Oakes
James
Loken et al., North Dakota State University
Weed control using herbicides
applied as micro-rates in onion.
|
Soil: |
Hecla sandy loam and Maddock sandy loam; pH=6.2; 1.5% organic matter;
soil-P was very high, soil-K was high and soil-S was medium. |
|
Previous crops: |
2006 – edible bean and sunflower; 2005 – sweetcorn; 2004 –
cabbage and soybean. |
|
Seedbed preparation: |
Disk
fall of 2006. Multiweed (field cultivate)
once on April 18 to smooth seed bed. |
|
Planting: |
Direct seeded onions (Teton @ 220,000 seeds/acre) on April 19
with a Monosem precision planter.
Planted onions with 2 lines per row, 2.5 inches between lines, with
the rows on 16-inch centers. |
|
Plots: |
Plots were 6 ft (four rows) wide by 17 ft long. The study had 4 reps. |
|
Fertilizer: |
November
2006, broadcast 9 lbs N/acre, 43 lbs P2O5/acre, 101 lbs
K2O/acre and 13 lbs S/acre as 11-52-0, 0-0-60 and 90% elemental
Sulfur. Sidedressed 30 lbs N/acre as
32-0-0 on June 5, June 20, June
28 and July 13. |
|
Irrigation: |
Subsurface drip irrigation as needed. |
|
Pest control: |
Select
(8 oz/acre) + COC (1.0% v/v) on June 4; Buctril (1 pt/acre)+
Goal 2EC; (0.5 pt/acre) on June 20.
Outlook (21 oz/acre) on July 3, Buctril (1 pt/acre)+ Goal 2EC;
(0.6 pt/acre) on July 11, Goal (8 oz/acre) and Fusilade (12 oz/acre) + NIS
(0.5% v/v) on July 25. Quadris (8
oz/acre) on July 25 and Quadris (12 oz/acre) on August 8 and August 24,
Pyraclostrobin (12 oz/acre) on August
3 and August 16 for disease control. Lorsban (4 qt/acre) on May 16 for root
maggots. |
|
Harvest: |
September 4, 2007 |
Go to top of onion weed control study
Weed
control using herbicides applied as micro-rates in onion, Oakes.
Loken,
James R., Harlene Hatterman-Valenti, Collin Auwarter, and Walt Albus.
An experiment was conducted at the
Oakes Irrigation Research Site near Oakes, ND, to compare early-season weed
control of bromoxynil,
oxyflourfen
(water based formulation), metribuzin, and aciflourfen applied at micro-rates
to a standard pre-emergence treatment of DCPA in onion
(Allium cepa L.). The standard pre-emergence treatment of DCPA
was applied one week after planting (April 24). At time of weed cotyledon stage
(May
9) herbicides were applied as micro-rates at 1/16, 1/8, and 1/4 of their lowest
labeled rates every 7 days, with 2 or 3 total applications.
Herbicide
micro-rates were applied with a CO2 pressurized backpack
sprayer. A standard application of
bromoxynil, oxyfluorfen, and dimethenamid-P
was
applied on June 20 (3-leaf stage) to control broadleaf weeds. Another standard application of bromoxynil
and oxyfluorfen was made on July 11
(5-6-leaf
stage) as a final late-season broadleaf weed control measure. Treatments were
evaluated for overall control of redroot pigweed
(Amaranthus retroflexus L.) and common
lambsquarters (Chenopodium album L.)
seven days after each micro-rate treatment using weed counts
and
approximately two weeks after the first standard application using a visual
evaluation. On September 4, 10 ft of
the middle two rows of each
plot
were harvested for grade and yield analysis.
After harvest, onions were allowed to cure and then were graded. Split and diseased bulbs
were
graded as culls regardless of diameter.
Samples were taken to check for % double-centered bulbs.
Herbicide application dates, timings, and
environmental conditions for Oakes, 2007.
Application Date: 4-24 5-9 5-16 5-23 6-20 7-11
Onion Stage: PRE PRE E 1-1½ lf 3 lf 5-6 lf
Air Temp., (F): 54 72 52 59 74 66
Wind Velocity, (MPH): 5 5 5 7 6 6
Soil Temp., (F): 53 65 63 66 78 79
Operating Pressure: 40 psi 40 psi 40 psi 40
psi 40 psi 40 psi
Nozzle Type: Flat
Fan Flat Fan Flat Fan Flat Fan Flat Fan Flat
Fan
Nozzle Size: 8002 8002 8002 8002 8002 8002
Spray Volume, GPA: 20 20 20 20 20 20
Results: Micro-rate herbicide applications of
oxyfluorfen and bromoxynil caused slight injury to onion during establishment.
This was due to cooler
temperatures at application time. Onion maggots
severely reduced yields. Plants counts
reinforced visual weed control ratings. Visual ratings indicated
that excellent common lambsquarters and redroot
pigweed control occurred early on with 3 applications of bromoxynil at 0.063 lb
ai/A and 3 applications
of oxyfluorfen at 0.013 lb ai/A. The greatest
total onion yields were also associated with the oxyfluorfen treatment. Early-season broadleaf weed control
was necessary to achieve high yields with the
micro-rate treatments.
Go to top of onion weed control study
Table 1. Effect of
herbicide, rate, and number of applications on weed control, onion yield, and
grade at Oakes
|
|
Micro-rate |
# of |
Population
colq |
4Population
rrpw |
5% Weed
Control colq |
% Weed
Control rrpw |
3Yield
(lbs/A) |
||||
|
Herbicide |
(lb
ai/A) |
App. |
11WAT1 |
2WAT3 |
1WAT1 |
2WAT3 |
29WAP |
9WAP |
2.25-3” |
3” or
> |
Total |
|
Bromoxynil |
0.0156 |
2 |
2.75 |
2.5 |
0.75 |
1 |
25 |
50 |
827 |
179 |
2900 |
|
Bromoxynil |
0.0313 |
2 |
0 |
0 |
1.75 |
0.5 |
71 |
74 |
2122 |
468 |
6173 |
|
Bromoxynil |
0.0625 |
2 |
0.25 |
0 |
1.5 |
0.25 |
96 |
90 |
5036 |
1438 |
9986 |
|
Bromoxynil |
0.0156 |
3 |
5.5 |
2.5 |
0.5 |
0.75 |
73 |
93 |
1151 |
755 |
5878 |
|
Bromoxynil |
0.0313 |
3 |
1 |
0.25 |
2.25 |
0 |
93 |
88 |
1691 |
935 |
5453 |
|
Bromoxynil |
0.0625 |
3 |
0 |
0.25 |
0 |
0 |
100 |
94 |
4029 |
575 |
8497 |
|
Oxyfluorfen |
0.0031 |
2 |
6.75 |
7.75 |
2 |
2.5 |
19 |
50 |
611 |
0 |
3266 |
|
Oxyfluorfen |
0.0063 |
2 |
0.25 |
0.75 |
.25 |
0 |
53 |
76 |
3849 |
935 |
8554 |
|
Oxyfluorfen |
0.0125 |
2 |
0.75 |
0.25 |
1.5 |
0.25 |
79 |
100 |
6007 |
1942 |
12447 |
|
Oxyfluorfen |
0.0031 |
3 |
4.5 |
2.5 |
2 |
1.25 |
38 |
73 |
5288 |
1546 |
9878 |
|
Oxyfluorfen |
0.0063 |
3 |
1 |
1.5 |
0.5 |
0.25 |
50 |
91 |
4676 |
1978 |
10108 |
|
Oxyfluorfen |
0.0125 |
3 |
2 |
1 |
0.25 |
0 |
63 |
96 |
7014 |
1978 |
13785 |
|
Metribuzin |
0.0047 |
2 |
7 |
6.5 |
3 |
2 |
70 |
31 |
252 |
0 |
2532 |
|
Metribuzin |
0.0094 |
2 |
7.5 |
2.25 |
2.25 |
2 |
38 |
44 |
0 |
0 |
1036 |
|
Metribuzin |
0.0188 |
2 |
1.75 |
1.5 |
1.75 |
3 |
56 |
70 |
863 |
0 |
3561 |
|
Metribuzin |
0.0047 |
3 |
2.25 |
2 |
3.75 |
2 |
35 |
48 |
252 |
144 |
1841 |
|
Metribuzin |
0.0094 |
3 |
1 |
0.75 |
1.75 |
0.5 |
69 |
86 |
179 |
0 |
2654 |
|
Metribuzin |
0.0188 |
3 |
1 |
0.25 |
2 |
0.25 |
78 |
88 |
575 |
0 |
1999 |
|
Acifluorfen |
0.0156 |
2 |
2.25 |
2.75 |
2 |
1.5 |
31 |
41 |
144 |
0 |
2417 |
|
Acifluorfen |
0.0313 |
2 |
7.25 |
7.75 |
0.75 |
1.5 |
24 |
21 |
1330 |
0 |
3288 |
|
Acifluorfen |
0.0625 |
2 |
3.25 |
3.25 |
0.5 |
0.5 |
14 |
86 |
611 |
0 |
2532 |
|
Acifluorfen |
0.0156 |
3 |
4.5 |
4.25 |
1.25 |
2 |
19 |
66 |
144 |
0 |
1172 |
|
Acifluorfen |
0.0313 |
3 |
5 |
5 |
1.75 |
0.5 |
18 |
90 |
683 |
0 |
3863 |
|
Acifluorfen |
0.0625 |
3 |
3.5 |
1.25 |
0 |
0 |
43 |
96 |
2734 |
1115 |
7389 |
|
Conventional Method Check |
1.5 |
1 |
1.25 |
0.75 |
53 |
31 |
1079 |
144 |
4475 |
||
|
DCPA - PRE |
7.5 |
— |
|
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|
|
|
|
|
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|
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Bromoxynil - 5 lf |
0.25 |
— |
|
|
|
|
|
|
|
|
|
|
Oxyfluorfen - 5 lf |
0.1 |
— |
|
|
|
|
|
|
|
|
|
|
Hand-Weeded Check |
— |
0 |
0 |
0 |
0 |
100 |
100 |
6691 |
3093 |
16181 |
|
|
LSD
(0.05) |
|
|
ns |
1.5 |
ns |
1.8 |
32 |
22 |
3446 |
1927 |
5680 |
11WAT1
denotes one week after first treatment.
29WAP
denotes nine weeks after planting.
3Cull yield
not shown.
4Average
populations taken from a 1 ft2 area.
5colq and rrpw
denote common lambsquarters and redroot pigweed respectively.
6ns denotes
not significant.
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