ArticlePDF Available

Abstract

Successful screening of suitable onion (Allium cepa L.) varieties, viable production areas, and potential marketing options suggest that onions are a potential alternative crop for Oklahoma and northeast Texas. Unfortunately, onion's slow growth rate, short height, non-branching plant structure, low leaf area, and shallow root system can result in a total loss of marketable yields as a result of weed competition. Field research was conducted in 2002 and 2003 in southeast Oklahoma (Lane, OK) to determine the weed control efficacy of selected preemergent synthetic herbicides and corn gluten meal (CGM) for use in spring-transplanted onion cv. Hybrid Yellow Granex PRR, production. There were 21 treatments [12 synthetic herbicide treatments, 5 CGM application rates, a full-season weed-free (hand-weeded) treatment, a full-season weedy-check, a partial-season weed-free (weed-free for the first half of the growing season), and a weedy-check without onions]. Weed cover and weed control ratings were collected at 46 days after planting (DAP) and at harvest. The synthetic herbicide treatments resulted in significantly greater weed control at 46 DAP and harvest compared to all CGM application rates. The highest CGM rate (4,000 kg·ha) did maintain fair, 72.1%, total weed control and good, 82.7%, broadleaf weed control until 46 DAP. Among the synthetic herbicides, pendimethalin provided the best early and full season weed control.
Corn Gluten Meal
as an Alternative Weed Control Option
for Spring-Transplanted Onions
Charles L. Webber III
James W. Shrefler
Merritt J. Taylor
ABSTRACT. Successful screening of suitable onion
(Allium cepa
L.)
varieties, viable production areas, and potential marketing options sug-
gest that onions are a potential alternative crop for Oklahoma and north-
east Texas. Unfortunately, onion's slow growth rate, short height,
non-branching plant structure, low leaf area, and shallow root system
can result in a total loss of marketable yields as a result of weed competi-
tion. Field research was conducted in 2002 and 2003 in southeast
Oklahoma (Lane, OK) to determine the weed control efficacy of Se-
Charles L. Webber III (E-mail; cwebber-usda@lane-ag.org
) is affiliated with the
United States Department of Agriculture, Agricultural Research Service, South Cen-
tral Agricultural Research Laboratory, P.O. Box 159, Lane, OK 74555.
James W. Shrefler (E-mail: jshreflerokstate@lane-ag.Org)
is affiliated with the
Department of Horticulture and Landscape Architecture and Merritt J. Taylor (E-mail:
mtaylor-okstate@
lane- ag.org
) is affiliated with Department of Agricultural Econom-
ics, Oklahoma State University, P.O. Box 128, Lane, OK
74555.
Address correspondence to: Charles L. Webber HI at the above address.
The authors thank Buddy L. Faulkenberry HI for maintaining the field experiments
and data collection. Mention of a trademark, vendor, or proprietary product does not
constitute a guarantee or warranty of the product by the USDA and does not imply its
appro'al to the exclusion of other products that may also be suitable.
The article was prepared by a USDA employee as part of his official duties. Copy-
right protection under US copyright law is not available for such works, and there is no
copyright to transfer. The fact that the private publication in which the article appears is
itself copyrighted does not affect the material that is a work product of the US Govern-
ment, which can be freely reproduced by the public.
International Journal of Vegetable Science, Vol. 13(3) 2007
Available online at http://ijvs.haworthpress.com
© 2007 by The Haworth Press. All rights reserved.
doi:10.l300/J5l2vl3fl03_03
17
18
INTERNATIONAL JOURNAL OF VEGETABLE SCIENCE
lected preemergent synthetic herbicides and corn gluten meal (CGM) for
use in spring-transplanted onion cv. Hybrid Yellow Granex PRR, pro-
duction. There were 21 treatments 112 synthetic herbicide treatments,
5
CGM application rates, a full-season weed-free (hand-weeded) treat-
ment, a full-season weedy-check, a partial-season weed-free (weed-free
for the first half of the growing season), and a weedy-check without on-
ions]. Weed cover and weed control ratings were collected at 46 days af
-
ter planting (DAP) and at harvest; The synthetic herbicide treatments
resulted in significantly greater weed control at 46 DAP and harvest
compared to all CGM application rates. The highest CGM rate (4,000
kg-ha
-1
) did maintain fair, 72.1%, total weed control and good,
82.7%, broadleaf weed control until 46 DAP. Among the synthetic her-
bicides, pendimethalin provided the best early and full season weed
control.
doi:lO.1300/J512v13n03
03
[Article copies available for afeefroin
The Haworth Document Delivery Service: 1-800-HA WORTH. E-mail address:
<docdeliveiy@haworthpress. coin> %Vebsire: <http://www.Haworth
Press corn>
© 2007
by The Haworth Press. All rights reserved. /
KEYWORDS.
A Ilium cepa,
corn gluten meal, onion, oxyfluorfen,
pendimethalin, weed competition
INTRODUCTION
Oklahoma producers are interested in sweet onion
(A
ilium cepa L.)
as an alternative crop for farm diversification (McCraw, 1990; Shrefler,
2004). Screening for suitable onion cultivars for Oklahoma production
continues for both fall direct-seeded (McCraw, 1990; Shrefler, 2001,
2004) and spring transplanted onions (Shrefler, 2002, 2004). Further re-
search has demonstrated the feasibility of producing onion transplants
for spring production by fall direct-seeding in hoop-houses (Shrefler et
al., 2004). However, the lack of weed control can result in the total loss
of marketable onions (Wicks et al., 1973). Onions do not compete well
with weeds due to their slow growth rate (Wicks et al., 1973; Umeda et
al., 1998; Bell and Boutwell, 2001), short height (Singh et al., 1992),
non-branching plant structure (Singh et al., 1992), low leaf area (Dunan
et al., 1996; Bell and Boutwell, 2001), and shallow root system (Singh
et al., 1992).
Although mechanical weed control through cultivation is useful for
controlling weeds between rows, it is ineffective for controlling weeds
between plants within rows. Chemical weed control is an alternative to
Webber, Shrefler, and Taylor
19
hoeing or hand removal of weeds from within the crop row. Potential
chemical weed control options include conventional synthetic herbi-
cides such as pendimethalin
[N-(
l-ethyl propyl)-3,4-dimethYl-2,6dini
trobenzenamine] and oxyfluorfen [2-chloro- I -(3-ethoxy-4-nitrophen-
oxy)-4-(trifluoromethyl)benZefle], but also include alternative organic
herbicides such as corn gluten meal (CGM). Pendimethalin is a
dinitroaniline herbicide (Ahrens, 1994) used as a preemergence or early
postemergence herbicide registered for use in many crops including
transplanted dry onion bulbs at rates of 0.55-1.66 kg-ha
-
' ai) [Prowl 3.3
EC, American Cyanamid Co., Wayne,
NJ
)],
and
0.56-1.68
kg-ha-
1
ai
(Sharp, 2002) for control of annual grass and broadleaf weeds (Ahrens,
1994). Oxyfluorfen is a diphenyleth
,
er herbicide used as a preemergence
or over-the-top postemergence herbicide for control of small-seeded
broadleaf weeds and suppression of annual grass weeds in many crops
(Ahrens, 1994), including transplanted onions (0.56 kg aiha' maxi-
mum per season) [Goal 2XL, Dow AgroSciences LLC, Indianapolis,
IN)] and 0.13 - 0.28 kg-ha-
1
ai (Sharp, 2002). Research by Westra et al.
\(1990) using 0.34 kg-ha
-1
ai oxyfluorfen and Singh etal. (1992) using
\pendimethalin at 1.0 and 1.5 kg-ha-
1
ai, oxyfluorfen at 0.10 and 0.15
kg-ha-
1
ai, and tank mixes of pendimethalin with either 0.75 or 1.0
kgha' ai with oxyfuorfen 0.1 kg-ha-
1
ai did not result in injury to on-
ion transplants.
When a crop such as onion lacks a competitive advantage, it often re-
quires an increase in the amount, duration, and diversity of herbicides
needed to control the weeds, resulting in a greater environmental con-
cern (Dunan et al., 1996). Weed control systems usually benefit from
inclusion of alternative weed control methods rather than sole reliance
on conventional synthetic herbicides. Alternative weed control methods
include crop rotations, cover crops, planting systems, mechanical meth-
ods, and organic herbicides. In addition, a combination of several weed
species usually infest a given production area or field. It is also impor-
tant to develop integrated weed control systems to address a wide range
of weed control and production scenarios.
CGM is a certified organic material for organic crop production.
Christians (1993) was the first to determine that soil-incorporated corn
meal was phytotoxic, reducing creeping bentgrass
(Agrostis palustris
Huds.) establishment. It was also determined that it was the CGM frac-
tion that produced the greatest inhibitory effect and reduced root forma-
tion in several weed species, including creeping bentgrass
(Agrostis
palustris Huds.) and crabgrass
(Digitaria
spp.). CGM is the by-product
of the wet-milling process of corn (Quarles, 1999; Bingaman and Chris-
20
INTERNATIONAL JOURNAL OF VEGETABLE SCIENCE
tians, 1995). The powder (McDade, 1999) has been used as a compo-
nent in dog, fish, and livestock feed (Quarles, 1999; Christians 1991,
1995).
In greenhouse studies, Bingaman and Christians (1995) determined
that CGM applied at 3,240 kg-ha-
1
reduced plant survival, shoot length,
and root development for 22 weed species tested, whether the CGM was
applied to the soil surface as a preemergence herbicide or mixed into the
top 2.54 cm as a preplant-incorporated herbicide. Although plant devel-
opment was reduced for all weeds tested, the extent of susceptibility dif-
fered across species. Plant survival and root development was reduced
by at least 70% and shoot length by at least
50%
for black nightshade
(Solanurn nigrurn L.),
common lambsquarters
(Chenopendium album
L.),
creeping bentgrass, curly dock
(Rumex crispus L.),
purslane
(Por-
tulaca oleracea L.),
and redroot pigweed
(Amaranthus retroflexus L.).
When CGM was applied as a preplant incorporated herbicide, the fol-
lowing weeds had at least a
50%
reduction in plant survival and shoot
length and at least an 80% reduction in root development: catchweed
bedstraw
(Galium aparine L.),
dandelion
(Taraxacum officinale
Weber),
giant foxtail
(Setariafaberi
Herrm.), and smooth crabgrass
[Digitaria
ischaemum
(Schreb.) Schreb. ex Muhl]. Plant survival was less than
31 %for barnyardgrass
[Echinochloa crus-galli (L.)
Beauv.] and vel-
vetleaf
(Abutilon theophrasti
Medic.). Field research was conducted in
southeast Oklahoma (Lane, OK) to determine the weed control efficacy
of selected preemergent synthetic herbicides and CGM for use in
spring-transplanted onion production.
MATERIALS AND METHODS
There were 21 weed control treatments with 4 replications applied to
spring-transplanted onions in 2002 and 2003. Certified onion seeds
(cv. Hybrid Yellow Granex PRR) were planted into Speedling (r)
(Speedling, Inc., Sun City, FL) trays on II Dec. 2001 and 2002 and
grown in the greenhouse until just prior to transplanting, when they
were hardened off outside and prepared for transplanting to the field.
Prior to transplanting, the Bernow fine-loamy, siliceous, thermic
Glossic Paleudalf soil was plowed to incorporate the winter wheat cover
crop. Fertilizer was applied according to recommendations (Motes and
Roberts, 1994) and incorporated prior to preparing raised beds (1.4 m
wide). The beds were on 1.8 m centers and oriented east to west with a
1.5-m alley between the 3.0-rn long plots.
Webber, Shrefler, and Taylor
21
On 14 March 2002 and 26 March 2003, onion seedlings were trans-
planted in two rows on the raised beds with 91 cm between rows. In 2002,
onion transplants were thinned in all plots to uniform stands of I plant/
15.2 cm within rows (20 plants/3m) with a total of 40 plants per 3-rn plot
(71,758 plantsha'). In 2003, due to transplanting conditions, the onions
were transplanted and thinnedto a uniform I plant/20.3 cm (15 plants/
3m) with a total of 30 plants per 3-rn plot (53,818 plantsha').
Herbicide applications included synthetic [Prowl 3.3 EC (pendi-
methalin), American Cyanamid Company, and Goal 2XL (oxyfluorfen)
Dow AgroSciences LLC] and organic (CGM) herbicides. Although
there are other preemergence herbicides registered for use for trans-
planted onions, these herbicides provide consistently high weed control
and crop safety in our production area. The 21 weed control treatments
included 12 synthetic herbicide treatments,
5
CGM application rates, a
full-season weed-free (WF) (hand-weeded) treatment, a full-season
weedy-check, a partial-season weed-free (weed-free for the first half of
the growing season, 46 days after planting (DAP)), and a weedy-check
\without onions. A weedy-check without onions was included to isolate
the competitive impacts of the onions and the weed control treatments.
Within 24 hrs of transplanting, the synthetic herbicides (pendimethalin
and oxyfluorfen) were applied at 187 Lha', 276 kPa, with a CO2
backpack sprayer equipped with XR8002VS (Spraying Systems Co.,
Wheaton, IL) nozzles on 51-cm spacing. Synthetic herbicides were ap-
plied at three rates. The herbicide treatments included pendimethalin
applications at 0.5 kg-ha-
1
ai (ai = active ingredients of the herbicide
applied), 1.0 kg-ha
-
' ai and 1.5 kg-ha
-
ai, oxyfluorfen at 0. 1, 0.2, and
0.3 kg-ha-
1
ai, and tank-mixed at these three levels. In addition, the
highest rate of each herbicide treatment, pendirnethalin at
1.5
kg -ha-
ai, oxyfluotfen at 0.3 kg-ha-
1
ai, and the tank mix of pendimethalin at
1.5
kg-ha-
1
ai with oxyfluorfen at 0.3 kgha' ai were applied and kept
weed-free by hand-weeding.
CGM was applied by hand to the soil surface and not- incorporated,
spreading the dry powdered material (Alliance Milling Company,
Denton, Texas) at 4 rates (1,000, 2,000, 3,000, and 4,000 kg-ha-
1
) to
determine weed control efficacy. A weed-free (hand-weeded) treatment
was also combined with the highest CGM rate (4,000 kg-ha
-1
). The
other weed control treatments included a full-season weedy-check
(weeds allowed to grow), a full-season WF hand-weeded treatment, a
partial-season weed-free (weed-free for the first half of the season), and
an onion-free weedy-check (no onions and no weed control). The on-
22
INTERNATIONAL JOURNAL OF VEGETABLE SCIENCE
ion-free treatment was included to determine the effect of onion
competition on weed growth.
Weed cover and weed control ratings were made at midseason 46
DAP and at harvest for total, broadleaf, and grass weeds. The weed
cover ratings represent the percentage weed cover within a treatment
plot area that is covered by weeds where 0 is no weed cover and 100 is
100% of the plot area is covered by weeds. The weed control ratings
represent the percentage weed control for an experimental treatment
compared to the weedy-check with 0 for no weed control and 100 for
complete control. Weed cover and weed control ratings were used
rather than weed counts and biomass collections as a result of the large
number of plots, 84 plots per year, and the destructive nature of the bio-
mass samples. The onions were harvested on 17 June 2002
(95
DAP)
and 17 June 2003 (83 DAP). Onion yields resulting from the weed con-
trol treatments will be discussed in detail in a manuscript devoted to that
subject.
Rainfall during the growing season, from transplanting to harvest, for
2002 was
53.8
cm (16.3 cm during the first week alone) compared to
19.8 cmfor 2003. In 2003, an additional 6.4 cm of supplemental water
was added through sprinkler irrigation to provide a seasonal total of
26.2 cm. The 30 year average rainfall for the location from 15 March to
15 June is 36.0 cm.
The experiment was RCBD with four replications and conducted in
2002 and 2003. All data were subjected to ANOVA and mean separa-
tion using LSD with P = 0.05 (SAS Inc., SAS, Cary, NC). The percent-
age weed cover and weed rating data were prepared for analyses using a
square root arcsine transformation to normalize the data. Mean differ-
ences were determined using the transformed data and the non-trans-
formed data values are reported using the mean differences determined
with the transformed data.
RESULTS AND DISCUSSION
Crop injury.
No injury was observed on the onion leaves or the visual
portion of the bulbs as a result of any of the weed control treatments for
either year (data not shown). These results are consistent with research
with onion transplants by Westra et al. (1990) using a higher rate of
oxyfluorfen (0.34 kg-ha' ai) and Singh et al. (1992) using pendi-
methalin at 1.0 and
1.5
kg-ha- ' ai, oxyfluorfen at 0.10 and 0.15 kg-ha-
1
Webber, Shrefler, and Taylor
23
ai, and tank mixes of pendimethalin with either 0.75 or 1.0 kg-ha
-
' ai
with oxyfuorfen 0.1 kg-ha
-
' ai.
Others have reported herbicide injury to onions with applications of
CGM (McDade and Christians, 2000), pendimethalin (Umeda et al,
1998), and oxyfluorfen (Sieczka et al., 1982), although in these cases
phytotoxicity was present on direct-seeded onions rather than trans-
plants. Research has shown that pendimethalin and oxyfluorfen can be
safely applied to direct-seeded onions (Cudney and Orloff, 1988; Umeda
et al., 1998), but greater care is required with the application rates, ap-
plication timing, and the irrigation methods when pendimethalin is used
for direct-seeded onions (Umeda et al.; 1998).
Mid-season weed cover (46 DAP).
There were no significant year-
y-treatment interactions for the weed ratings at 46 DAP (Table 1), and
the weed cover and weed control data for 46 DAP is averaged across
treatments (Table 2) and years (Table 3). There were no significant dif-
ferences between years at 46 DAP for any of the weed cover and weed
control data (Table 2).
Total, broadleaf and grass weed cover remained low, less than 29%,
for all weed control treatments at 46 DAP (Table 3). The weedy-check
treatments, with and without onions, had the highest weed presence for
total, broadleaf, and grass weeds, 28.8%,
22.5,
and 6.3%, respectively
(Table 3). The lack of differences between weeds in onion-free weedy-
check and weedy-check onion treatment is an indication of the low
competitive impact of onions on weeds as reported elsewhere (Wicks et
al., 1973; Singh et al., 1992; Dunan et al., 1996; Umeda et al.
-
,'I 998; Bell
and Boutwell, 2001). At 46 DAP the weedy-check had 78% broadleaf
and 22% grass weeds (Table 3). The primary broadleaf weeds within
the weedy-check included spiny amaranth
(Amaranthus spinosus L.),
50-60%,
and tumble pigweed
(Amaranthus albus L.),
10-20%, cutleaf
groundcherry
(Physalis angulata L.),
15-20%, and less than I % of
Pennsylvania smartweed
(Polygonurn pensylvanicum L.).
The primary
grass weeds in the weedy-checks included a mix of smooth
(Digitaria
ischaemum
(Schreb.) Schreb. ex Muhl.) and hairy crabgrass
(Digitaria
sanguinalis (L.)
Scop.), 75-85%, goosegrass
(Eleusine indica (L.)
Gaertn.), 15-20%, and less that
2.5%
of either Bermudagrass
(Cynodon
dactylon (L.)
Pers.) or barnyardgrass
[Echinochloa crus-galli (L.)
Beauv.].
All treatments receiving any weed control method had significantly
less weed cover than the weedy-check and the onion-free weedy check,
and the two weedy checks were not significantly different (Table 3). All
0
z
VI
0
VI
Q.
cz
U
0
00
!1
0
0
U
0
z
*
*
*
U)
z
—I
* * -
* * * 4
_* * * *
o • • * * *
* * * *
lu
U) * U) Cd
2z: z
>—* a *
o • * * *
U * * *
u IM
•0
U)
*
U)
rl
)
9Z* z
z
U) *
U)
z: z'
o
U)
z
U
)
*
V) rID
z
U,
a
z
- ,.-
o •
U)
*
U)
U z
CO
U)
*
U)
z: z
Gd
C.)
0
0
C'J
C
Cu
oJ
0
0
cJ
U)
a)
as
mc
V
C
Cu
(0
Ct
C/)
0)
C
as
•0
a)
()
0
a)
Ct
>
0
z
w
—J
I
co
24
CO
CO
C)
0
CO
0
.0
0
>
0
L)
12
'4-
CO
0
0
0
U
C000
•..
c'-
>
25
Qi
C
(D
E
cc
a)
0
4-
C
0
()
-D
a)
ci)
(0
0
C)
CIS
CD
a)
CD
>
cci
cci
a)
co
0
C
cci
a
c0
0
(I)
0)
C
ca
0
a)
a)
C
0
(ci
a)
0
0
a)
w
Ui
—J
CO
"C
CO
CO
• OS
rl
jCS
00C
'0
COCO
f 00
r4
c-4
CO
rj
CO-cC
r-
OoC.
c- r- VI
ci-
CO
- 0
000
10 10
ca w
r00
rn
OS CO
COCO
C)
In
'0
r-
t-
CO
CO CO.
eq
f
Cf
C)
CrC
II
0
0
('J
C
ca
cJ
0
0
c.'J
U)
co
I-
ci)
>.
(I)
U,
2
0
(ci
CD
C)
cc
I-
a,
>
(ci
1
co
(ci
U)
C)
C
(ci
a)
a,
C
0
(I)
C
a,
E
(ci
ci)
0
C
0
0
a,
a)
0
C.,
a,
w
6
w
-J
co
I-
0
C
0
C..)
0
C.)
C.)
C.. 00 C
CO
U
CO .0
.0 CO
.0 .0
CO
.0
N r
N- r-
C-
N
d s r- e- o C r- r- C C C C C
N N - C N N N
C
N- C- 00 C CfC 'C r-- CD C C
C
.-.
Y
00 00 00
4) M
,
-.L4 CO .0 .0 .0
CO U .0 .0
CO .0 CO .0 .0
C00NC'0_N_COCCCC
CC
QlzUU
CUU
0) 4) 4) C
CO C .0 U 0 .0 .0 .0
CO
.0 .0 CO
C
CO
CO C...
C - N
(I C' C C C C - C' C C C C
N C
N- 0000 ON 0'
C' C 00
C' 00 C C C
.,
C
VI
0..
CO
4)
O
C
ca CO
0
.000
0.
0)
)
4)24)
(2
4)-
.4)0)
0
05 .0
0 )
51
0 0
S
E
L
o
u
U OH
U O .
CO
(IC
(I,
.0
.0
0)
4) 4) 0)
4) 4)
0 0) 4)
CO CO .0 .0 C... C 0
C.) 4_
0)
Ce.. CO C... ( CO
O
'
II
CCCC
C
CC
C
Cd
C N - - -. - . C N - - C '0 C C '0
CO
.0 .0 .0 U 00 0)
U 00 C
C... 00 U C)
00 CO 00
00 CO
IC
.
mCC 00 .rCCC Cfl 0000
r1 - C - m N - C C r - m C N C C N
-
N
N'
-
o
C..
C.) 4) 0) C... '
0) 4) C... U 4) 4)
CO C... C...
CO
£2
00 N- 000 C 'ON 4 C r'C N - C N N C 00 C C 00
N N
CO
C C C C
C C
l
C C
C CI C
.
i
.
,i
- N
C
.r(IrC.rC
C---
C.
0000
0000
U,
4)
U
>o>
.0
C.)
OOOC
U.U.
4)COCOCOCO
.2.22.2.5.5.2.2
+.
0
C
0000
C
0
4
.
4)4)0)4)4)00) u 0
o
C/)
S E S
COCC
26
Webber, Shrefler, and Taylor
27
treatments receiving conventional herbicides resulted in significantly
less weed cover than the four CGM only treatments (Table 3).
Mid-season weed control (46 DAP).
All synthetic herbicide weed
control treatments resulted in fair (70% to 80%) to good (80% to 90%)
total and broadleaf weed control at 46 DAP (Table 3). Grass weed con-
trol was less than 70% for the lowest two rates of oxyfluorfen, com-
pared to over 70% control for any herbicide treatment containing
pendimethalin (Table 3). These results indicate that pendimethalin pro-
vided the best early season weed control.
Even with the very low weed pressure during the first half of the sea-
son, the three lowest CGM rates had very low weed control, less than
50% for total, broadleaf, and grass control (Table 3). The highest CGM
rate (4,000 kg-ha-
1
) maintained fair, 72.1%, total weed control and
good (82.7%), broadleaf weed control until 46 DAP. Although CGM
did provide initial weed control for onion, and more so for broadleaf
than grass weeds, additional weed control may be required.
Harvest weed cover.
At harvest there was a significant year
X
treat-
ment interaction for the broadleaf and grass weed cover and weed con-
trol data (Table 1); so these results will be discussed by year (Tables 4
and
5).
There was a 100% weed cover in the weedy-check treatments at har-
vest (Table 6). CGM treatments exhibited less than 1% total weed con-
trol at harvest, essentially no different from the weedy-checks. Even the
partial-season (weed free until 46 DAP) treatment had 99.3% weed
cover and less than 1% control at harvest (Table 6). This result indicates
the intense weed establishment and aggressive weed growth through the
crop cycle, even when onions are kept weed-free for the first 46 DAP.
The best residual weed control, although still very low, was in treat-
ments containing pendimethalin at 1.0 or 1
.5
kg-ha- ' ai, with'a slight in-
crease in weed control when tank-mixed with oxyfluorfen (Table 6).
Although the relative weed control advantages and disadvantages
continue across (Table 6) and within years (Tables 4 and 5) for total
weed control at harvest, the weed pressure differences for broadleaf and
grass weeds between years were involved in the significant year-
by-treatment interaction (Tables 4 and
5).
When comparing weed cover
at harvest between years, there is a general reversal between which
weed type, broadleaf or grass weeds, was predominant (Tables 4, 5)
even though there were no significant differences in weed cover at 46
DAP (Table 2). In both, years there was 100% weed cover in the
weedy-check at harvest, the distribution between broadleaf and grass
weeds was different between years (Tables 4, 5). In 2002, the broadleaf
ci
0
0
c'J
0
co
a)
Cl)
C)
C
al
'C
CD
a)
C
0
U,
C
a)
E
cts
a)
0
C
0
C)
'C
a)
a)
0
C)
a)
w
w
—j
I-
C)
U
.-
C.
'0 -. 'C 0) CO
C
CO 0) C...
0 (
"1 0
Cf
C
'f C/
0
fC C'
00 0 0 1 — 0 0 0 0 C
-- 00r
r'CN2
'00O
WC
'C'C'C'C C1'C'C'C CO'C'u om
l
i
Q 0 CO -C
CO
.0
0 0 0 0 0 0 0 0 0 0 0000 0 e"C 'l 0 0 000 C
0
0
U U U C,)
CO
U U U (0 C,) 0,0 CO U U U
CO
U
CO
U U
0 (f 00 00 ' 0 '
0000 r'l 000 (1 0
00
.0.0.0
.0
'0 U
'C 'C 'C
U U >
'C
.0.0 .0
'C
.0'0 (0,0
Ct, 00 0 CrC CrC 00 r'C
rn
0 00
fl
CrC 0 CrC 0 00
V
''0
CC - (
C
'0
4
0'0 ' N 00 N
I
T
r'l n
.,
CO
m
1(0
)0)UC)
?
0)
C)
00
(0
(0 CO 00
CO
CO
0 00U
,0 'C 00
'0 00'..
'C
C
SO
Cr)
00000
00 cn "(
r'
C'
(4
Sb
50
000, Cs
0000
50
CC) N CO
SC
C') 'C
— CO(0(0(0U(000COU(000,0Q(000 (00(00(0(0
0V0000o0©000000000
0
000
E-
2oo
O0'Cr
Q0C' C
OS OS
CS
C'
C'. 0'
C'
00
C)
CO
.12
—Ce
()0CC)ICC
0.
0---
0.
0000
0000
U
C)
C)
.0
C
U
'C
->- .E.2.ETh5.2
299 9
.00
.o
, ,
.9,0
0
C)
0
.2.2.2.2
+
0) C) t 0
0
(
SOL)N E E
E E EEU„,
'C
C
.:
0000
C C C
C
C
C
C
C0)_
Cr)
C
C
VI
C..
C
C)
C
C
- 0)0
C
0
(000
-A
'.0
CO
C_C
C)
E
(0
'0 0)
0)0)
C
(0” 0-
0 II
C
0
C C
E,,
U
CO
28
QU
UU
C)
U U
CD
UC
CD
U U L CD U
0 C r4 r 0
—0
0 O-
0
UC U
9
D U CD .0 CD V U -
CD CD
CD
CD
CD
CD
CD
CD
CD
U U
ra,C C
C C r 0 0 0 00 r
'0
c'l
NO' C'2 O'C' 0'
C(1
C'i
UUC.
U
U
U U U U CD.0.0 CD.C.0. (1 U U C)
CD
U
CD
U U
.0
C
_0_0
U
CCC
CD CDCD CD
U.0CD0 CD
CD
CDO CDCD CD0CD0
CD
CD
m
oq
C
rr-
oc
no
i
r CC - 000 — r- ., 0 c N 00 00000 r
.
0.
00 N
0'
00 CfC 10 N
N
00
0'
0'
00 N N
U
CO
.
.
CD&
0
U 0 00 00
"-j 00
00 00
U
.
L
L
ó
00CD0
00
C0.0 00_C_C
0CnC
i
CODCfl 'OC
0 '0 fl 0
0
0 0
13 CD CD
CD
U CD CD CD U CD-C CD U CD CD CD U CD U CD CD
0000 VCC 00
0
0 0000 N m 0000' N 00' 00000000
— — —
0\ 00 N 00 00 0' 0' 0' —
0 0 000
0
d o
Cl-
I
r4
m000000.hi
In 0
"1
In
0
-
+
U
0-
0000
-
+ .
g
Co
_?_ + 0) U
U 0) 0)
0)
0)
U 0 0 00
CD
W.
EE
UQUOOOOLLIQ.
LO
w
—j
Co
0
I
C
0
(-)
-C
0
d
VI
Eb
C.
U C
CD
U
C
r r-
-
•0
0
0)
U0
010
192
U
t
00)0)
U
so
C)
U
191
0
CD
U
c
II
-
i .9
29
I-
a)
>
0
C)
a)
a)
CO
-.0
Oc•%j
CO
(0 V
0) C
C
..
cJ
(a
'0
V
cj
a)
CO
a)cn
Ca)
o >
43
Co
co
(aa)
as
as
ci, 0)
o.
ow
cd
0_
— 0
LLIQ
(0
Wa)
-J
<C
0
0 r — 00 — 00'-
0'
0 c
'C 0'
000 000
.0.0
.0
0
0000' 00
C0'
Q -0
-000
m
0
.00
a'ooó
0
0' 00
0' 00 00
00000
0000
C
00000
II
0
—rl
+
0000
>
0000
U
0000
C)
.0
COCOCOCO
+.
0:
O 0 0
00 00
v
0
C)
j
u
o o
0000000
C
00
0
00
U
CO
C
0
.0
CO
C)
0.
0.
C
0
L)
•0
0
VI
o 0
CO
C)
C
C
C
0
-
0
CO
SC).
E
-
.
0 0
C CC)
0
2 E
Z
U. 0
-
II
0 C
0
Z
E
E
1
o
CO
C)
0
CO
C
.9
0
30
Webber, Shrefler, and Taylor
31
weed cover,
62.5%,
and grass weed cover, 37.5%, were reversed com-
pared to broadleaf and grass weed cover in 2003, 17.5% and 82.5%, re-
spectively. Not only were there no significant differences in weed cover
between years at 46 DAP for the weedy-check; but the weed cover de-
velopment from 46 DAP to harvest, as seen in the partial-season
weed-free treatment, was similar when comparing years for the broad-
leaf (29.8% vs. 28.3%) and grass cover (68.8% vs. 71.8%), 2002 and
2003, respectively (Tables 4, 5).
The primary environmental difference between years was higher pre-
cipitation in 2002, and the later planting date in 2003. It is unlikely that
delaying planting by 12 days in 2003 would result in such a reversal in
weed composition between years, especially when the differences were
not measurable at 46 DAP. It is more likely that differences in soil mois-
ture due to rainfall and irrigation between years, 2002
(53.8
cm rainfall)
and 2003 (19.8 cm rainfall or 26.2 cm with irrigation added) were re-
sponsible for seasonal differences in weed growth.
Even with the very low weed pressure during the first half of the sea-
son, the three lowest CGM rates had very low weed control-less than
50%
for total, broadleaf, and grass control. The highest CGM rate
(4,000 kg-ha- ) did maintain fair, 72.1%, total weed control and good,
82.7%, broadleaf weed control until 46 DAP. The synthetic herbicide
treatments resulted in significantly better weed control than the highest
and best CGM rate. When comparing the synthetic herbicides, pendi-
methalin provided the best early-season weed control.
The early effects of CGM were short-lived and essentially no differ-
ent from the weedy-check at harvest. The CGM material was no longer
visual on the soil surface at 46 DAP. The best residual weed control, al-
though still very low, was in treatments containing pendimethalin at 1.0
and 1.5 kg-ha-
1
ai, with a slight increase in weed control when tank-
mixed with oxyfluorfen. These results illustrate the importance of sea-
son-long weed control and the importance of additional mid-season
measures to provide season-long weed control. The post emergence
application of a synthetic graminicide such as sethoxydim (
2
-[
l
-
1-one) and fluazifop ((R)-2- { 4[5(trifluoromethyl)-2-pyridylOXy]phen-
oxy}propionic acid) would certainly provide significantly greater grass
control. In an organic production system, the post-directed of applica-
tion of organically certified contact herbicides have the potential to en-
hance the season long weed control in transplanted onions.
32
INTERNATIQURNAL OF VEGETABLE SCIENCE
LITERATURE CITED
Ahrens, W. H. (ed.). 1994. Herbicide handbook 7th ed., Weed Sci. Soc. America,
Champaign, Ill.
Bell, C. E. and B. E. Boutwell. 2001. Combining bensulide and pendimethalin controls
weeds in onions. Calif. Ag.
55(1):35-38.
Bingaman, B. R. and N. E. Christians.
1995.
Greenhouse screening of corn gluten meal
as a natural control for broadleaf and grass weeds. HortScience 30:1256-1259.
Christians, N. E. 1991. Preemergence weed control using corn gluten meal. U.S. Patent
No. 5,030,268.
Christians, N. E. 1993. The use of corn gluten meal as a natural preemergence weed
control in turf. Intl. Turfgrass Soc. Res. J. 7:284-290.
Christians, N. E. 1995. A natural herbicide from corn meal for weed-free lawns. The
IPM Pract. 17(10):5-8.
Cudney, D. W. and S. B. Orloff. 1988. Russian thistle,
Salsola iberica,
control in onion
(A/hum cepa).
Weed Tech. 2:375-378.
Dunan, C. M., P. Westra, F. Moore, and P. Chapman. 1996. Modeling the effect of
duration of weed competition, weed density and weed competitiveness on seeded,
irrigated onion. European Weed Res. Soc., Weed Res. 36:259-269.
McCraw, D. 1990. Growing dry bulb onions from fall seeding in Oklahoma. Proc.
Okla. Hort Industries Show. 9:176-178.
McDade, M. C. 1999. Corn gluten meal and corn gluten hydrolysate for weed control.
MS Thesis., Dept. of Horticulture, Iowa State Univ., Ames, Iowa.
McDade, M. C, and N. E. Christians. 2000. Corn gluten meal - a natural pre-emergence
herbicide: effect on vegetable seedling survival and weed cover. Amer. J. Altern.
Agricult. 15(4):189-191.
Motes, J. E. and W. Roberts. 1994. Fertilizing commercial vegetables. Oklahoma State
University, OSU Extension Facts, F-6000.
Quarles, W. 1999. Corn gluten meal: a least-toxic herbicide. The IPM Pract. 2
1(5/6):
1-7.
Sharp, D. (ed.). 2002. Weed control manual. Meister Pub. Co., Willoughby, OH.
Shrefler, J. 2001. Onion production in Oklahoma. Proc. Okla.-Ark. Hort Industries
Show. 20:106-107.
Shrefler, J. 2002. Onion production and variety selection. Proc. Okla.-Ark. Hon Indus-
tries Show. 21:125-126.
Shrefler, J. 2004. Onion variety selection, sources and quality. Proc. Okla.-Ark. Hort
Industries Show. 23:140-141.
Shrefler, J., S. Upson, and S. McClure. 2004. First year experience with hoop-house
grown onion transplants. Proc. Okla.-Ark. Hort Industries Show. 23:142-143.
Sieczka, J. B., J. F. Creighton, and W. J. Sanok. 1982 Results of onion weed control ex-
periments on mineral soil - Long Island. Veg. Crops Dept., Cornell Univ., Ithaca,
NY, Paper #808.
Singh, S., R. K. Malik, and J. S. Samdyan. 1992. Evaluation of herbicides for weed con-
trol in onion
(A/hum cepa L.).
Tests Agrochem. Cult.
13:54-55.
Umeda, K., G. Gal, and B. Strickland. 1998. Evaluation of preemergence herbicides for
onion weed control. 1998 Vegetable Report, College of Agriculture, Univ. of An-
Webber, Shrefler, and Taylor
33
zona, Tucson, Ariz. (available on-line at: http://ag.arizona.eduJpUbS/CrOPS/azl
101/
azi 101_12.html).
Westra, P., C. H. Pearson, and R. Ristau. 1990. Control of Venice mallow (Hibsicus
trionum)
in corn
(Zea mays)
and onions
(A Ilium
cepa).
Weed Tech. 4:500-504.
Wicks, G. A., D. N. Johnson, D. S. Nuland, and E. J. Kinbacher. 1973. Competition be-
tween annual weeds and sweet Spanish onions. Weed Sci. 21(5):436-439.
doi: 10.1 3005512v I 3n03_03
For FACULTY/PROFESSIONALS with journal subscription
recommendation authority for their institutional library...
If you have read a reprint or photocopy of this article, would you like to
make sure that your library also subscribes to this journal? If you have
the authority to recommend subscriptions to your library, we will send you
a free complete (print edition) sample copy for review with your librarian.
1.
Fill out the form below and make sure that you type or write out clearly both the name
of the journal and your own name and address. Or send your request via e-mail to
getinfo@haworthpress.com
including in the subject line 'Sample Copy Request" and
the title of this journal.
2.
Make sure to include your name and complete postal mailing address as well as your
institutional/agency library name in the text of your e-mail.
(Please note: we cannot mail specific journal samples, such as the issue in which a specific article appears.
Sample issues are provided with the hope that you might review a possible sub c'ption/e-subscriptiOfl with
your institution's librarian. There is no charge for an institution/campus-wide electronic subscription
-
concurrent with the archival print edition subscription.]
L YE51
Please send me a complimentary sample of this journal:
(please write complete journal title here-do not leave blank)
I will show this journal to our institutional or agency library for a possible subscription.
Institution/Agency Library:
Name:
Institution:
Address:
City: ____________________ State: __________ Zip:
Return to: Sample Copy Department, The Haworth Press, Inc.,
10 Alice Street, Binghamton, NY 13904-1580
... Onion (Allium cepa L.) is not competitive against weeds 1,2,3 , due to slow growth rate, short stature, non-branching plant structure, low leaf area, shallow root system, thin canopy and the cylindrical upright leaves do not shade the soil to suppress weed growth 4,5 . Uncontrolled weeds in onion decrease bulb yield by 61.4% 4 ; 92.3% 6 with up to 100% unmarketable bulbs from un-weeded plots 6 . ...
... The conventional method of weed control, hand-weeding, is costly and difficult due to close planting. Mechanical weed control is useful for controlling weeds between rows but ineffective for controlling weeds within rows 5 . Natural, or nonsynthetic, herbicides availability is increasingly limited in many vegetable crops, with tightening restriction on their usage. ...
... Onion (Allium cepa L.) is not competitive against weeds 1,2,3 , due to slow growth rate, short stature, non-branching plant structure, low leaf area, shallow root system, thin canopy and the cylindrical upright leaves do not shade the soil to suppress weed growth 4,5 . Uncontrolled weeds in onion decrease bulb yield by 61.4% 4 ; 92.3% 6 with up to 100% unmarketable bulbs from un-weeded plots 6 . ...
... The conventional method of weed control, hand-weeding, is costly and difficult due to close planting. Mechanical weed control is useful for controlling weeds between rows but ineffective for controlling weeds within rows 5 . Natural, or nonsynthetic, herbicides availability is increasingly limited in many vegetable crops, with tightening restriction on their usage. ...
Research
Full-text available
Onion (Allium cepa L.) does not compete well with weeds, especially at the early stage of growth; relatively weed-free conditions are required for successful production. Allelopathy may have a beneficial role in weed control and crop production. Shortage of hand labor and avoidance of synthetic herbicides makes weed control in onion difficult. Response of weeds to allelopathy may vary according to plant species, plant parts and thickness of mulch used. The study was conducted using organic mulches: sawdust (SD), rice straw (RS), burclover weed (CW) or cogongrass (CG) in comparison with hand hoeing (HH) and the herbicide butralin+1 hoeing (BUH) on growth, bulb nutrient concentration, yield, and quality of onion plants and control of associated weeds. Weed density responded differently to mulches. Lolium multiflorum Lam. was affected less compared to broadleaved weeds. Application of SD, RS, CW, CG, HH and BUH, decreased total weed dry weight at 75 days after onion transplanting by 42, 51, 62, 63, 92 and 98%, respectively. All mulch treatments require an additional hand weeding after 60 days from transplanting. Weed competition caused decreased onion plant dry weight (43-56%), bulb diameter (44%) and marketable yields (65.5%). The CV mulch allowed onion to produce the highest marketable yield. The CW efficacy control was less (up to 62%) compared to HH (98%). Organic mulch are effective for weed control and could be a potential alternative to synthetic herbicides, hoeing or hand removal of weeds in onion organic farming. Further studies are needed to evaluate if combinations of mulches can provide better control than each individually, their side effects on beneficial organisms diseases, and insects and the effectiveness of these mulches under organic production system.
... Onion (Allium cepa L.) is not competitive against weeds 1,2,3 , due to slow growth rate, short stature, non-branching plant structure, low leaf area, shallow root system, thin canopy and the cylindrical upright leaves do not shade the soil to suppress weed growth 4,5 . Uncontrolled weeds in onion decrease bulb yield by 61.4% 4 ; 92.3% 6 with up to 100% unmarketable bulbs from un-weeded plots 6 . ...
... The conventional method of weed control, hand-weeding, is costly and difficult due to close planting. Mechanical weed control is useful for controlling weeds between rows but ineffective for controlling weeds within rows 5 . Natural, or nonsynthetic, herbicides availability is increasingly limited in many vegetable crops, with tightening restriction on their usage. ...
Article
Full-text available
Onion (Allium cepa L.) does not compete well with weeds, especially at the early stage of growth; relatively weed-free conditions are required for successful production. Allelopathy may have a beneficial role in weed control and crop production. Shortage of hand labor and avoidance of synthetic herbicides makes weed control in onion difficult. Response of weeds to allelopathy may vary according to plant species, plant parts and thickness of mulch used. The study was conducted using organic mulches: sawdust (SD), rice straw (RS), bur-clover weed (CW) or cogongrass (CG) in comparison with hand hoeing (HH) and the herbicide butralin+1 hoeing (BUH) on growth, bulb nutrient concentration, yield, and quality of onion plants and control of associated weeds. Weed density responded differently to mulches. Lolium multiflorum Lam. was affected less compared to broadleaved weeds. Application of SD, RS, CW, CG, HH and BUH, decreased total weed dry weight at 75 days after onion transplanting by 42, 51, 62, 63, 92 and 98%, respectively. All mulch treatments require an additional hand weeding after 60 days from transplanting. Weed competition caused decreased onion plant dry weight (43-56%), bulb diameter (44%) and marketable yields (65.5%). The CV mulch allowed onion to produce the highest marketable yield. The CW efficacy control was less (up to 62%) compared to HH (98%). Organic mulch are effective for weed control and could be a potential alternative to synthetic herbicides, hoeing or hand removal of weeds in onion organic farming. Further studies are needed to evaluate if combinations of mulches can provide better control than each individually, their side effects on beneficial organisms diseases, and insects and the effectiveness of these mulches under organic production system.
... Although mechanical weed control through cultivation is useful for controlling weeds between rows, it is not effective for controlling weeds between plants within rows. Although corn gluten meal shows great promise as an organic preemergent herbicide for onions (Webber et al., 2006;Webber et al., 2007a), research has shown the need for supplemental, postemergent, weed control once early season effectiveness of corn gluten meal diminishes (Webber et al., 2007b). Organic onion producers need additional organic herbicides that can affectively provide post-emergent weed control. ...
Conference Paper
Full-text available
Identifying concomitant hosts for onion thrips, Thrips tabaci, and Iris yellow spot virus (IYSV) is a critical step in determining the role that such hosts play in the epidemiology of IYSV in onion fields and subsequent management strategies. The primary objective of our project was to identify sources of IYSV in New York’s onion cropping system by examining the following: (1) onion plants imported from Arizona for transplanting, (2) onion bulbs imported for repackaging, (3) volunteer onion plants collected from the previous season’s onion fields, (4) volunteer onion plants collected from cull piles, and (5) weeds. A related objective was to identify weed species that serve as a reproductive host for T. tabaci. A host plant with both T. tabaci larvae and IYSV is likely important in the epidemiology of this disease because IYSV can only be acquired by immature thrips. Both objectives were addressed in studies conducted throughout commercial onion fields in New York in 2007 and 2008. IYSV was detected in volunteer onion plants growing in the previous year’s onion fields and cull piles as well as selected weed species, such as curly dock and dandelion. Immature onion thrips also were found on these weed species. Among these three sources, weeds may contribute the most to annual spread of this disease because their densities far outnumber densities of volunteer onions in the onion-cropping system. However, more research is needed to examine this hypothesis. Elucidating temporal and spatial relationships between IYSV, weed hosts, onion thrips and the onion crop should prove critical for identifying onion fields at risk for IYSV and deployment of management strategies. Thousands of onion plants imported from Arizona for transplanting in New York tested negative for IYSV, and therefore are not likely a source. Imported bulbs discarded into cull piles during repackaging could be a source, but not likely a major one. We learned this summer that many imported bulbs do not sprout even when provided conditions to do so; perhaps these bulbs were treated with a sprout inhibitor prior to harvest. If imported bulbs never produce foliage to support thrips development, transference of IYSV to nearby onion fields cannot occur. Additionally, cull piles are small, concentrated areas of which many are located great distances from onion fields.
... The current research is consistent with the application of corn gluten meal to direct-seed vegetables (black bean (Phaseolus vulgaris L.), pinto bean, cantaloupe, and watermelon by Webber et al. (2008). Further research should address banded applications of MSM with either established direct-seeded or transplanted cucurbits, or other vegetable crops in the same manner as others have done with corn gluten meal (Boydston et al., 2011;Webber & Shrefler, 2006;Webber et al., 2007). ...
Article
Full-text available
Weed control in organic production systems can be a labor intensive and expensive process. Mustard seed meal (MSM) is phytotoxic and a potential pre-emergent and preplant-incorporated organic herbicide for controlling germinating and emerging weed seedlings: unfortunately, MSM may also adversely impact seedling survival of certain direct-seeded vegetable crops. Field research was conducted in southeast Oklahoma (Lane, OK) to determine the phytotoxic impact of MSM on indigenous weeds and seedling establishment of cantaloupe (Cucumis melo L.) var. ‘PMR-45’, cucumber (Cucumis sativus L.) var. ‘Marketmore 76’, yellow squash (Cucurbita pepo L.) var. ‘Crookneck’, and watermelon (Citrullus lanatus L.) var. ‘Dixie’. The factorial experiment included 2 MSM incorporation levels (no incorporation and incorporation), 2 MSM application rates (2.25 and 4.5 mt/ha), 2 application patterns (banded and solid), 2 experimental control treatments (1 for each incorporation method) and four replications. The soil [Bernow fine sandy loam, 0-3% slope (fine-loamy, siliceous, thermic Glossic Paleudalf)] was prepared for planting by plowing, fertilizing, and forming raised beds. MSM was applied to raised beds 3 m-long on 0.76 m-centers. The banded application produced a 10.2 cm-wide MSM-free area in the bed center where the crop would later be direct-seeded. The MSM was then either left on the surface or incorporated into the top 2.5-5.0 cm and then direct-seeded with cantaloupe, cucumber, yellow squash, and watermelon. Plant stands and weed control ratings were collected during the experimental period. Twenty-eight days after planting, the entire plot was harvested and the fresh and dry plant weights determined. Although applications of MSM provided sufficient broadleaf, grass, and total weed control, cucurbit establishment and development, the application of MSM at 2.25 and 4.5 mt/ha severely reduced crop establishment of direct-seeded cucurbits. Further research should address banded applications of MSM with either established direct-seeded or transplanted cucurbits and other vegetable crops in the same manner as others have done with corn gluten meal.
... Applying organic fertilizers at the time of post-emergence abrasiveweeding may also reduce in-row weed competition by delaying N availability until periods of peak crop demand (Liebman and Davis, 2000). Moreover, some seed meal fertilizers may have allelopathic properties that can aid in the inhibition of weed seed germination and growth after grit application, similar to a pre-emergence herbicide (Bingaman and Christians, 1995;Boydston et al., 2011;Webber et al., 2008). ...
Article
Abrasive-weeding is a novel weed management tactic with potential to reduce tillage and hand-weeding in organic agriculture. However, abrasive-weeding has not been tested in vegetable cropping systems and growers are interested in the potential for using organic fertilizers as abrasive grits to control weeds and supplement crop nutrition in one field pass. A two-year field study was conducted at the University of Illinois Sustainable Student Farm to determine the effect of air-propelled abrasive grit type, including organic fertilizers, and application frequency on weed density and biomass and crop yield and marketability in organic tomato (Solanum lycopersicum L.) and pepper (Capsicum annuum L.) cropping systems. Abrasive-grits, including granulated walnuts shells and maize cobs, greensand fertilizer, and soybean meal, were applied via compressed air between one and four times within planting holes of plastic mulch. Weed density was quantified 25 or 37 days after the first application and weed biomass was harvested at the end of the growing season. Tomatoes and peppers were harvested ripe and graded for marketability. Two applications of abrasive grits, regardless of grit type, reduced weed density by 63% and 80% in tomato and pepper, respectively. Broadleaf weeds were more susceptible to abrasive-weeding than grass weeds. Abrasive-weeding reduced final weed biomass by 69-97% compared with the weedy control, regardless of grit type or application frequency. Total tomato yield was up to 44% greater in treated plots compared with the weedy control, whereas total yield gains in pepper (up to 33%) were only approaching significance (p = 0.09). Yield and the marketability of fruit was not negatively affected by grit application, despite minor stem and leaf tissue damage after applications. Organic fertilizers used as abrasive grits in this study could contribute between 35 and 105 kg N ha-1, which may improve the functionality and economic feasibility of abrasive-weeding.
... Seedling Emergence. Inconsistencies in the herbicidal efficacy of Brassicaceae seed meal and corn gluten meal on seedling emergence across weed species have been reported (Abouziena et al. 2009;Boydston et al. 2008;Handiseni et al. 2011;Nonnecke and Christians 1993;Rice et al. 2007;Russo and Webber 2012;Webber et al. 2007). Because weed seedling emergence was similar with CGM and MSM for each weekly count, only weed seedling emergence 28 d after planting is presented. ...
Article
Full-text available
Corn gluten meal (CGM) and white mustard seed meal (MSM) can release biologically active allelochemicals and have been demonstrated to be useful as PRE alternative weed control products. The objective of this study was to compare the effects of CGM and MSM on the emergence and aboveground dry weight of five broadleaf and two grass weed species. Greenhouse experiments were conducted using 26 by 53 cm plastic trays filled with a mix of field soil and potting soil (4:1 by wt). CGM and MSM were mixed with 1.5 kg of soil mix and applied at rates equivalent to 2,240, 4,480, and 6,720 kg ha-1. Overall, MSM was more effective than CGM for controlling weeds. Averaged over application rates and compared to the nontreated control, emergence rates were 17, 27, and 34% for kochia, common lambsquarters, and barnyardgrass, respectively, in CGM-amended soil, and 14, 13, and 6% for kochia, common lambsquarters, and barnyardgrass, respectively, in MSM-amended soil. Averaged over application rates, green foxtail and common lambsquarters aboveground dry biomass were 40 and 25% of the nontreated control, respectively, in CGM-amended soil. Green foxtail and common lambsquarters shoot biomass in MSM-amended soil was 13 and 5% of the nontreated control, respectively. Significant interactions were observed for meal by rate on redroot pigweed seedling emergence and redroot pigweed, barnyardgrass (Moscow), and annual sowthistle (Moscow) aboveground dry biomass. These interactions can be attributed to the fact that herbicidal effects were less evident in response to higher application rates using MSM compared to higher CGM application rates. Overall, this greenhouse study indicates MSM is more effective than or at least equal to CGM for broadleaf and grass weed control at the same application rate.
... Moreover, some organic fertilizers may have herbicidal properties that can aid in the inhibition of weed seed germination and growth. Previous studies have demonstrated significant reductions in weed emergence and biomass following soil application of mustard seed meal and corn gluten meal (Bingaman and Christians 1995;Boydston et al. 2011;Webber, III et al. 2008). Despite the fertility benefits and herbicidal potential of some organic fertilizers, none have been tested as abrasive grits in vegetable crops. ...
Article
Abrasive weed control is a novel weed management tactic that has great potential to increase the profitability and sustainability of organic vegetable cropping systems. The objective of this study was to determine the effect of air-propelled organic abrasive grits (e.g., organic fertilizers) on weed seedling emergence and growth and vegetable crop growth. A series of thirteen greenhouse trials were conducted to determine the susceptibility of weeds to abrasive weed control with one of six organic materials including: corn cob grits, corn gluten meal, greensand fertilizer, walnut shell grits, soybean meal, and bone meal fertilizer. In addition, crop injury was quantified to determine the potential utility of each organic material as abrasive grits in tomato and pepper cropping systems. Of the six organic materials, corn gluten meal, greensand fertilizer, walnut shell grits, and soybean meal provided the broadest range of POST weed control. For example, one blast of corn gluten meal and greensand fertilizer reduced Palmer amaranth (one-leaf stage) seedling biomass by 95 and 100% and green foxtail (one-leaf stage) biomass by 94 and 87%, respectively. None of the organic materials suppressed weed seedling emergence when applied to the soil surface, suggesting that residual weed control with abrasive grits is unlikely. Tomato and pepper stems were relatively tolerant of abrasive grit applications, though blasting with select materials did increase stem curvature in tomato and reduced biomass (corn cob grit) and relative growth rate (corn gluten meal and greensand) in pepper. Results suggest that organic fertilizers can be effectively used as abrasive grits in vegetable crops, simultaneously providing weed suppression and supplemental crop nutrition. Field studies are needed to identify cultural practices that will increase the profitability of multifunctional abrasive weed control in organic specialty crops.
Article
Full-text available
Corn gluten meal (CGM) has been used as a supplement for livestock feeding due to its high concentration of digestible nitrogen (N) compounds. Heat damaged CGM (HDCGM), which is not suitable for livestock feeding, may still have value as an organic fertilizer. Objective of the study was to evaluate the impacts of non-feed grade HDCGM on forage production from annual cool and warm season grasses and soil characteristics. Pre-plant incorporated HDCGM at 3 Mg/ha was compared with 4.2 Mg/ha poultry litter (POTL), and 160 kg/ha commercial N fertilizer (COMF), and zero fertilizer (ZERO) for production of the cool-season ‘Prine’ annual ryegrass (Lolium multiflorum), and the warm-season ‘Greentreat’ sorghum × sudangrass (SS) hybrid (Sorghum bicolor). The treatments were repeated at the same site on December 3, 2010 (planted annual ryegrass), May 26, 2011 (planted SS hybrid), October 24, 2011 (planted annual ryegrass) and May 18, 2012 (planted SS hybrid). The HDCGM had 68% more N concentration than POTL, while its P, K, Mg, and Ca were less than half in POTL. The residual N concentration in buried HDCGM and POTL increased in a similar pattern with time in soil. The HDCGM produced less dry matter (DM) of annual ryegrass and SS hybrid than POTL; however, the differences between the two treatments were not statistically significant. All treatments produced more DM in the second than first year. After two years of field test, soil receiving HDCGM contained higher soil organic matter (OM) and N than receiving POTL. Although not as beneficial as POTL for DM production, HDCGM showed potential value as a slow release fertilizer to improve DM production and soil characteristics.
Article
Weed control in organic peanut is difficult and lack of residual weed control complicates weed management efforts. Weed management systems using corn gluten meal in combination with clove oil and sweep cultivation were evaluated in a series of irrigated field trials. Corn gluten meal applied in a 30 cm band over the row at PRE, sequentially at PRE+2 wk after emergence, and PRE+2wk+4wk did not adequately control annual grasses and smallflower morningglory. Similarly, a banded application of clove oil applied POST did not adequately control weeds. The only treatment that improved overall weed control was sweep cultivation. Peanut yields were not measured in 2006 due to heavy baseline weed densities and overall poor weed control. Peanut yields were measured in 2007 and were not affected by any weed control treatment due to poor efficacy. While sweep cultivation improved weed control, weeds were controlled only in the row middles and surviving weeds in-row reduced peanut yield. Even when used in combination with sweep cultivation, corn gluten meal and clove oil were ineffective and offer little potential in a weed management system for organic peanut production. Nomenclature: Clove oil; corn gluten meal; crowfootgrass, Dactyloctenium aegyptium (L.) Willd.; goosegrass, Eleusine indica (L.) Gaertn.; smallflower morningglory, Jacquemontia tamnifolia (L.) Griseb.; southern crabgrass, Digitaria ciliaris (Retz.) Koel.; Texas millet, Urochloa texana (Buckl.) R. Webster; peanut, Arachis hypogaea L.
Article
Full-text available
Corn ( Zea mays L.) gluten meal (CGM) was evaluated under greenhouse conditions for efficacy on 22 selected monocotyledonous and dicotyledonous weed species. Corn gluten meal was applied at 0, 324, 649, and 973 g·m –2 and as a soil-surface preemergence (PRE) and preplant-incorporated (PPI) weed control product. CGM reduced plant survival, shoot length, and root development of all tested species. Black nightshade ( Solanum nigrum L.), common lambsquarters ( Chenopodium album L.), creeping bentgrass ( Agrostis palustris Huds.), curly dock ( Rumex crispus L.), purslane ( Portulaca oleracea L.), and redroot pigweed ( Amaranthus retroflexus L.) were the most susceptible species. Plant survival and root development for these species were reduced by ≥75%, and shoot length was decreased by >50% when treated PRE and PPI with 324 g CGM/m ² . Catchweed bedstraw ( Galium aparine L.), dandelion ( Taraxacum officinale Weber), giant foxtail ( Setaria faberi Herrm.), and smooth crabgrass [ Digitaria ischaemum (Schreb.) Schreb. ex Muhl] exhibited survival and shoot length reductions >50% and an 80% reduction in root development when treated with PPI CGM at 324 g·m –2 . Barnyardgrass [ Echinochloa crus-galli (L.) Beauv.] and velvetleaf ( Abutilon theophrasti Medic.) were the least susceptible species showing survival reductions ≤31% when treated with 324 g CGM/m ² .
Article
Full-text available
DCPA was the principal preemergence herbicide for controlling weeds in onions until its manufacture was discontinued in 1996, although it may be reintroduced in 2001. The purpose of this research was to test the effectiveness of a combination of two herbicides, bensulide and pendimethalin, as a replacement weed-control treatment. Results are encouraging; this combination performed as well as DCPA in 12 onion field trials conducted in the Imperial Valley. Onion yields in fields treated with bensulide and pendimethalin were comparable to that of fields treated with DCPA.
Article
Full-text available
In a study involving the use of food-grade corn meal as a growth media for microorganisms, it was observed that stand establishment of creeping bentgrass seedlings was reduced by the incorporation of corn meal into the soil. Studies on the effect of adding corn starch, corn gluten meal, corn germ, corn seed fiber, or corn meal to the soil surface before seeding creeping bentgrass ( Agrostis palustris Huds.) demonstrated that the greatest concentration of the inhibitory substance responsible for stand reduction was in the corn gluten meal. Further studies have shown that corn gluten meal contains a substance that inhibits root formation in several species, including crabgrass (Digitaria spp.). Gluten meal is the protein fraction of the corn extracted in the wet-milling process and is used as an animal feed. It contains approximately 10% nitrogen (N) by weight and makes a good natural fertilizer for turf. In field studies on the effect of corn gluten meal on crabgrass control, larger amounts were required when the material was applied 4 weeks before crabgrass germination than when it was applied 1 week before germination. Corn gluten meal applied at 99, 198, 297, 396, 495, and 594 g m -2
Article
Postemergence herbicides alone and in combination were evaluated for Venice mallow control in corn and onion in Colorado during 1986 and 1987. Season-long control of 88 to 98% in corn was obtained with bromoxynil plus cyanazine or atrazine; 2,4-D amine plus dicamba or bromoxynil; or linuron, bromoxynil, or dicamba applied alone. Oxyfluorfen plus bromoxynil in a split application controlled Venice mallow 80 to 99% all season in onions. Uncontrolled Venice mallow caused higher yield reductions in onions than in corn.
Article
The effectiveness of oxyfluorfen and bromoxynil for Russian thistle control in onion was measured in a 2-yr study conducted in the high desert region of southern California. Oxyfluorfen, bromoxynil, or combinations of the two applied one at the 2-leaf growth stage of onion did not control Russian thistle. When a first application was followed 14 days later with a second herbicide application, a first application of oxyfluorfen plus bromoxynil was most effective. Oxyfluorfen applied alone as a second application was least effective, but bromoxynil alone plus oxyfluorfen improved control. Adding petroleum oil to oxyfluorfen plus bromoxynil improved Russian thistle control.
Article
The competitiveness of annual weeds in irrigated sweet Spanish onions ( Allium cepa L.) was studied at North Platte, Nebraska, during 1969 and 1970. Weeds allowed to grow in the row for 2, 4, 6, and 8 weeks after onion emergence reduced onion yields 20, 20, 40, and 65%, respectively. When plots were kept weed-free until onion emergence and 2, 4, 6, 8, 10, and 12 weeks after emergence, onion yields were reduced 100, 99, 87, 75, 46, 25, and 5%, respectively. Redroot pigweed ( Amaranthus retroflexus L.), kochia ( Kochia scoparia L.), and grass weeds accounted for 54, 21, and 21%, respectively, of the total weed yield.
Article
At three test sites, ethofumesate (Nortron ®) at 1.0 and 2.0 lb AI /A was safe on onions. Nortron appeared to provide marginal control of light to moderate weed infestations of London rocket (Sisymbrium irio) at two sites. Pendimethalin (Prowl ®) at 0.50 and 0.75 lb Al/A was safe on onions at two sites with furrow irrigation. At three sites with sprinkler irrigation, Prowl treatments caused as high as 62 to 88% stand reduction when sprinklers were used to incorporate the herbicide. Bensulide (Prefar0) injured onions at early rating dates and height measurements indicated that the plants were shortened relative to the untreated check. End of the season visual observations showed that onions had grown out of the initial injury and the crop did not appear to be damaged. Prefar combined with Prowl or Nortron was more injurious to onions with sprinkler irrigation than with furrow irrigated incorporation. Prefar gave marginal weed control in the tests under conditions with low weed infestations. Lactofen (Cobra ®) was injurious to onions at all five test sites and caused significant crop stand reduction. Combination treatments of Prowl with DCPA (Dacthal ®) or Prefar were damaging to onions under sprinklers but injury was minimal with furrow irrigations. Metolachlor (Dual ®) and dimethenamid (Frontier®) caused minimal injury and no stand reduction of onions under sprinklers but with furrow irrigation, the stand was reduced and height reduction was substantial. The series of field tests demonstrated that herbicide performance was significantly influenced by irrigation practices. Prowl herbicide was extremely injurious and caused substantial crop stand reduction with sprinkler irrigation. Dual and Frontier exhibited less injury on onions under sprinklers than with furrow irrigation.
Article
Weeds are considered the most important pest group for farmers interested in lowering external inputs and avoiding synthetic chemical use. Corn gluten meal (CGM) is a natural preemergence weed control used in turfgrass, which reduces germination of many broadleaf and grass weeds. The objective of this study was to investigate weed cover and vegetable seedling survival in field plots when CGM is incorporated before planting. Three studies were conducted, with three replications for each study. Five rates of powdered CGM (0,100, 200, 300, and 400 g m–2) were weighed and incorporated into the top 5–8 cm of soil in recently disked 1.5-m by 2.7-m plots. Seeds of eight vegetables were each planted in rows 1.4 m long and 0.3 m apart. Seedling survival and percentage of weed cover were recorded for each plot. Corn gluten meal at rates of 100, 200, 300, and 400 g m–2 reduced mean weed cover by 50, 74, 84, and 82%, respectively, compared with the control. Seedling survival at 100 g CGM per m2 was reduced by 67% for ‘Comanche’ onion, 35% for ‘Ruby Queen’ beet, 41% for ‘Red Baron’ radish, 71% for ‘Provider’ bean, 73% for ‘Scarlet Nantes’ carrot, 59% for ‘Maestro’ pea, and 68% for ‘Black Seeded Simpson’ lettuce, compared with the control. Seedling survival for ‘Daybreak’ sweet corn was not reduced by rates of 100 or 200 g CGM per m2, but was reduced by 26% at a rate of 300 g CGM per m2 compared with the control. Because of the reduction in seedling survival at even the lowest rate of CGM (100 g m–2), direct seeding of these vegetables into soil into which CGM has been incorporated is not advisable. Using transplants may be an alternative that takes advantage of the herbicidal effects of CGM and the nitrogen it provides.
Article
Weed removal experiments were conducted in growers' fields in northern Colorado to assess the effect of duration of competition, weed density, weed competitiveness and crop density on irrigated seeded onion (Allium cepa L.). Duration of competition, expressed in thermal time units (TTUs) with a base of 7.2^C, explained 65% of the variation in the reduction of onion relative yield. The first significant reduction in onion relative yield was at 90 TTUs, averaged over weed load (weed density adjusted by competitiveness) and onion density. A polynomial multiple regression model, accounting for duration of competition and weed load, explained 75% of the variation in onion relative yield. A non-linear multiple regression model, combining a gamma function response of relative yield to duration of competition plus a hyperbolic response of relative yield to weed load, was as good a predictor and a better description of the system. Onion relative yield was more sensitive to the duration of weed competition than to weed load. Bulb size class distribution and the resulting average onion price were affected by weed competition. Polynomial models were used to describe changes in bulb size class proportions as a function of duration of competition, weed load and onion density.