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Weed control in no-till
chickpea (2003)
B-90 chickpeas were seeded
April 28 into 7.5-inch rows at 180 lb/A. Individual plots were 10 x 30 ft and
replicated three times. PRE and POST treatments were applied April 30 and June
2, respectively. The primary weeds evaluated were kochia (Kocz), redroot
pigweed (Rrpw), and biennial wormwood (Biww). Chickpeas were harvested Aug 25.
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|
|
|
Kocz |
Rrpw |
Biww |
Chickpea |
|
Treatment |
Rate |
Timing |
Jun 7 |
Jun 20 |
Jun 7 |
Jun 20 |
Jun 7 |
Jun 20 |
Yield |
Test Wt |
|
|
|
|
% control |
lb/A |
lb/bu |
|
Roundup + Spartan/
Select |
13 fl oz + 2.67 oz/
5 fl oz |
PRE/
POST |
79 |
84 |
88 |
85 |
77 |
78 |
2309 |
61.0 |
|
Roundup + Spartan/
Select |
13 fl oz + 4 oz/
5 fl oz |
PRE/
POST |
94 |
96 |
95 |
96 |
92 |
81 |
2440 |
63.4 |
|
Roundup + Spartan/
Select |
13 fl oz + 5.33 oz/
5 fl oz |
PRE/
POST |
100 |
97 |
100 |
98 |
99 |
96 |
2669 |
63.3 |
|
Roundup + Spartan + Balance/
Select |
13 fl oz + 4 oz +
2 oz/
5 fl oz |
PRE/
POST |
100 |
100 |
100 |
99 |
100 |
100 |
2722 |
62.2 |
|
Roundup + Spartan +
Sencor/
Select |
13 fl oz + 4 oz +
0.33 lb/
5 fl oz |
PRE/
POST |
97 |
98 |
100 |
98 |
100 |
98 |
2633 |
62.7 |
|
Roundup + Spartan/
Tough + Select |
13 fl oz + 4 oz/
1.5 pt + 5 fl
oz |
PRE/
POST |
100 |
100 |
100 |
100 |
100 |
100 |
2696 |
62.5 |
|
Roundup + Spartan/
Sencor + Select |
13 fl oz + 4 oz/
0.25 lb + 5 fl
oz |
PRE/
POST |
95 |
100 |
98 |
100 |
100 |
100 |
2438 |
62.7 |
|
Handweeded checkb |
|
|
100 |
100 |
100 |
100 |
100 |
100 |
2638 |
62.2 |
|
Untreated |
|
|
0 |
0 |
0 |
0 |
0 |
0 |
-- |
-- |
|
LSD (0.05) |
|
|
6 |
5 |
7 |
4 |
4 |
3 |
NS |
NS |
|
CV |
|
|
4 |
3 |
5 |
2 |
3 |
2 |
8 |
1.8 |
aRoundup
treatements were Roundup UltraMax applied with AMS at 2.5 gal/100 gal, Select
was applied with COC at 1% v/v.
bRoundup
+ Spartan followed by Tough + Select were applied to aid in handweeding.
Several PRE and POST
herbicide treatments were evaluated for chickpea tolerance and weed control.
Herbicide treatments included Spartan alone, Spartan tank mixed with Balance or
Sencor, or Spartan followed postemergence by Tough or Sencor. All PRE
treatments were tank mixed with Roundup UltraMax. Previous studies have shown
Sencor applied postemergence to cause slight to moderate crop injury. Sencor
applied postemergence is not a labeled treatment.
In late May, the chickpea
crop started to exhibit symptoms consistent with clopyralid injury.
Unfortunately, we failed to remember that Curtail (clopyralid + 2,4-D) was
applied to this field in 2002. Chickpea tolerance to herbicides in this study
was not evaluated due to the confounding effect of the herbicide carryover from
2002. Chickpea injury due to Curtail carryover was not as severe in this
no-till study compared to the conventionally-tilled chickpea study.
All treatments provided
excellent (>90%) kochia and redroot pigweed control, with the exception of the
low Spartan rate (2.67 oz), which provided good control (80-89%) of kochia and
pigweed. All treatments provided excellent biennial wormwood control with the
exception of the two lower Spartan rates (2.67 and 4 oz). Statistically, there
was no significant yield difference between herbicide treatments. The untreated
check could not be harvested because it was completely overrun by kochia.
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