missouri.
Null works cooperatively with Industry, Commodity Groups, University
of Missouri Scientists and the Hundley-Whaley Planning Committee to
conduct approximately fifty weed control studies
annually.
The research is all small plot work. Plot size ranges from 6'x30' to 12'x30'. When
possible on the 12'x30' plots, only one-half or 6' of the plot is treated to allow for running checks.
Experimental design is primarily Randomized Complete Block but some Split Block design is
used. Most treatments are replicated three times, however, experiments that call for yield data are
usually replicated from four to six times.
Weather for 1998: The weather at Hundley-Whaley for
1998 could be classified as wet, with moderate summer temperatures.
April was wet with little field work; May rainfall was moderate
enough to allow for good field work; June was excessively wet; July,
August and September provided good moisture for a developing and
maturing crop. Crop performance could generally be classified as
excellent. Corn produced 160-220 bu/acre. Soybeans produced 40-60
bu/acre unless there was a failure to obtain a stand due to the
unusually wet weather in June. Table 1 below shows a summary of
temperatures and rainfall for the primary growing
months of 1998. Temperatures are reported in degrees F.
Weather April May June July August
Average temperature
(max/min) 62.2/41.1 78.7/58.4 80.7/62.2 86.5/68.8 87.4/67
Days with measurable
rainfall 11 9 18 11 9
Total rainfall
in inches 4.15 3.07 6.78 3.35 2.90
Table 1
Crop Varieties: Nearly all of the Roundup Ready
soybeans in the test were Asgrow AG3701 or AG3601 which were
tolerant to both glyphosate and the sulfonylureas (i.e., RR-STS).
Row Widths: Soybeans were planted in either 10" or 36"
rows. A 6' wide Tye no-till drill was used to plant the 10" rows
and a John Deere 7100 planter was used to plant the 36" rows. All
corn was planted in 36" rows with the JD 7100 planter.
Additives: Unless otherwise specified, AMS (Ammonium
Sulfate) is applied with all Roundup
treatments at a rate equal to 17 pounds/100 gallons of spray solution.
Spraying Equipment: About one-half of the treatments
were made with a tractor-mounted spray boom and the other one-half
with CO2 backpack sprayer. In either case the nozzle spacings are
18" and the nozzle size is 0.2GPM. Spray Systems 11002 nozzles are
used. Spray pressure is generally 30 psi at the nozzle. Spray
solutions are mixed to provide 20 GPA.
Reporting the Data: This report will be made under three
main headings. They are as follows:
1. Roundup Ready soybean research and those studies that include Roundup
treatments to RR soybeans.
2. Conventional soybean weed control programs.
3. Corn weed control programs.
Disclaimer: The data reported here are for 1998 only.
Weather conditions can have a very big impact on weed and crop
species response to herbicide treatments. The weed control and crop
responses reported here should not be considered as something that
will occur on your own farm. Always be cautious of research data
limited to one year at one location.
These data are not to be construed as University recommendations.
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