Date

0-7639

mpg—1'“

Ln$?AifiY
Michigan State
University

 

 

 

 

This is to certify that the

thesis entitled

WEED CONTROL STRATEGIES FOR TILL-
PLANTED FIELD CROPS IN RIDGES

presented by

Geoffrey Allen List

has been accepted towards fulfillment
of the requirements for

M.S. degree in Crop 8. Soil Sciences

 

 

QGWO A/LZV ll

4professor

 

3/13/86

MS U is an Affirmative Action/Equal Opportunity Institution

 

 

 

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NEED CONTROL STRATEGIES FOR TILL-PLANTED FIELD CROPS IN RIDGES

By

Geoffrey Allen List

A THESIS

Submitted to
Michigan State University
in partial fulfillment of the requirements
fer the degree of

MASTER OF SCIENCE

Department of Crop and Soil Sciences

1986

ABSTRACT

NEED CONTROL STRATEGIES FOR TILL-PLANTED FIELD CROPS ON RIDGES

By
Geoffrey Al l en Li st

The contribution of herbicides and cultivation were examined as
components of a total weed control strategy in corn (_Z__e_e_1_ gays L.) and
soybeans (Glycine max (L.) Merr.) till-planted on ridges. Sequential
applications with preemergence herbicide applications preceded by an
early preplant application or followed by a layby application provided
the most consistent season-long control of annual weeds. Under
conditions of inadequate rainfall, early preplant applications in till-
planted soybeans provided equal or greater weed control and cr0p
tolerance than preemergence application of the same herbicides. Banded
applications of herbicides, fol lowed by one cultivation, provided

control of common ragweed (Ambrosia artemisiifolia L.) in soybeans and

 

common lambsquarters (Chenopodium album L.) in both crops and was not

 

significantly different from broadcast treatments at any level of
cultivation. No significant differences in yield were observed in

either cr0p due to differences in herbicide programs or cultivation.

 

To Teresa

1'1

ACKNOHLEDGEMENTS

I would like to express my sincere thanks to all the members of my
graduate committee, Dr. William F. Meggitt, Dr. Donald R. Christenson,
and Dr. Robert H. Wilkinson, for their invaluable advice and insight in
the planning and completion of this project. My association with all
of you made this learning experience complete. A special thanks to Dr.
Meggitt for allowing me the Opportunity to continue my education.

I am most indebted to Dr. James J. Kells for his steadfast and
diligent support of all aspects of my program of study. As my faculty
advisor, his guidance throughout this research project was greatly
appreciated. Without his enduring patience and helpful ideas in
designing the experiments, accomplishing my goals would have been
difficult at best. Thanks again, Jim.

I would also like to thank Kevin Chase, Steve Boyer, and Brian
Long for their assistance in the fielcl studies. Special 'thanks go to
Dale Mutch fer the pep talks, Frank Roggenbuck for the gardening tips,
and Dennis Cosgrove for the Sports updates. I would also like to
express my gratitude to Jackie Schartzer for typing the thesis and for
all her unselfish assistance. For friendship and timely advice, I
would like to especially thank Karen Renner and Gary Powell. You and
the rest of the weed science crew have made completion of this project

a particularly enjoyable and memorable experience for me.

111'

TABLE OF CONTENTS

LIST OF TABLES ..........................
LIST OF FIGURES .........................
CHAPTER 1: REVIEW OF LITERATURE

INTRODUCTION ........................

Soil Suitability .....................
Tillage Requirements ...................
Herbicide Use ......................
Advantages and Disadvantages ...............
Methods of Weed Control .................

LITERATURE CITED ......................
CHAPTER 2: HERBICIDES FOR RIDGE TILL-PLANTED FIELD CROPS
ABSTRACT ..........................
INTRODUCTION ........................
MATERIALS AND METHODS ....................

General Experimental Procedures .............
l984 ...........................
1985 ...........................

RESULTS AND DISCUSSION ...................

1984 ...........................
I985 ...........................

LITERATURE CITED ......................

CHAPTER 3: CROP YIELD AND WEED CONTROL AS INFLUENCED BY

HERBICIDE APPLICATION AND CULTIVATION

ABSTRACT ..........................
INTRODUCTION ........................
MATERIALS AND METHODS ....................

iv

PAGE

vi

9

29

36

37
58

64

69

PAGE
CHAPTER 3 CONTINUED:

RESULTS AND DISCUSSION ................... 74
LITERATURE CITED ...................... 85
CHAPTER 4: SUMMARY AND CONCLUSIONS ............... 9l
Appendix I ......................... 94
Appendix 2 ......................... 95

LIST OF TABLES
TABLE PAGE

CHAPTER 2: l. Mid-season evaluations of common lambs-
quarters and common ragweed control with
early preplant or preemergence herbicide
treatments in ridge till-planted corn,
1984 .......... . .......... 38

2. Late-season evaluations of common lambs-
quarters and common ragweed control with
preemergence herbicide treatments with
and without early preplant herbicide
treatments in ridge till-planted corn,
l984 ..................... 40

3. Late-season evaluations of common lambs-
quarters and common ragweed control with
preemergence herbicide treatments with
and without early preplant herbicide
treatments in ridge till-planted corn,
l984 ..................... 4l

4. Evaluations of dandelion control with
early preplant, preemergence, and
sequential herbicide treatments in ridge
till-planted corn, l984 . . . ........ 43

5. Early, mid-, and late-season evaluations
of common lambsquarters and common
ragweed control with preemergence
herbicide treatments followed by layby
applications in ridge till-planted
corn, l984 ...... . ........... 44

6. Early- and mid-season evaluations of
common lambsquarters and common
ragweed control with postemergence
herbicide treatments in ridge till-
planted corn, l984 .............. 46

vi

CHAPTER 2 CONTINUED:
TABLE PAGE

7. Mid-season evaluations of common
lambsquarters and common ragweed
control with early preplant
treatments in ridge till-planted
soybeans, l984 ................ 48

8. Mid-season evaluations of common
lambsquarters and common ragweed
control with preemergence herbicide
treatments in ridge till-planted
soybeans, l984 ................ 49

9. Late-season evaluations of common
lambsquarters and common ragweed
control with early preplant and
preemergence herbicide treatments
in ridge till-planted soybeans, l984 ..... Sl

l0. Mid- and late-season evaluations of
common lambsquarters and common
ragweed control with sequential
herbicide applications of an early
preplant application followed by
a preemergence application in ridge
till-planted soybeans, l984 ......... 52

ll. Mid- and late-season evaluations of
common lambsquarters and common
ragweed control with sequential
herbicide applications of a
preemergence application followed
by a layby application in ridge

till-planted soybeans, l984 ......... 54
l2. Ridge till-planted soybean injury

evaluations, l984 .............. 55
l3. Early and mid-season evaluations of

common lambsquarters, common ragweed

control and soybean injury with

postemergence treatments in ridge

till-planted soybeans, l984 ......... 57

14. Mid- and late-season evaluations of
common lambsquarters and dandelion
control and early- and mid-season
soybean injury evaluations with
early preplant or preemergence
herbicide treatments in ridge till-
planted soybeans, l985 ............ 59

vii

CHAPTER 3:

TABLE
I.

2.

PAGE

Preemergence herbicide treatments
for ridge till-planted corn ......... 7O

Preemergence herbicide treatments
for ridge till-planted soybeans ....... 7l

Ridge till-planted corn and soybean

yields as influenced by method of

herbicide application and cultivation,

1985 ..................... 84

viii

CHAPTER 3:

FIGURE

1.

LIST OF FIGURES
PAGE

Common ragweed control in ridge

till-planted corn as influenced

by method of herbicide application

and cultivation, 7/30/85 ............ 75

Common lambsquarters control in

ridge till-planted corn as

influenced by method of herbicide

application and cultivation, 7/30/85 ...... 77

Common ragweed control in ridge

till-planted soybeans as influenced

by method of herbicide application

and cultivation, 8/8/85 ............. 79

Common lambsquarters control in

ridge till-planted soybeans as

influenced by method of herbicide

application and cultivation, 8/8/85 ....... 81

ix

CHAPTER 1
REVIEH OF THE LITERATURE

INTRODUCTION

Early systems of row crOp production on ridges were based on the
bed-farming practices used for the production of cotton, tobacco and
other high-value crOps that indicated several advantages of the
elevated ridge, such as drainage of ridge and low total power
requirement per acre for production (6). Ridges were formed with
either rolling disk bedders or lister-type ridging attachments that
utilized a two-way moldboard plow to build ridges either in the growing
crop <n~ after fall harvest. Generally, adequate ridges were
constructed with this equipment. However, the two-bottom lister was
found to be unsatisfactory since it placed crOp residue in a vertical
plane through the middle of the ridge where the planter runner was to
Operate. The residue interfered with the operation of the planter and
poor stands resulted when seeds were planted in this crap residue (6).
Today, with advancements in planting and cultivating equipment, ridging
is much more successful. Ridges planted nO-till with seeds placed into
a slot created by a coulter and planter unit with disk Openers is
termed ridge planting (46). Usually'this term refers to planting only
one seed row per ridge as is the case for till-planting on ridges.

Till-planting involves the tilling of a strip of soil, usually in the

Old crOp row, to prepare a seedbed for row crOps while leaving a
protective cover of crop residue on, and mixed, in the surface layer
between the crop rows (46). fill-planting may be done on a flat or
ridged soil surface. Seedbed preparation and planting are completed in
the same Operation. Normally, till-planting on ridges occurs on ridges
prepared in the growing crOp or after harvest in the fall (26, 29, 43,
46, 65, 67, 72, 73, 86% If formed at cultivation time, all residues
of the growing crop will remain on the soil surface.

In 1985, the ridge till-plant system increased in acreage by 45%
in the United States, and more than 75% Of that increase occurred
within the Cornbelt and Northern Plains Regions]. There is clearly
much interest in this and other conservation tillage systems and
although research has dealt with the refinement of the ridge till-plant
system, little research has been applied to weed control. The purposes
of studies conducted in the ridge till-plant system were to: a)
evaluate timing of herbicide application and multiple applications for
weed control and crOp tolerance; b) examine the contribution of
herbicide application and cultivation as components Of a total weed
control strategy; and c) examine the effect of various weed control

strategies on crOp yield.

1According to a survey based on data provided by the Soil Conservation

Service in conjunction with the COOperative Extension Service,
Agricultural Stabilization and Conservation Service, Soil and Water
Conservation Districts and Agribusiness. (Executive summary
obtainable from the Conservation Tillage Information Center, 2010
Inwood Drive, Fort Wayne, IN 46815).

Soil Suitability

Research in Michigan (67), Ohio (78, 79), and Indiana (26) has
demonstrated that soil characteristics have a definite influence on
crOp response to tillage systems and has made suggestions for tillage
selection based on certain soil and environmental conditions. Research
has shown that one Of the primary considerations before implementation
of the ridge till-plant system of row crop production is soil
suitability. Soil texture (26, 28, 65, 67, 79), natural soil drainage
(2'6, 29, 67, 79), and surface slope (12, 26, 67) have been determined
to be important factors in the intensive management of crop residue
(6,11,14,15, 25, 42, 43, 51, 60, 86, 88), and bed configuration (1,
9, 70, 86) has been cited as an aid in the reduction of erosion and
maintenance of a warm seedbed.

Medium-textured, well-drained soils have been identified as well
suited to ridge till-planting (26, 28, 65, 67). When ridges are formed
after harvesting in the fall rather than in the growing crOp, the
beneficial effect Of an over-wintering surface residue to prevent
erosion and ridge breakdown may be lost. Galloway eta al. (26)
suggest that till-planting consistently had the best stands Of corn on
sandy loam and loam soils, but Often had poor stands on the poorly
drained, fine-textured soils. They and others (26, 28, 29, 65, 73)
suggested that if ridge height is maintained until planting, the ridge
till-plant system may prove advantageous on these poorly drained, fine-
textured soils due to earlier drying and warming of the seedbed.

In studies onaipoorly'drained soil, Triplett and VanDoren (79)
observed that no-tillage continuous corn yields were significantly less

than continuous corn grown on soil prepared by moldboard plowing in the

fall. However, for tile-drained soil, improving drainage further by
planting on ridges or simply rotating corn with other crOps brought the
nO-till corn yields up to the same level as moldboard plowing. The
study also showed that planting ridges partially substituted for tile
drainage.

The surface slope should be no greater than 3 or 4% for the ridge
till-plant system unless it is contoured (12, 67). If inadequate
residue remains after planting or when planting is not done across the
slope, the erosion control effectiveness drOps greatly (49, 84).
Research in Indiana on very poorly drained soils with less than 2%
slope suggests planting with the slope to prevent ponding in the
furrows(29).

It has been reported that crOp residues left in the furrow
decreases runoff and soil loss as well as the effect Of lepe gradient
(51, 84). According to Moldenhauer (49), some soils require tillage
for most effective erosion reduction. Ridge till-planting allows fOr
this requirement and effectively reduces soil losses by.allowing runoff
to move down the ridges and through the residue accumulated in the
furrow. Research in Delaware has included ridging in the fall followed
by planting a cover crOp of alnixture Of annual ryegrass and hairy
vetch to stabilize the ridge and suppress weed growth (73L. Winter
wheat or rye have been useful as cover crOps especially following
soybeans (72L

While some researchers have emphasized the benefits of a warmer
seedbed due to the ridging configuration, others point to the improved
soil water conservation in the ridge (1, 3, 25, 81). Adams (1)

attributes the better stands and crOp emergence to more available

moisture on the ridge. Amemiya (3) adds that in years of deficient
soil moisture, crOp responses attributable to tillage can be expected.
Fisher and Lane (25) found that a loose spongy ridge could in itself
absorb and hold nearly 0.75 inch Of rainfall.

If compaction was a problem prior to ridging, the system may not
have any immediate benefits. Kapusta and Wolff (36) conducted
experiments on a poorly drained silt loam soil comparing weed control
on ridge-planted versus flat-planted corn. While corn emerged equally
well on ridges as on the flat, growth was slower on the ridges due to
compaction and was reflected in reduced yields, although weed control
was excellent. Stevens et. a1. (73) found less compaction by planting
nO-till corn over the Old soybean row. Corn planted over the row
yielded an average Of 15.5 bushels more per acre than planting between
old rows. Ridging over Old soybean rows, however, did not result in a
significant increase in yield. Reasons cited for failure of ridges to
increase yields were lack of prOper ridge height, use Of well-drained
soils, and failure to make firm ridges well in advance of planting.
Preliminary results in Indiana (47) indicated that ridge till-planting
improved soil structure and resulted in less compaction in comparison

to conventional tillage on a variety Of soils.

Tillage Requirements

Development of a system Of producing corn on ridges is reported
as early as 1938 in Missouri (35). Inadequacy of equipment to build
and maintain ridges led to the abandonment of ridge farming there and
again in Indiana in the late 1940's (29). Lack of satisfactory yield

and weed control were also cited as reasons for its early failure.

Buchele et.arL.(6) listed benefits of reduced soil loss and controlled
water flow on land where other systems failed. With the advent of
good preemergence herbicides and refined equipment in the 1960's, the
concept of row crOp production on ridges gained acceptance in areas of
the Western Corn Belt (29).

Today, the ridge till-plant system has evolved to include
generally/no more than three'tillage Operations in one year (29, 43,
65, 67, 86L Typically the till-plant method involves preparation of
a seedbed for row crOps by scalping the area in the Old crOp row and
leaving a protective cover of crOp residue on, and mixed, in the furrow
between the crop rows. A wide sweep or row-cleaning disks ahead of the
planting unit facilitates scalping of 2-3 inches of the ridges (26, 44,
67), and residues are moved to the furrows. Cultivation during the
growing season may be necessary to control weeds and condition residues
in the furrows for more rapid decomposition (67). Burnside and Wicks
(8) found that cultivation was necessary on soils with high silt
content due to crusting. Soil crusting tends to be less of a problem
on ridges due to the residues in the furrow and lack of standing water
on ridges (67). A ridge-building cultivation in the growing map or
after harvest is a requirement of this system to maintain a ridge for
next year's crop (26, 29, 43, 65, 67, 72, 73, 86).

If the previous year's crOp was corn, planting into the old corn
stubble may be a problem. Variations Of dealing with excessive stubble
on the ridge include chOpping the stalks (25, 43, 47, 55, 68) or
lightly disking the ridge crest prior to planting (11, 25, 43, 55,
68). Wittmuss et. al. (86) reported more even distribution of residues

and less clogging Of machinery in fields where corn stalks were cut.

Regehr (65) mentions two other variations of ridge preparation before
planting. One variation is rotary strip-tillage where the tOps of Old
ridges are rotO-tilled to destroy weeds and prepare the seedbed. The
other variation is to chisel plow the corn stalks and build ridges in
the fall. Wittmuss et. a1. (86) suggests that preplant tillage be
kept to a minimum to conserve soil moisture.

Although preplant cultivation is another trip over the field with
associated labor and fuel costs, it may be a better Option than
preplant disking. Disking breaks down the ridge, possibly to a point
where planted seed may no longer be planted in a warmer, dryer
environment for Optimal germination and emergence (11). Fisher and
Lane (25) reported soil crusting in disked rows after heavy rainfall,
while till-planted rows did not crust.

Four to 6 inches (13, 26), 6-8 inches (44, 73), 7-9 inches (67),
and 8-10 inches;(5) are the suggested heights for ridges built with
ridge-building cultivators. Where residues are light and soils are not
fine-textured, a rolling cultivator may be adequate to build the ridge
(26, 29, 65L. Nebraska research suggests that ridges be formed and
kept as high as possible (43). Ridge till-planting is suited to row
crOps planted in row spacings of 30 inches or more (55, 65, 67).
Research in Nebraska has shown that under dryland conditions, 30 inch
rows have led to greater weed control in the till-plant system compared
to wider row spacings because soil and residues completely cover the

furrows where established weeds may be present (55).

Herbicide Use

In the ridge till-planting system, soil incorporated herbicides do
not appear tO be an Option (11, 29, 55, 68). However, other methods Of
seedbed preparation on the ridge, such as rotary tillage (11) and
preplant disking (55), may allow sufficient incorporation Of herbicides
and effective weed control when a slot-planter is used.

Moomaw (11) listed application of preplant herbicides, preplant
cultivation, or a light disking of ridges ahead of planting as Options
when heavy weed pOpulations occur at planting. Disturbance of the soil
before planting, however, may incorporate weed and volunteer crOp seed
and lead to additional weed management expense (25, 43, 65). Robison
and Wittmuss (68) found that the weed yields in the till-plant system
were significantly reduced by disking in two out of the three years
tested, but crOp yields were only significantly better in one out Of
the three years. Disking prevented early weed competition. However,
the preemergence herbicide treatments gave excellent weed control
without disking deSpite residue cover of 73% (68).

Since shallow tillage for weed control is an Option before and
after planting in the ridge till—plant system, reliance on herbicides
may not be as great as it is for other minimum tillage systems (12, 54,
55, 65, 67). If insufficient residues exist in the furrow to help
suppress weeds or delayed planting allows weeds to attain good size
before the till-plant operation, tank mixes of herbicides with a
burndown component is an Option (11, 29, 55, 63, 65). If planting is
attempted through tall weed growth, problems may arise along the
cutting edge Of the planter sweep where some broadleaf weeds may not be

uprooted (11).

Advantages and Disadvantages

Wicks and Somerhalder (82) found fewer weed seeds in the row after
seedbed preparation with till-planting as compared to a conventional
system. Volunteer corn also was effectively removed from the row to
furrow where it was later controlled by cultivation (82, 86, 89).
Others (7, 33, 81) have reported lower weed pOpulations, particularly
annual grasses, in the ridge till-plant system compared to other
conventional and conservation tillage practices.

Perennial weeds can become a problem in the till-plant system due
to lack Of deep tillage (29, 55). This theme is addressed throughout
the literature on tillage technologies (2, 30, 64, 80, 83), and others
(29, 80) suggest that reduced tillage systems should not be used where
perennial weed problems already exist.

While greater herbicidermanagement may be required for certain
weed problems (12, 55) and timing of tillage Operations are critical
for effective weed control, the ridge till-plant system requires less
labor than conventional and other reduced tillage systems (6, 11, 13,
16, 67, 86). Other than nO-tillage, the ridge till-plant system uses
less fuel (13, 43, 55, 67, 87). According to Wittmuss et. a1. (86),
in a tillage comparison between conventional and ridge till-planting,
tillage costs were reduced 63%. In cost summaries, inputs for the
till-plant system were below all 'tillage systems compared except no-
till systems where input cost was comparable (16, 87). Jose (11) found
that the ridge till-plant system was the least cost system due to less
equipment expense and lower herbicide expense. Although the nO-till
system was found to be energy efficient, higher chemical costs tended

to outweigh those cost savings. Wittmuss et.erl.(87) found that

IO

output/input ratios for till-planting in corn and sorghum were among
the highest Obtained in comparison to other systems of crap production.

Early studies by Buchele et.arl.(6) indicated that farming on
ridges produced yields equal to those Obtained under conventional
tillage. In Nebraska, Wittmuss et. al. (86) Obtained an average yield
of two bushels per acre Of corn greater with the till-plant system than
conventional 1y tilled plots compared over fifteen locations. Olson and
Schoeberl (60) conducted yield trials in four tillage systems including
till-planting and conventional systems and found no significant
difference in corn yield in any year or in 4-year averages. In long-
term tillage experiments in Indiana, till-planting gave higher yields
on well-drained soils and lower yields on poorly drained soils as
compared to conventional moldboard plow tillage (28, 29). Mannering
and Griffith (47) found no differences in four-year averages of yield
of continuous corn planted into plots that were either moldboard plowed
or till-planted on ridges. Research in Nebraska (43) indicated no
significant difference in maximum yields in long-term studies comparing
conventional tillage and till-planting. Mock and Erbach (48) reported
reduced growth and productivity Of early planted corn grown on till-
planted and slot-planted ridges as compared to corn grown on moldboard
plowed ground. They attributed reduced stands to nonuniformity of
planter seeding depth and lower soil temperatures. However, in one of
the two years of their study, til 1-planted ridges attained a higher
yield and comparable soil temperature compared to a moldboard plow

system, though neither figure was significantly different.

ll

Observed benefitscnithe ridge till-plant system also include
prevention of soil compaction in the row due to restricted traffic in
the furrows (11, 43, 67, 73), a drier and warmer seedbed (6, 9, 11,
12, 13, 65, 67, 70, 86), more rapid emergence on the ridge (44, 81),
and reduced runoff and soil loss due to the ridging tillagee(4, 6, 12,
13, 14, 15, 32, 34, 42, 43, 49, 50, 60, 84, 88). However, in studies
of 4 tillage systems, Olson and Schoeberl (60) indicated that the
average soil temperature at seed depth by mid-June did not differ
greatly from year to year or from tillage system to tillage system and
that final yield was not consistently related to early soil temperature
or to early growth of corn seedlings.

Lack of sufficient residue to maintain erosion control on ridges
following soybean or navy bean harvest has been cited as a potential
problem (67). Adaptation Of the system to non-row crOps for economic
production may also be a shortcoming of the ridge till-plant system.
Drilling wheat or soybeans into a ridge configuration is physically
impossible. Cultivation is not possible in narrow row soybeans (61L
Even if ridge-building cultivation occurred after harvest in the fall,
it would eliminate the advantage of increased surface residues to

control erosion that narrow row soybeans might otherwise create» Cover

crops may be seeded broadcast when erosion is a problem (67, 73).

Methods Of Weed Control

Due to the scalping of the ridge at planting and the Option of
cultivation during the growing season, banding of herbicide on the
cleanly tilled ridge and reliance on cultivation to control weeds

between the rows appears to be the most economical use of herbicides in

12

this system. When weeds are not present at planting, a banded
application Of preemergence herbicides with subsequent cultivation as
necessary is sufficient (11, 29, 54, 55, 65). In this system, banding
of herbicides over the row may be more necessary with soybeans or milo
than corn (43).

Moomaw and Robison (57, 58, 59) found in three separate
experiments on soybeans, corn and sorghum grown on flat-tilled land,
that banded applications of preemergence herbicides required one
supplementary cultivation to control weeds and maintain crOp yield as
effectively as broadcast treatments. They also found that broadcast
treatments without mechanical tillage yielded as well as the handweeded
check in two out Of three years for soybeans and both yearslof'a two
year study for sorghum. Broadcast treated corn without cultivation
produced significantly less grain than the handweeded check both years
of a two year experiment. They suggested that insufficient rainfall
reduced herbicide performance and contributed to significant yield
reduction in those years when herbicide treatments were not followed by
cultivation.

Research in Indiana (29) indicates that broadcast application Of
preemergence herbicides on ridges should be applied at rates 10-20%
higher than conventional tillage rates due to cloddiness and residues
in the furrows. Due to this undisturbed portion of the field, the ridge
till-plant system draws many Of the weed control strategies from the
nO-till system of crap production. Increased rates for banded
applications Of herbicides is not necessary since the rows are clean
tilled by the till-planter. Robison and Wittmuss (68) evaluated ten
different preemergence herbicide treatments and one postemergence

treatment for three years on till-planted ridges that were disked or

l3

nondisked prior to planting. The broadcast treatments were all
effective in controlling weeds, but increased control was Obtained on
disked ground where a 35% average reduction in surface residue
decreased interception of herbicides. A shallow preplant disking may
be a substitute for herbicides in controlling emerged weeds (55).

Moomaw and Martin (54) investigated weed control in till-planted
and slot-planted corn on ridges and found that till-planting was less
dependent on herbicides due to increased surface tillage. Maximum corn
yield was achieved in the till-plant system with banded applications Of
preemergence herbicides followed by one cultivation.

Cultivation for purposes other than weed control or forming the
ridge may waste energy and cause loss of soil moisture (43L. It is
generally agreed that the number of cultivations required in the till-
plant system is dependent on level Of weed infestation and herbicide
effectiveness. Moomaw (52) and Moomaw and Martin (54) found that
mechanical cultivation alone gave weed control not significantly
different than any of the cultivation treatments including herbicides
in till-planted corn. Regehr (65) suggests that two cultivations are
usual 1y needed if herbicides are banded on the ridge. Peters et. al .
(62) found that two cultivations gave significantly greater soybean
yield and increased weed control than one cultivation where weeds were
not sufficiently controlled by herbicides. Burnside and Wicks (8)
found that the combination of cultivation and herbicides gave more
dependable weed control in sorghum than either method used alone. But
with effective treatments Of atrazine, there was no significant
difference in sorghum yield between plots cultivated 0, 1, 2, or 3

times. Gebhardt (27) found that in a conventionally til led field, a

l4

combination of cultivation and preemergence herbicide treatments was
necessary for improved weed control and soybean yield. Moomaw and
Martin (54) found that slot planted corn on ridges benefited from two
cultivations rather than one in terms Of crOp yield and weed control.
Studies have shown that tillage has little influence on crOp yield in
the absence of weeds (31, 77). Swanson and Jacobson (76) found that if
sufficient moisture and plant nutrients were supplied to corn,
cultivation may not be needed to eliminate all weeds. Corn yields did
not suffer from lack of cultivation, and soil structure deteriorated
least with one cultivation compared to three.

In Nebraska, the approach used to control weeds on till-planted
ridges has been to apply standard soil-applied, preemergence herbicides
at planting and to deal with emerging weeds as they occur. If weeds,
such as winter annuals, germinate prior to the planting Operation, they
are controlled with selective or nonselective postemergence herbicides
or light tillage (11, 54, 55). Moomaw and Martin (54) found that if
slot-planting was substituted for till-planting on the ridge, a
preplant application of 2,4-D was essential for emerging broadleaf weed
control and maintaining comparable corn yield between weed control
methods used in the two planting systems.

In nO-tillage and reduced tillage systems, early preplant
applications of residual herbicides have been tested as an approach to
controlling weeds prior to planting and as an aid to early season
control (10, 17, 18, 19, 20, 21, 22, 23, 24, 36, 37, 38, 39, 40, 41,
45, 65, 66, 69, 74, 75). In Iowa, Fawcett et. a1. (17) found over ten
locations that early preplant treatments Of residual herbicides in nO-

till corn gave comparable weed control to planting-time treatments

15

consisting Of residual and nonselective postemergence herbicides
despite the heavy rainfall encountered. In subsequent years testing of
residual early preplant applications at different locations in no-till
corn, results showed that early preplant treatments generally provided
equal or greater weed control than preemergence treatments (19, 20, 22,
24). Early preplant treatments generally provided 90% giant foxtail
control (19, 20, 22) except several treatments where cyanazine was used
alone(20).

The primary Objective Of applying early preplant treatments is to
prevent weed germination during planting and early crop growth. Risk
of herbicide failure due to dry weather after application is reduced,
since the probability Of receiving rainfall after herbicide application
and prior to weed germination is increased. However, Lueschen and
Hoverstad (45) reported failure of sequential applications, including
an early preplant application, to provide adequate control on ridge
till-planted corn due to lack of adequate rainfall. When frequent and
heavy rainfall occurred before early preplant applications and near
planting, studies conducted by Fawcett et. a1. (18) indicated that
early preplant applications on nO-till soybeans did not provide weed
control superior to preemergence treatments.

Fawcett et. al. (17, 18, 19) suggested that early preplant
applications of residual herbicides usually eliminate the need for a
nonselective postemergence herbicide in any planting-time application.
Stougaard et.arl.(75) found that fall and early preplant applications,
including only residual herbicides, eliminated the need for
nonselective herbicides at planting. However, Staniforth and Lovely

(71) found that applications of alachlor, chloramben, and metribuzin,

16
prior to weed emergence and alone and in various combinations, seldom
eliminated the need for a nonselective burndown herbicide.

Although season-long weed control with early preplant applications
of residual herbicides has been reported in the ridge till-plant (36),
reduced tillage (40), and no-tillage systems (17, 40, 75), insufficient
season-long control with early preplant treatments has also been
reported (18, 19, 21, 39, 41, 45, 74, 75). Krausz and Kapusta (41)
found that split applications involving an early preplant application
gave the most complete control of broadleaf weeds in nO-till
soybeans. Fawcett et. a1. (17, 18, 19, 20, 22) found over years and
locations in Iowa that split applications involving both early preplant
application and preemergence application improve consistency of weed
control in no-tillage corn and soybeans by compensating for soil
disturbance caused by the planter and providing longer herbicide
persistence. This has special implications for ridge till-planting
where wide sweeps or row-cleaning discs will remove considerably more
herbicide treated soil from the row than nO-till planting.

Cantwell and McGlamery (10) found essentially no differences in
weed control between early preplant and sequential applications in no-
till corn, except that cyanazine control led vel vetleaf more effectively
with split applications than with early preplant applications alone.
Fawcett et. al . (24) found that split application Of cyanazine in nO-
till was more effective in controlling fall panicum in nO-till corn
than a single early preplant application. Krausz and Kapusta (40)
reported poor fall panicum control with early preplant applications of
triazine herbicides. Roskamp (69) and Fawcett et. al. (20) reported
reduced giant foxtail control in no-tillage systems with cyanazine

applied early preplant.

17

Another approach to controlling weeds at midseason in the no-
tillage system has been to apply postemergence herbicides or to
cultivate (19, 21, 23, 66). Fawcett et. a1. (21) found in a nO-till
soybean study that due to heavy rainfall during the early growing
season, treatments including supplemental postemergence applications,
generally gave better weed control than treatments relying on early
preplant or preemergence applications alone. Many of the soil applied
treatments provided satisfactory late season weed control 'flrllowing a
row cultivation.

In the ridge till-plant system, when cultivation to rebuild the
ridge is done in the growing crop, applications Of residual herbicides
at this time may extend weed control to the end Of the season. Moomaw
and Martin (53) and Moomaw et. a1. (56) found that layby applications
were effective in controlling late germinating weeds in irrigated corn
and extended weed control through the end of the growing season. Weeds
that did emerge in layby herbicide treated areas remained small and

annual grass seed production was effectively reduced.

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18

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20

Fawcett, R. S., L. G. Brenneman, J. L. Creswe11,. and G. B.
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Fawcett, R. S., M. D. K. Owen, and P. C. Kassel. 1983. Early
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weed control in no-till corn at the Curtiss Farm, Ames, Iowa,
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preplant, preemergence and postemergence applied herbicides for
weed control in nO-till soybeans at the Curtiss Farm, Ames, Iowa,
1984. Res. Rep. North Cent. Weed Cont. Conf. 41:84-88.

Fawcett, R. S., M. D. K. Owen, J. F. Lux, R. G. Hartzler, D.
Studt, K. Connelly, K. Ross. 1984. Evaluation of early preplant,
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Fawcett, R. S., M. D. K. Owen, J. F. Lux, R. G. Hartzler, D.
Studt, K. Connelly, and K. Ross. 1984. Evaluation Of early
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24.

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21

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Fisher, W. F., and D. E. Lane. 1973. Till-planting. Proc. Cons.
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Galloway, H. M., D. R. Griffith, and J. V. Mannering. 1981.
Adaptability Of various tillage-planting systems to Indiana
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Gebhardt, M. R. 1981. Preemergence herbicides and culti vations

for soybeans (Glycine max). Weed Sci. 29(2):165-168.

 

Griffith, D. R., J. V. Mannering, H. M. Galloway, S. 0. Parsons,
and C. B. Richey. 1973. Effect of eight tillage-planting systems
on soil temperature, percent stand, plant growth, and yield of
corn on five Indiana soils. Agron. J. 65:321-326.

Griffith, D. R., J. V. Mannering, D. B. Mengel , S. 0. Parsons, T.
T. Bauman, D. H. Scott, F. T. Turpin, and D. H. Doster. 1982. A
guide to till-planting for corn and soybeans in Indiana. Ext.
Bull. 10-148, Purdue Univ. Cooperative Extension Service.
Griffith, D. R., J. R. Mannering, and W. C. Moldenhauer. 1977.
Conservation tillage in the eastern cornbelt. J. Soil and Water
Cons. 32(1):20-28.

Hinesly, T. 0., E. L. Knake, and R. D. Seif. 1967. Herbicide
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22

Johnson, H. P., J. L. Baker, W. D. Shrader, and J. M. Laflen.
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Johnson, M. D., D. L. Wyse, and W. E. Lueschen. 1984. The
influence of herbicide formulation on weed control in reduced
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better environment. Proc. Cons. Tillage Conf. Soil Cons. Soc. Am.
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Jones, M. M., and R. P. Beasley. 1945. Corn tillage studies on
Putnam silt loam. Mo. Agr. Exp. Sta. Bull. 475.

Kapusta, G., and R. L. Wolff. 1985. Weed control in ridge vs.
flat-plant corn and soybeans, 1985. Res. Rep. North Cent. Weed
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Kells, J. J. 1984. Early preplant herbicide applications in no-
till corn and soybeans. Proc. North Cent. Weed Cont. Conf. 39:42.
Knake, E. L., L. E. Paul, and M. S. Orfanedes. 1985. Early
preplant treatments for corn planted nO-till in soybean stubble.
Res. Rep. North Cent. Weed Cont. Conf. 42:294.

Krausz, R. F., and G. Kapusta.1985. Corn no-till early preplant
herbicide study, Bel leville, 1985. Res. Rep. North Cent. Weed
Cont. Conf. 42:173.

Krausz, R. F., and G. Kapusta. 1985. Corn no-till and reduced-
till early preplant herbicide study, 1985. Res. Rep. North Cent.
Weed Cont. Conf. 42:286-287.

41.

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23

Krausz, R. F., and G. Kapusta. 1985. Soybean nO-till early
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P. Johnson. 1978. Soil and water loss from conservation tillage
systems. Trans. Amer. Soc. Agr. Eng. 21:881-885.

Lane,[L E”.and R.Gaddis.Conservation production systems for
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Extension Service.

Lueschen, W. E., and T. R. Hoverstad. 1984. The effects of
residual trifluralin and tillage on corn performance at Waseca,
MN, in 1984. Res. Rep. North Cent. Weed Cont. Conf. 41:216-217.
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ridge-tilled corn at Waseca, MN, in 1985. Res. Rep. North Cent.
Weed Cont. Conf. 42:290-291.

Mannering,rL V.,and C.R.Fenster.1983. Whatis conservation
tillage? J. Soil and Water Cons. 38(3):141-143.

Mannering, J. V., and D. R. Griffith. Tillage research progress
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County (Indiana) Soil and Water Cons. District.

Mock, J. J., and D. C. Erbach. 1977. Influence of conservation-
tillage environments on growth and productivity of corn. Agron.
J. 69(3):337-340.

Moldenhauer, W. C. 1985. A comparison of conservation tillage
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52.

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58.

59.

24

Moldenhauer, W. C., and M. Amemiya. 1969. Tillage practices for
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Moomaw, R. S. 1972. Progress Report, Weed Control Research.
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25

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26

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27

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86.

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28

Wittmuss, H. D., D. E. Lane, and B. R. Somerhalder. 1971. Strip
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Proc. Cons. Tillage Conf. Soil Cons. Soc. Am. pp.5-12.

 

 

CHAPTER 2
HERBICIDES FOR RIDGE TILL-PLANTED FIELD CROPS

ABSTRACT

Field studies were conducted in corn (Zea mays L.) and soybeans

(Glycine max (L.) Merr.) grown under the ridge till-plant system to

 

evaluate weed control and crOp tolerance for various herbicide programs
and application timings. Only one cultivation followed planting to
reform ridges. Preemergence herbicide applications, preceded by an
early preplant application or followed by a layby application, provided
the most consistent control of annual weeds and caused little or no
crop injury.

Prior to cultivation, which occurred approximately 7 weeks after

planting, control of common lambsquarter (Chenopodium album L.) and

 

common ragweed (Ambrosia artemisiifolia L.) in corn was visually

 

evaluated at 90% or greater for all early preplant treatments and
provided satisfactory control of these weed species throughout the
season. All preemergence treatments in corn also provided satisfactory
season-long control Of common lambsquarters and common ragweed.

In soybeans, in 1984, early preplant applications of alachlor (2-
chlorO-N-(2,6-diethylphenyl)-N—(methoxymethyl) acetamide) at 3.36 kg/ha
or oryzalin (4-(dipropylaminO)-3,5-dinitrobenzenesulfonamide) at 1.68

kg/ha in combination with metribuzin (4-amino-6-(1,1-dimethylethyl)-3-

29

3O
(methylthiO)-1,2,4-triazin-5(4H)-one) at 0.56 kg/ha provided greater
than 93% control of common lambsquarters and common ragweed prior to
cultivation. Weed control for all early preplant treatments decreased
by the late-season evaluation.Preemergence applications of alachlor at
3.36 kg/ha in combination with metribuzin at 0.56 kg/ha or linuron (N_'.-
(3,4-dichlor0phenyl)-N-methoxy-N-methylurea) at.(L84 kg/ha provided 90%
or greater control (rf both weed species throughout the season.
However, “11985, early preplant applications hisoybeans provided
equal or greater weed control and crop tolerance than preemergence
applications of the same herbicides, and generally'provided season-long
control of the weeds evaluated. Rainfall data indicated that much less
rainfall occurred in 1985 at planting and was not adequate for
activation of the residual herbicide component of the preemergence

treatments.

INTRODUCTION

With the availability of a wider variety of herbicides for corn
and soybeans, conservation tillage systems have become feasible
alternatives to conventional tillage systems. The ridge til'L-plant
system is unique in that it requires a scalping of an established ridge
crest at planting and at least one cultivation to rebuild the ridge for
the subsequent year's crop, while maintaining surface residues for
erosion control. The farmer must develOp weed control strategies
around these requirements in the growing crop.

Much Of the research involving till-planting on ridges has
centered around erosion control and refinement of the tillage system to
maintain Observed benefits and ultimately, to attain yields comparable
with other tillage systems. Only'recently'have refinementsirlweed
control research been applied to the ridge till-plant method of row
crop production.

Ideally; as in no-till, the soil and surface residues are left
undisturbed much of the time under the ridge till-plant system,
particularly between crOps. If weeds are anticipated before planting,
one approach has been to apply residual herbicides Often several weeks
before planting, to prevent weeds from germinating. If coordinated
with rainfall and properly applied, early preplant treatments have been
shown to be an excellent means Of controlling weeds in nO-tillage and

ridge til l-plant systems. Kapusta and Wolff (7) reported excellent

31

32

annual weed control in ridge tilled corn and soybeans with early
preplant applications. Lueschen and Hoverstad (8) found no advantage
to applying early preplant herbicide treatments in ridge till-planted
corn when weed densities were high and insufficient rainfall occurred
fiollowing early preplant applications. Fawcett et. al. (2, 3, 4)
suggested that early preplant applications of residual herbicides in
nO-till reduces the risk of herbicide failure due to dry weather.

In Nebraska, early germinating weeds on ridges are controlled with
selective or non-selective herbicides or light tillage before or at
planting (1, 10, 11L Staniforth and Lovely (13) found that early
preplant applications of alachlor, chloramben, or metribuzin, alone or
in combination, seldom eliminated the need for a burndown herbicide in
nO-till soybeans. However, Stougaard et. al. (15) found that fall or
early preplant applications of cyanazine or cyanazine plus oryzalin
prevented weeds from becoming established before planting and caused no
injury to no-till soybeans.

Fawcett et. a1. (2, 4, 5) found that split applications involving
both early preplant application and preemergence application improved
the consistency of weed control 'hi no-till. The preemergence
application was made to compensate for soil disturbance at planting and
extend residual weed control. There was considerably more soil
disturbance in till-planting on the ridge than nO-till planting where
seed was planted into a slot. This does not necessarily translate into
increased use of herbicide at planting. Wicks and Somerhalder (16)
found that the till-planter left only 30% as many weed seeds in the
corn row as when the seedbed was prepared by plowing, disking, and

harrowing. Due to the removal of residues from the row, the soil

33

interception of herbicides in the row at planting should be comparable
to conventional tillage systems. However, research in Indiana (6)
suggested that broadcast application of preemergence herbicide rates on
ridges should be increased by 10 to 20% compared with rates used in
conventional tillage due to the cloddiness and residue in the furrow.

Whenever cultivation is done, new weed seed has the Opportunity to
germinate. Stobbe (14) reported that the majority of weeds imported to
North America from EurOpe require cultivation in order to germinate.
Since ridge-building cultivation moves soil into the row and inverts
herbicide-treated soil, a supplemental layby application of herbicides
may be useful in maintaining season-long weed control and reducing weed
seed production. Moomaw and Martin (9) and Moomaw et. a1. (12) found
layby applications to be effective in control ling late germinating
weeds in irrigated corn and in extending weed control to full season.
Weeds that did emerge after layby applications remained small and
annual grass seed production was reduced with various treatments.

The purpose Of the following studies in corn and soybeans was to:
a) examine strategies for weed control with herbicides in the ridge
till-plant system and b) evaluate timing of application and multiple

applications for weed control and crap safety.

MATERIALS AND METHODS

General Experimental Procedures

The experiments were conducted on established ridges built the
previous year at North Star in Gratiot County, Michigan. All studies
were conducted on a Parkhill soil series. In both corn (133m L.)

and soybean (Glycine max U") MerrJ studies, the plots were 3A) m

 

wide (4 rows) by 15.2 m long. The crOps were planted in 76 cm rows.
Soil applied herbicides were applied with a tractor mounted compressed
air sprayer. Early preplant, preemergence and sequential applications
of these treatments were applied in 215 L/ha water carrier at 206 kPa
and included crop Oil concentrate (COC)1 (2.34 L/ha) or paraquat (0.56
kg/ha)-I-X-772 UL25%‘v/v)irlthe initial application to facilitate
burndown of existing weeds. Postemergence applications were made with
a C02 backpack sprayer at 343 kPa. Postemergence broadcast treatments
were applied in 234 L/ha, and post-directed treatments, including layby
applications, were applied in 187 L/ha water carrier using drop

nozzles.

1Herbimax - Registered trademark of Union Carbide Corp.,
manufactured for: Loveland Industries, Inc., Loveland, Colorado 80537
(83% light paraffinic distillate, odorless aliphatic petroleum
solvent, 17% mono- and diesters of omega hydroxpoly oxyethylene).

2X-77 - Registered trademark of Chevron Chemical Company, San

Francisco, CA 94120 (functioning agents: alkylarylpolyethylene,
glycols, free fatty acids, and isoprOpanOl).

34

35

Herbicide treatments were evaluated visually for weed control and
crOp tolerance based on the untreated check. Each study was arranged
in a randomized complete block design with 4 replications. Analyses Of
variance were computed on all data. Differences among treatments were
tested with Duncan's multiple range test at the 5% level of
significance.

1984. Herbicide combinations were applied to corn and soybeans on
soybean residue and corn residue, respectively. Herbicide treatments
were aimed at providing broad spectrum weed control Of annual weed
species that occurred in the ridge till-plant system while maintaining
crOp tolerance.

Both crOps were till-planted on ridges with a 12-row Hiniker Econ-
O-T'ill3 planter. Corn varieties used were 'Pioneer 3744 and 3747' and
the soybean variety'was'Corsoy 792. The predominant annual weeds in

both studies were common lambsquarters (Chenopodium album L.) and

 

common ragweed (Ambrosia artemisiifolia L.L. Dandelion (Taraxacum

 

officinale Weber in Wiggers) was present throughout the corn experiment

 

and was the only perennial evaluated. Annual grass species were not
evaluated due to lack of uniform and sufficient population.

The corn was planted on May 8. The soil texture was a clay loam
with pH 6.6 and 3.4% organic matter. Early preplant applications were
applied 6 days prior to planting and preemergence applications were
applied 8 days after planting. Other than injection of anhydrous
ammonia on June 9, the ridges were not disturbed after planting until
June 30 when the field was cultivated to rebuild ridges. Postemergence
applications were made 7 days before ridge building on June 21 and

3Manufactured by Hiniker Company, PJL Box 3407, Mankato, Minnesota
56001.

1"..."

36
layby herbicide applications were made 5 days after ridge building on
July 5. All postemergence treatments except atrazine + COC, which was
broadcast over the crOp, were postemergence directed to the base of the
corn stalk.

Soybeans were till-planted on May 18. The soil texture was a clay
loam with pH 6.8 and 4.8% organic matter. The early preplant treatments
in soybeans were applied 16 days before planting and preemergence
applications were made 7 days after planting. The plots were cultivated
once to build ridges on July 3. Postemergence applications were made
before ridge building on June 21 and following cultivation on July 5.
These applications were postemergence directed except fln~treatments
involving acifluorfen and bentazon which were broadcast.

l985. Herbicides were applied either early preplant or
preemergence to soybeans planted into soybean residue with a 4-row
Buffalo All-Flex4 till planter on May 8. ‘The variety planted was
'Corsoy 792 The soil was a clay loam texture with pH 7.3 and 2.7%
organic matter.

The predominant annual weed in the study was common lambsquarters

(ChenOpodium album Lu). Dandelion (Taraxacum officinale Weber in

 

Wiggers) was the predominant perennial present throughout the study.

Late in the season, giant foxtail (Setaria faberi Herrm.) and green

 

foxtail [Setaria viridis (L.) Beauv.] developed as the primary annual

 

grasses in the study.
Early preplant treatments were applied 9 days before planting on
April 29, while preemergence treatments were applied 1 day after

planting on May 9. The ridges were cultivated once on July 24.

4Manufactured by Fleischer Mfg., Box 848, Columbus, NE 68601.

RESULTS AND DISCUSSION

1984. Visual evaluation of weed control in ridge till-planted
corn and soybeans indicates that the use of herbicides in this system
is needed to achieve satisfactory control of weeds. The importance Of
timing Of soil applied herbicide application was less evident in corn
than in soybeans. This may have been due in part to the different time
interval between early preplant applications and planting of the crop.
In the soybean study, this time interval was 16 days, and with corn
only 6 days passed after early preplant treatments before the corn was
planted. In addition, much less rainfall occurred between early
preplant and preemergence applications (May 2-May 16) in corn as
compared to the rainfall occurring in the corresponding period (May 2-
May 25) in soybeans (Appendix 1).

Rainfall data in Appendix 1 shows that early preplant herbicide
treatments (applied May 2) in the corn study did not receive
substantial rainfall until just prior to preemergence applications made
on May 16. This would suggest that early preplant residual herbicides
in corn were not activated adequately until close to the preemergence
timing. Mid-season visual evaluations of common lambsquarters and
common ragweed control, with either early preplant or preemergence
applications of atrazine in combination with alachlor or metolachlor,
were not significantly different (Table 1). Rates used for residual

herbicides in the early preplant treatments were 20 to 30%

37

38

 

 

 

Table l: Mid-season evaluations of common lambsquarters and common
ragweed control with early preplant or preemergence
herbicide treatments in ridge till-planted corn, 1984. ’

Rate
common4 common4
Treatment3 EPP PRE lambsquarters ragweed
---------- kg/ha--------- ------------%---------
alachlor + 3.36 + 2.24 100 a 100 a
atrazine 2.80 + 1.68 99 a 100 a
metolachlor + 2.80 + 2.24 100 a 93 a
atrazine 2.24 + 1.68 100 a 100 a

 

1Means, average of four evaluations, within one column followed by the
same letter are not significantly different at the 5% level using

Duncan's multiple range test.

2Plots received a ridge-building cultivation on 6/30/84.

3Each treatment includes paraquat (0.56 kg/ha) + X-77 (1/4% v/v).

4Evaluations were made on 8/13/84.

39

higher than the preemergence treatments to provide extended control due
to earlier application and removal of a portion of the herbicide
residue from the crOp row by the til 1-planter. Control of these two
weed species was comparable between early preplant.and preemergence
applications in corn and adequate season-long control of the two
species was Obtained for all herbicide treatments tested with either
application timing.

The flowable formulation Of cyanazine was used with a crOp Oil
concentrate and was compared with the atrazine + paraquat + X-77
combination for burndown of existing weeds and for residual weed
control from the early preplant timing. Whether in combination with
alachlor, metolachlor, or alone, the atrazine + paraquat + X-77 tankmix
provided equal or greater control of common ragweed than cyanazine +
COC with these same combinations at the mid-season evaluation (Table
2). Cyanazine (4.48 kg/ha) + COC (2.34 L/ha) alone, at the highest
rate tested, and atrazine + paraquat + X-77 tankmixes alone and in
combination with alachlor or metolachlor gave essentially complete
control of common lambsquarters by the mid-season evaluation (Table 2).
All Of these early preplant treatments provided satisfactory control of
the two annual broadleaf weeds (Table 2).

Preemergence applications were compared to sequential applications
of an early preplant application followed by a preemergence
application. ‘The sequential applications generally provided excellent
season-long control of common lambsquarters and common ragweed (Table
3L. However, when cyanazine was applied at.1.68 kg/ha at the early
preplant timing as part Of a Split triazine herbicide application,

results showed inconsistent control of common lambsquarters by the

40

Table 2: Mid-season evaluations of common lambsquarters and common
ragweed control with early preplant herbicide treatments in
ridge till-planted corn, 1984.1,2

 

 

common4 common4
Treatment3 Rate lambsquarters ragweed
----kg/ha-—-- -------------- % -------------
cyanazine 4.48 100 a 93 a
alachlor +
cyanazine 3.36 + 2.80 91 ab 86 a
metolachlor +
cyanazine 2.80 + 2.80 86 b 95 a
atrazine 2.24 98 ab 96 a
alachlor +
atrazine 3.36 + 2.24 100 a 100 a
metolachlor +
atrazine 2.80 + 2.24 100 a 93 a

 

1Means, average of four evaluations, within one column followed by the
same letter are not significantly different at the 5% level using
Duncan's multiple range test.

zPlots received a ridge-building cultivation on 6/30/84.

3Crop oil concentrate (2.34 L/ha) is included in afll cyanazine
treatments and paraquat (0.56 kg/ha) + X-77 (l/4% v/v) is included in
the atrazine treatments.

4Evaluations were made on 8/13/84.

41

Table 3: Late-season evaluations Of common lambsquarters and common ragweed
control with preemergence herbicide treatments with and without
earl)‘ greplant herbicide treatments in ridge till-planted corn,

9

 

 

 

1984.
Rate

common4 common4

Treatment3 EPP PRE lambsquarters ragweed
............ g-------------

alachlor + atrazine 2.80 + 1.68 100 a 100 a
alachlor + atrazine
+ cyanazine 2.80 + 0.84 + 1.68 99 a 100 a
(cyanazine) + 1.68
alachlor + atrazine 2.80 + 1.68 95 a 100 a
(cyanazine) + 2.80
alachlor + atrazine 2.80 + 1.12 96 a 100 a
(atrazine) + 1.12
alachlor + atrazine 2.80 + 1.12 95 a 95 a
(atrazine) + 1.12
alachlor + cyanazine 2.80 + 1.68 97 a 100 a
(cyanazine) + 1.68
alachlor + cyanazine 2.80 + 1.68 69 b 98 a
metolachlor + atrazine 2.24 + 1.68 97 a 100 a
metolachlor + atrazine
+ cyanazine 2.24 + 0.84 + 1.68 91 ab 100 ab
(atrazine) + 1.12
metolachlor + atrazine 2.24 + 1.12 91 ab 100 ab
(cyanazine) + 1.68
metolachlor + atrazine 2.24 + 1.68 75 ab 93 ab

 

1Means, average of four evaluations, within one column followed by the same
letter are not significantly different at the 5% level using Duncan's
multiple range test.

2Plots received a ridge-building cultivation on 6/30/84.

3Each treatment includes paraquat U156 kg/ha) + X-77 (l/4% v/v) in initial
treatment, except EPP treatment Of cyanazine at 2L80 kg/ha, which
includes C00 (2.34 L/ha).

4Evaluations were made on 10/6/84.

42

late-season evaluation (Table 3). This may have resulted due to the
lack of soil persistence of cyanazine at this rate. Higher rates of
cyanazine tested (2.80 or 4.48 kg/ha) at the early preplant timing,
provided satisfactory control Of common lambsquarters throughout the
season (Tables 2 and 3).

Visual evaluations indicated sequential applications Of an early
preplant application followed by a preemergence application appeared to
provide the greatest control Of dandelion prior to the ridge-building
cultivation (Table 4). However, due to variability within the study,
there were no statistical differences among sequential treatments and
early preplant.and preemergence treatments at P=0.05 according to
Duncan's multiple range test. Dandelion control in this study appeared
to be influenced by the total amount of triazine herbicide applied and
whether or not it was applied sequentially (Table 4).

Sequential treatments of a preemergence application followed by a
layby application of residual herbicides resulted in complete control
Of common lambsquarters and common ragweed throughout the growing
season (Table 5). Data suggest that the addition of paraquat + X-77 at
the preemergence timing, as well as the high rate of layby application
of triazine herbicide may not be required to achieve complete control
of these weeds for the populations present in this study. The addition
of alachlor and metolachlor to layby applications did not improve
control of these weed species (Table 5). Although control of winter
annuals was not evaluated, these species were noticably absent where
layby applications were made. Benefits of the layby applications were

not otherwise Observed in terms of annual weed control in this study.

43

Table 4: Evaluations of dandelion control with early preplant, preemergence,
and segpential herbicide treatments in ridge till-planted corn,

 

 

 

1984.1.
Rate
Treatment3 EPP PRE 6/12/84 6/28/84
--------- kg]ha---------- --------%---------
(cyanazine) 4.48 73 a 75 a
(atrazine) 2.24 63 a 54 a
(alachlor + atrazine) 3.36 + 2.24 59 a 75 a
(alachlor + cyanazine) 3.36 + 2.80 65 a 48 a
(metolachlor + atrazine) 2.80 + 2.24 73 a 25 b
(metolachlor + cyanazine) 2.80 + 2.80 58’a 25 b
(cyanazine) + 1.68
alachlor + atrazine 2.80 + 1.68 100 a 100 a
(cyanazine) + 2.80
alachlor + atrazine 2.80 + 1.12 100 a 100 a
(atrazine) + 1.12
alachlor + atrazine 2.80 + 1.12 93 a 68 a
(cyanazine) + 1.68
alachlor + cyanazine 2.80 + 1.68 100 a 100 a
(atrazine) + 1.12
alachlor + cyanazine 2.80 + 1.68 100 a 100 a
(cyanazine) + 1.68
metolachlor + atrazine 2.24 + 1.68 98 a 100 a
(atrazine) + 1.12
metolachlor + atrazine 2.24 + 1.12 90 a 40 a
alachlor + atrazine 2.80 + 1.68 73 a 33 b
alachlor + atrazine + cyanazine 2.80 + 0.84 + 1.68 93 a 73 a
metolachlor + atrazine 2.24 + 1.68 83 a 50 a
metolachlor + atrazine + cyanazine 2.24 + 0.84 + 1.68 95 a 75 a

 

1Means, average of four replications, within one column followed by the same
letter are not significantly different at the 5% level using Duncan's multiple
range test.

2Piots received a ridge-building cultivation on 6/30/84.
3Each treatment includes paraquat UL56 kg/ha)+-X-77 (l/4% v/v) in initial

treatment, except where cyanazine is applied at 2.80 kg/ha or greater, which
includes COC (2.34 L/ha).

44

Table 5: Early, mid-, and late-season evaluations Of common lambsquarters and common ragweed

control with preemer ence herb
ridge till-planted dOrn, 1984.

(céde treatments followed by layby applications in

 

 

 

Rate
Comnon4 Conmon4
Treatment3 PRE LAYBY Lambsquarters Ragweed
-------------- kg/ha------------- --------:::i-.---------
alachlor + atrazine + cyanazine" + 2.80 + 0.84 + 1.68
(atrazine) 1.12 100 a 100 a
alachlor + atrazine + (atrazine) 2.80 + 1.68 2.24 l00 a 100 a
alachlor + atrazine + cyanazine + 2.80 + 0.84 + 1.68
(atrazine) 2.24 100 a 100 a
metolachlor + atrazine + (atrazine) 2.24 + 1.68 2.24 100 a 100 a
metolachlor + atrazine + cyanazine + 2.24 + 0.84 + 1.68
(atrazine) 2.24 100 a 100 a
alachlor + atrazine + (cyanazine) 2.80 + 1.68 2.24 100 a 100 a
alachlor + atrazine + cyanazine + 2.80 + 0.84 + 1.68
(cyanazine) 2.24 100 a 100 a
metolachlor + atrazine + (cyanazine) 2.24 + 1.68 2.24 100 a 100 a
metolachlor + atrazine + cyanazine + 2.24 + 0.84 + 1.68
(cyanazine) 2.24 100 a 100 a
alachlor + atrazine + cyanazine + 2.24 + 0.84 + 1.68
(alachlor + atrazine) . 1.12 + 1.12 100 a 100 a
metolachlor + atrazine + cyanazine + 2.24 + 0.84 + 1.68
(metolachlor + atrazine) 1.12 + 1.12 100 a 100 a
alachlor + atrazine + cyanazine + 2.24 + 0.84 + 1.68
(alachlor + cyanazine) 1.12 + 2.24 100 a 100 a
metolachlor + atrazine + cyanazine + 2.24 + 0.84 + 1.68
(metolachlor + cyanazine) 1.12 + 2.24 100 a 100 a
metolachlor + atrazine + 2.24 + 1.12
(cyanazine + atrazine) 1.12 + 0.56 100 a 100 a
metolachlor + atrazine + 2.80 + 1.12
(cyanazine + atrazine) 1.12 + 0.56 100 a 100 a
alachlor + atrazine + 2.24 + 1.12
(cyanazine + atrazine) 1.12 + 0.56 100 a 100 a

 

TMeans, average of TOUr evaTuations, within on column fallowed by the sameTTetter are not
significantly different at the 5% level using Duncan's multiple range test.

2Plots received a ridge-building cultivation on 6/30/84.

3Each treatment includes paraquat (0.56 kg/ha) + X-77 (1/4: v/v) iri initial treatment, except

treatment denoted with ’*.

“Evaluations were made on 6/28/84. 8/13/84, and 10/6/84.

45

Postemergence treatments used were generally ineffective in
controlling common lambsquarters (Table 6L. Common lambsquarters had 6
to 10 leaves (5 to 20 cm in height) at postemergence timing. Lack of
adequate coverage Of these weeds with the methods used, in addition to
the advanced stage Of growth, may have caused the poor control Of this
Species. Ametryn + X-77 provided excel lent control of common
lambsquarters initially and at the mid-season evaluation and provided
significantly greater control than the other postemergence treatments
tested (Table 6). Due in part to the ridge-building cultivation on
June 30, mid-season evaluations of all of these treatments indicated
improved control of common lambsquarters (Table 6). However, by the
end Of the season, lack of adequate residual control was evidenced by
late germination of common lambsquarters. Evaluations in early October
for all postemergence treatments were 65% or less for this weed
species.

At the time Of postemergence application, common ragweed had an
average of 6 leaves (7 to 10 cm in height). Initially, ametryn + X-77
showed the greatest potential for postemergence control of common
ragweed as evidenced by the evaluation made one week after
postemergence timing (Table 6). While ametryn + X-77 demonstrated
considerable contact activity with 95% control of common ragweed, the
other treatments provided less than 68% control of this species 1 week
after treatment (Table 6). Control of common ragweed with
postemergence treatments was 94% or greater by the mid-season
evaluation with cyanazine, 2,4-D amine, and ametryn + X-77 at the rates
given in Table 6. Again, the ridge-building cultivation may have

contributed to control of this weed species.

46

Table 6: Early- and mid-season evaluations Of common lambsquarters and
common ragweed control with postemergence herbicide treatments in
ridge till-planted corn, 1984J.2.3

 

 

Common Common
Lambsquarters Ragweed

Treatment4 Rate 5728784‘TBTT3784 6728784—T87T3784

------kg/ha ------------------------ 1 -----------------
atrazine + COC 2.24 + 1 1/2% v/v 33 d 81 b 40 d 81 b
ametryn + x-77 1.79 + 3/41 v/v 88 a 94 a 95 a 98 a
2.4-0 amine 0.56 69 b 71 be 67 b 95 a
cyanazine 2.80 48 c 68 c 53 c 94 a

 

1Means, average of four evaluations, within one column followed by the same
letter are not significantly different at the 5% level using Duncan's
multiple range test.

zPostemergence treatments were applied on 6/21/84.

3Plots received a ridge-building cultivation on 6/30/84.

4Applications were post-directed except atrazine + COC (post-broadcast).

47

Although these postemergence treatments would be expected to
perform the same in any tillage system, given the same environmental
conditions and growth stages of crOp and weeds, the advantage of
selective control with the postemergence directed treatments was
increased due to the greater height differential obtained by producing
the crop on the ridge. Crop injury was evaluated one week after
postemergence applications on June 28. At the June 28 rating, only the
postemergence treatments showed visible injury symptoms (10 to 23%
injury), with ametryn + X-77 being the only treatment to show
significantly greater injury than the soil applied treatments.

In soybeans, in 1984, early preplant or preemergence herbicide
treatments provided satisfactory control of common ragweed prior to
building ridges and through the mid-season evaluation (Tables 7 and
8). However, control of common lambsquarters prior to cultivation on
July 3 varied among early preplant and preemergence treatments. Early
preplant applications of metolachlor with metribuzin at (L56 kg/ha or
linuron at 1.12 kg/ha provided less than 80% control Of common
lambsquarters prior to ridging, while metribuzin atlL56 kg/ha with
alachlor or oryzal in, or metribuzin at 0.84 kg/ha with metolachlor,
provided 96% or greater control of common lambsquarters prior to the
ridge-building cultivation (Table 7). All preemergence treatments
provided essentially complete control of this weed species except
treatments not including linuron or metribuzin as part of the treatment
(Table 8). Over 5 cm of rainfall occurred 2 days prior to preemergence
treatments and another 5 cm fell within a week after application of
these treatments (Appendix 1L Treatments involving chloramben as the

broadleaf component failed to control common lambsquarters prior to the

48

Table 7: Mid-season evaluations of common lambsquarters and common ragweed
contrplzwith early preplant treatments in ridge till-planted soybeans,

 

 

1984.
Common COmmon
Lambsquarters Ragweed
Treatment3 Rate 773784—_—7726784 773784‘TT7726784
--kg/ha-- ----------------- ‘% ----------------------
alachlor + metribuzin 3.36 + 0.56 96 a 92 ab 93 ab 93 ab
alachlor + linuron 3.36 + 1.12 85 a 92 ab 97 a 95 a
metolachlor + metribuzin 2.80 + 0.56 78 a 91 ab 80 b 88 a
metolachlor + linuron 2.80 + 1.12 69 a 77 b 81 b 92 a
metolachlor + metribuzin 2.80 + 0.84 100 a 98 a 95 a 98 a
oryzalin + metribuzin 1.68 + 0.56 100 a 96 ab 98 a 91 a

 

1Means, average Of four evaluations, within one column followed by the same
letter are not significantly different at the 5% level using Duncan‘s multiple
range test.

2Plots received a ridge-building cultivation on 7/3/84 after evaluations on the
same date above were made.

3Each treatment includes coc (2.34 L/ha).

49

Table 8: Mid-season evaluations of common lambsquarters and common ragweed contra? unth
preemergence herbicide treatments in ridge till-planted soybeans, l984. '

 

 

 

 

Common Common
. Lambsquarters Ragweed
Treatment3 Rate 7/3/34 7/26/87 WIN 7/26/84
------ kg/ha--------- -------------------%--------------------
alachlor + chloramben 2.80 + 3.36 46 b 94 a 96 a 95 a
metolachlor + chloramben 2.24 + 3.36 46 b 93 a 96 a 100 a
alachlor + chloramben +
metribuzin 2.80 + 2.24 + 0.42 99 a 99 a 100 a 98 a
alachlor + chloramben +
linuron 2.80 + 2.24 + 0.84 99 a 96 a 100 a 99 a
metolachlor + chloramben
+ metribuzin 2.24 + 2.24 + 0.42 100 a 97 a 97 a 100 a
metolachlor + chloramben
+ linuron 2.24 + 2.24 + 0.84 99 a 99 a 99 a 100 a
alachlor + metribuzin 2.80 + 0.42 99 a 98 a 99 a 99 a
alachlor + linuron 2.80 + 0.84 100 a 98 a 100 a 99 a
metolachlor + metribuzin 2.24 + 0.42 100 a 96 a 98 a 99 a
metolachlor + linuron 2.24 + 0.42 100 a 96 a 99 a 100 a

 

1Means, average of four evaluations, within one column followed by the same letter are not
significantly different at the 5% level using Duncan's multiple range test.

2Plots received a ridge-building cultivation on 7/3/84 after evaluations on the same date
above were made.

3Each treatment includes paraquat (0.56 kg/ha) + X-77 (l/4% v/v) applied preemergence.

50
ridge-building cultivation on July 3 (Table 8). Environmental
conditions were such that a soluble herbicide such as chloramben was
moved below the weed seed germination zone and could not exert its
toxic effects on the common lambsquarters present.

The ridge-building cultivation considerably improved control of
common lambsquarters where previously the early preplant or
preemergence treatments did not provide adequate control (Tables 7 and
8). Twenty-three days after the cultivation, the early preplant
treatment of metolachlor + linuron + COC provided only 77% control of
common lambsquarters while all other early preplant and preemergence
treatments provided 91%.Or greater control of this species. At the
same evaluation, early preplant and preemergence treatments provided
satisfactory control of common ragweed (Tables 7 and 8).

By the late-season evaluation, only an early preplant treatment of
oryzal in + metribuzin + COC (1.68 kg/ha + 0.56 kg/ha + 2.34 L/ha), and
preemergence treatments of alachlor + paraquat + X-77 (2.80 kg/ha +
0.56 kg/ha + 1/4% v/v) with metri buzin (0.42 kg/ha) or linuron (0.84
kg/ha) provided 90% or greater control of common lambsquarters (Table
9L Visual evaluations indicated that preemergence treatments provided
greater control Of common ragweed than the early preplant treatments at
the late-season evaluation. However, due to variability within the
study, there were no statistical difference between the two treatment
timings (Table 9). When preemergence applications of chloramben with
alachlor or metolachlor followed early preplant applications of
linuron or cyanazine, the treatments resulted in 90% or greater control
of both weeds throughout the season (Table 10). Sequential

applications of a preemergence application and a layby application

51

Table 9: Late-season evaluations of common lambsquarters and common ragweed control
with early preplant and iweemergence herbicide treatments in ridge till-
planted soybeans, 1984.'

 

 

 

Rate v
Common Common 4
Treatment3 EPP PRE Lambsquarters4 Ragweed
kg/ha %

alachlor + metribuzin 3.36 + 0.56 84 ab 84 a
alachlor + linuron 3.36 + 1.12 70 ab 71 a
metolachlor + metribuzin 2.80 + 0.56 74 ab 65 a
metolachlor + linuron 2.80 + 1.12 53 b 61 a
metolachlor + metribuzin 2.80 + 0.84 81 ab 83 a
oryzalin + metribuzin 1.68 + 0.56 98 a 80 a
alachlor + chloramben 2.80 + 3.36 68 ab 93 a
metolachlor + chloramben 2.24 + 3.36 65 ab 90 a
alachlor + chloramben +

metribuzin 2.80 + 2.24 + 0.42 75 ab 90 a
alachlor + chloramben +

linuron 2.80 + 2.24 + 0.84 75 ab 86 a
metolachlor + chloramben +

metribuzin 2.24 + 2.24 + 0.42 87 ab 94 a
metolachlor + chloramben +

linuron 2.24 + 2.24 + 0.84 74 ab 96 a
alachlor + metribuzin 2.80 + 0.42 93 ab 100 a
alachlor + linuron 2.80 + 0.84 90 ab 94 a
metolachlor + metribuzin 2.24 + 0.42 65 ab 99 a
metolachlor + linuron 2.24 + 0.42 85 ab 97 a

 

1Means, average of four evaluations, within one column followed by the same letter
are not significantly different at the 5% level using Duncan's multiple range test.

2Plots received a ridge-building cultivation on 7/3/84.

3EPP treatments include COC (2.34 L/ha) and PRE treatments include paraquat (0.56
kg/ha) + X-77 (1/4% v/v).

4Evaluations were made on 10/11/84.

52

Table 10: 1Hd- and late-season evaluations of common lambsquarters and common
ragweed control with sequential herbicide applications of an early

preplant application fo
planted SOybeans, l984.

llfwed by a preemergence application in ridge till-

 

 

 

 

Common Common
Rate Lambsquarters Ragweed
Treatmenta m PRE 7—T—T‘Tr7/3/a o/ /3 7/3/84 10711/84
.......... z------- ------------------z-------------------
(metribuzin) + 0.56
chloramben + alachlor 2.24 + 2.80 100 a 75 a 100 a 75 a
(linuron) + 1.12
chloramben + alachlor 2.24 + 2.80 100 a 93 a 100 a 99 a
(metribuzin) + 0.56
chloramben + metolachlor 2.24 + 2.24 100 a 85 a 100 a 92 a
(linuron) + 1.12
chloramben + metolachlor 2.24 + 2.24 100 a 95 a 99 a 90 a
(cyanazine) + 2,24
chloramben + metolachlor 2.24 + 2.24 99 a 93 a 99 a 90 a

 

1Means, average Of four evaluations, within one column followed by the same letter
are not significantly different at the 5% level using Duncams multiple range test.

2Plots received a ridge-building cultivation on 7/3/84 after evaluations on the same

date above were made.

3Each treatment includes COC (2.34 L/ha) with EPP treatment.

53

provided essentially complete control of both weed species throughout
the season (Table 11). Under environmental conditions that produced
excessive rainfall during the last half of May and under the imposition
of cultivation, a single early preplant or preemergence application
were often not enough to provide season-long control of both common
lambsquarters and common ragweed (Table 9). Multiple applications gave
more consistent control Of these species throughout the season (Tables
10 and 11).

There were no significant crOp injury symptoms from early preplant
applications Of metribuzin, linuron, or cyanazine alone or in
combinations used in the soybean study; Only the sequential
application of linuron and alachlor resulted in crOp injury
significantly greater than the untreated check (Table 12L. The two
combined applications of linuron at (L84 kg/ha were excessive for this
soil type. Layby applications Of atrazine were applied in an attempt
to control weeds in the furrow without directing the herbicide near the
ridge and the soybeans which are very susceptible to atrazine.
Atrazine at 1.12 kg/ha applied in this manner fol lowing preemergence
treatments Of chloramben + alachlor (2.24 + 2.80 kg/ha) with metribuzin
(0.42 kg/ha) or linuron (0.84 kg/ha) resulted in 10% and 11% soybean
injury eighteen days after layby applications. Later Observations
noted excessive phytotoxicity on the soybeans treated with atrazine but
no visible injury from other layby applications.

Applications were made on soybeans at the 2 to 4 trifoliate leaf
stage when the plants were 10 to 15 cm in height on ridges that were 18
to 20 cm high. Common lambsquarters was at the 6-leaf stage (5 to 10

cm in height) and common ragweed was at the 6- to 8-1eaf stage (101x)

54

Table 11: Mid- and late-season evaluations of common lambsquarters and common ragweed
control with sequential herbicide applications of a preemergence application
followed by a layby application in ridge till-planted soybeans, l984.

 

 

 

 

 

Common Common
Rate Lambsquarters Ragweed
Treatment3 PRE LAYBY 7/3/84 10/11/84 7/3/84 10711/84
kg“ "a :
alachlor + metribuzin + 2.24 + 0.42
(alachlor + metribuzin) 1.12 + 0.28 100 a 100 a 100 a 100 a
alachlor + linuron + 2.24 + 0.84
(alachlor + linuron) 1.12 + 0.84 100 a 96 a 100 a 100 a
metolachlor + metribuzin + 2.24 + 0.42
(metolachlor + metribuzin) 1.12 + 0.28 100 a 99 a 100 a 99 a
oryzalin + metribuzin + 1.12 + 0.42
(alachlor + metribuzin) 1.12 + 0.28 100 a 99 a 99 a 95 a

 

1Means, average Of four evaluations, within one column followed by the same letter are not
significantly different at the 5% level using Duncan's multiple range test.

2Plots received a ridge- building cultivation on 7/3/.84 after evaluations on the same date
above were made.

3Each treatment includes paraquat (0.56 kg/ha) + X-77 (l/4% v/v) applied PRE.

 

55

Table 12: Ridge till-planted soybean injury evaluations, 1984.142

 

 

 

Rate
Soybean4
Treatment3 PRE LAYBY Injury
- --------------- kg/ha ------------------------ %----
chloramben + metribuzin 2.24 + 0.42
+ alachlor + (atrazine) + 2.80 1.12 10 ab
chloramben + linuron 2.24 + 0.84
+ alachlor + (atrazine) + 2.80 1.12 11 ab
metribuzin + alachlor 0.42 + 2.24
+ (metribuzin + alachlor) 0.28 + 1.12 15 ab
linuron + alachlor 0.84 + 2.24
+ (linuron + alachlor) 0.84 + 1.12 21 a
metribuzin + metolachlor 0.42 + 2.24
+ (metribuzin + metolachlor) 0.28 + 1.12 9 ab
metribuzin + oryzalin 0.42 + 1.12
+ (metribuzin + alachlor) 0.28 + 1.12 6 ab
untreated - - 0 b

 

1Means, average of four evaluations, within one column fol lowed by the same

letter are not significantly different at the 5% level using Duncan's multiple
range test.

zPlots received a ridge-building cultivation on 7/3/84.

3All treatments except untreated include paraquat “L56 kg/ha) + X-77 (l/4% v/v)
in initial treatment.

4Evaluations were méde on 7/26/84 (21 days after layby treatments were applied).

56

13 cm in height). Twelve days after application, all postemergence
treatments showed significant soybean injury compared to the untreated
check (Table 13). Atrazine at 1.68 kg/ha was post-directed followdng a
preemergence application of metolachlor at 2.24 kg/ha. While this
treatment provided the most consistent control of common lambsquarters
throughout the season, it resulted in 59% soybean injury three weeks
after application which was significantly greater than any
postemergence treatment evaluated at this time (Table 13).

A post-directed treatment of 2,4-D amine resulted in a 20% soybean
vigor reduction three weeks after application (Table 13). Subsequent
Observations showed excessive injury to soybeans following this
treatment.

None of the postemergence treatments provided satisfactory control
Of both common lambsquarters and common ragweed prior to the ridge-
building cultivation (Table 13). Due to the advanced stage Of growth
Of common lambsquarters at the time of postemergence application,
treatments including acifluorfen and bentazon were not effective.
Control of common ragweed with these herbicides was initially very
effective, but as with common lambsquarters, the weeds continued to
germinate later in the growing season and lack Of a residual herbicide
component resulted in poor late-season control.

In 1984, no injury resulted from early preplant applications
including metribuzin (0.56 kg/ha or 0.84 kg/ha), linuron (1.12 kg/ha),
cyanazine (2.24 kg/ha), and oryzalin + metribuzin (1.68 kg/ha + 0.56
kg/ha). Preemergence applications including linuron (0.84 kg/ha) and
metribuzin (0.42 kg/ha) with and without oryzaliri(1.12 kg/ha) also

resulted in essentially no visible injury.

 

57'

Table 13: Early and mid-season evaluations of common lambsquarters, common ragweed control,
and spygean injurvaith postemergence treatment in ridge till-planted soybeans,
D

 

 

1984.
Common Common Soybean
Rate Lambsquarters Ragweed injury
Treatment3 W 773/8_4_7l2'6784— ‘fi—TT—‘THS /26/8 7———7——/3/a4 126/84
------ kg/ha------- ------------—-.-----------x:-------------------------
metolachlor + 2.24
(acifluorfen +
bentazon) 0.56 + 0.84 50 b 64 b 92 a 98 a 66 b 5 bc
(acifluorfen + 0.56 +
bentazon + 0.84 +
fluazifop) 0.28 61 ab 89 a 91 ab 83 b 71 ab 14 bc
metolachlor + 2.24
(atrazine)* 1.68 89 a 90 a 66 c 93 ab 75 a 59 a
metolachlor + 2.24
(2.4-0 amine)‘ 0.56 87 a 99 a 78 b 98 a 31 c 20 be
untreated - - 0 c 0 c 0 d 0 c 0 d 0 c

 

1Means, average of four evaluations, within one column fol lowed by the same letter are not
significantly different at the 5% level using Duncan's multiple range test.

2Plots received a ridge-building cultivation on 7/3/84 after evaluations on the same date
above were made.

3Postemergence treatments, except 2.4-0 amine. include COC (ZJNlL/ha) and were applied on
6/21/84.

I

*Indicate treatments that were post-directed.

 

58

1985. An experiment was initiated on established ridges to
examine soybean tolerance and weed control when herbicides were applied
early preplant compared to the same herbicides applied preemergence.
Paraquat + X-77 (0.56 kg/ha + 1/4% v/v) was applied to all plots to
facilitate burndown of existing vegetation. All other herbicides used
in the experiment were tested to determine the soil residual effect Of
each respective herbicide<Nisoybean phytotoxicity. Early preplant
treatments were applied at generally higher rates than those used for
the preemergence counterpart to account for the removal Of soil on the
ridge from the till-planting Operation and loss Of available activity
from natural transformation processes occurring in and on the soil.

In 1985, under much drier growing conditions than the previous
year, significant soybean injury was Observed 19 days after planting
with treatments Of metribuzin UL56 kg/ha) applied early preplant, and
preemergence treatments of metribuzin (0.42 kg/ha) or cyanazine (1.12
kg/ha) (Table 14L. Symptoms were slight chlorosis and loss of vigor as
compared to the untreated plots. Oxyfluorfen applied early preplant at
1.12 kg/ha and preemergence at (L56 kg/ha exhibited severe stunting and
chlorosis at the same evaluation and resulted in the greatest soybean
vigor reduction. All other treatments including 1inuron,cwy2alin,
pendimethalin, an ester formulation of 2.4-0, and early preplant
applications Of the highest rates Of cyanazine or metribuzin, did not
result in significantly greater soybean injury than the untreated check
at this early evaluation. By mid-season, after the ridge-building
cultivation,ru>treatment resulted hisoybean injury significantly

greater than the untreated check (Table 14).

Table 14:

59

Mid- and late-season evaluations of common lambsquarters and dandelion
control and early- and mid-season soybean injury evaluations with early
preplant or preemErgence herbicide treatments in ridge till-planted
soybeans, 1985. '

 

 

 

common §3y5§ifi__-_
Rate lambsquarters dandelion injury
Treatment3 TEPP""PRE 77T7785TTT073785 77T7785"T0737§5 77T7785‘TT073785
---kg/ha---- %
metribuzin 0.84 100 a 92 a 98 a 95 a 6 d 0 a
metribuzin 0.56 98 a 83 a 99 a 86 ab 21 c 3 a
metribuzin 0.42 74 abc 75 ab 3 c 23 ef 20 c 8 a
linuron '1.68 87 ab 68 ab 98 a 95 a 3 d 4 a
linuron 0.84 83 abc 69 ab 23 bc 43 cde 1 d 9 a
cyanazine 2.24 98 a 88 a 96 a 95 a 6 d 0 a
cyanazine 1.12 36 cde 55 ab 25 bc 30 def 30 c 5 a
oxyfluorfen 1.12 76 abcd 70 ab 25 be 30 def 48 b 5 a
oxyfluorfen 0 56 29 de 28 be 3 c 54 cd 70 a 14 a
oryzalin 1.68 75 abcd 76 ab 0 c 20 ef 3 d 14 a
oryzalin 1.68 44 bcde 51 ab 0 c 38 cde 6 d 15 a
pendimethalin 2.24 91 ab 71 ab 0 c 33 cde 0 d ’ 6 a
pendimethalin 1.12 55 abcd 51 ab 0 c 28 def 4 d 9 a
2.4-0 ester 0.56 61 abcd 70 ab 99 a 88 ab 5 d 4 a
2.4-0 ester 0.56 68 abcd 49 ab 38 b 25 def 7 d 10 a
untreated - - 0 e 0 c 0 c 0 f 0 d 0 a

 

1Means. average of four evaluations, within one column followed by the same letter are

not signif

2Plots rece

icantly different at the 5% level using Duncan's multiple range test.

ived a ridge-building cultivation on 7/24/85.

3Each treatment, except untreated, includes paraquat (0.56 kg/ha) + X-77 (l/4% v/v)

applied pr

eemergence.

 

60

These data suggest that the early preplant applications tested,
although not ensuring tolerable soybean injury, may be less injurious
to soybeans due to the removal of excessive herbicide residues by the
till-planter. Oxyfluorfen, although applied at twice the rate early
preplant compared to the preemergence rate, resulted in significantly
less injury four weeks after planting. This was the case for both
cyanazine and metribuzin as well (Table 14).

Early preplant applications provided equal or greater weed control
than preemergence treatments (Table 14). An early preplant
application Of metribuzin at 0.56 kg/ha, cyanazine at 2.24 kg/ha, or
pendimethalin at 2.24 kg/ha gave 91% or greater control of common
lambsquarters 10 weeks after planting. By'comparison, preemergence
applications of metribuzin at 0.42 kg/ha, cyanazine at 1.12 kg/ha, or
pendimethalin at 1.12 kg/ha gave 74% or less control of this Species 10
weeks after planting. This may have been due to the lower rate of
herbicide application and the lack.of adequate rainfall before and
after the preemergence treatments. At the late-season evaluation only
early preplant applications of metribuzin at (L84 kg/ha or (L56 kg/ha
and cyanazine at2L24 kg/ha provided better than 80% control of this
weed. This suggests that there is an advantage to early preplant
applications when adequate rainfall for proper activation of residual
soil applied preemergence herbicides does not occur. Only applications
of linuron and the ester formulation of 2.4-0 did not follow this trend
(Table 14). Since 2,4-0 ester has limited persistence in the soil and
generally only controls weeds that have emerged at the time Of
treatment, timing did not result in greater benefit under the

conditions of delayed weed emergence.

61

Comparison of the two application timings for dandelion control
was even more dramatic; Early preplant applications of metribuzin.
linuron, cyanazine, and 2,4-0 ester provided significantly greater
control Of this perennial weed throughout the season (Table 14).
Although preemergence applications of metribuzin at 0342 kg/ha and
oxyfluorfen at 0.56 kg/ha exhibited some control Of dandelion at early
emergence Of this weed approximately four weeks after planting on June
6, control was never adequate throughout the season (Table 14L.The
data suggest that under conditions of insufficient rainfall, early
preplant application of residual herbicides may be necessary to control

dandelion in soybeans.

LITERATURE CITED

Conservation Tillage Proceedings NO. 4. Conservation tillage for
row crop production. 1985 Area Meetings in Nebraska. Univ.
Nebraska and LLSJLA. Extension Service. pp. 51-53, 59-60, 69-70,
111-120, and 133-141.

Fawcett, J. A., R. S. Fawcett, L. G. Brenneman, and J. L.
Creswell. 1982; Early preplant vs. planting-time herbicides for no-
till corn across Iowa. Proc.North Cent.Weed Cont.Conf.37z40-
43.

Fawcett, R. S.,lu G. Brenneman, J. L. Creswell. and G. B.
Vincent. 1982. Early preplant vs. planting-time herbicides for
nO-till soybeans across Iowa. Proc.North Cent.Weed Cont.Conf.
37:69-71.

Fawcett, R. S., M. 0. K. Owen, and P. C. Kassel. 1983. Early
preplant treatments for weed control in nO-till corn and soybeans.
Proc.North Cent.Weed Cont.Conf.38:112-113.

Fawcett, R. S., M. 0. K. Owen, and J. F. Lux. 1984. Early
preplant, preemergence, and postemergence applied herbicides for
weed control in nO-till corn at the Curtiss Farm, Ames, Iowa, 1984.
Res. Rep. North Cent. Weed Cont. Conf. 41:123-125.

Griffith, D.FL, J. V. Mannering, 0. B. Mengel, S. 0. Parsons, T. T.
Bauman, 0. H. Scott, F. T. Turpin, and 0. H. Doster.1982. A guide to
til l-planting for corn and soybeans in Indiana. Ext. Bull. ID-148,

Purdue Univ. COOperative Extension Service.

62

10.

11.

12.

13.

14.

15.

16.

63

Kapusta, G., and R. L. Wolff. 1985. Weed control in ridge vs.
flat-plant corn and soybeans, 1985. Res. Rep. North Cent. Weed
Cont.Conf.42:299.

Lueschen. W. E., and T. R. Hoverstad. 1985. Weed control in
ridge-til led corn at Waseca, MN, in 1985. Res. Rep. North Cent.
Weed Cont. Conf. 42:290-291.

Moomaw, R. S., and A. R. Martin. 1984. Cultural practices
affecting season-long weed control 'hi irrigated corn (23g gays).
Weed Sci. 32:460-467.

Moomaw, R. S., and A. R. Martin. 1978. Weed control in reduced
tillage corn production systems. Agron J. 70:91-94.

Moomaw, R., A. Martin, and D. P. Shelton. 1982. Weed control in
reduced tillage corn. Nebguide G74-123, Univ. Nebraska
COOperative Extension Service.

Moomaw, R. S., A. R. Martin, and R. G. Wilson Jr. 1983. Layby
herbicide application RM‘season-long weed control in irrigated
corn (133mm). Weed Sci. 31:137-140.

Staniforth, 0.1L, and W. G. Lovely. 1975. Weed control systems
for nO-till soybeans. Proc. North Cent. Weed Cont. Conf. 30:60.
Stobbe, E. H. 1978. Weeds and weed control with reduced
tillage. Proc. North Cent. Weed Cont. Conf. 33:29-30.

Stougaard, R. N., G. Kapusta, and G. Roskamp. 1984. Early

preplant herbicide applications for no-till soybean (Glycine max)

 

weed control. Weed Sci. 32:293-298.
Wicks, G. A., and B. R. Somerhalder. 1971. Effects of seedbed
preparation for corn on distribution of weed seed. Weed Sci.

19(6):666-668.

 

CHAPTER 3
CROP YIELD AND NEED CONTROL AS INFLUENCED BY
HERBICIDE APPLICATION AND CULTIVATION
ABSTRACT

Broadcast applications of the herbicides tested provided greater

than 91% control Of common ragweed (Ambrosia artemisiifolia L.) and

 

common lambsquarters (Chenopodium album L") in both corn and soybeans

 

grown on ridges with and without cultivation. Banded applications of
the same residual herbicides without cultivation resulted in 70% or
less control of the two weed species. However, when one cultivation
followed a banded application, control Of common ragweed in soybeans
and common lambsquarters in both crOps was not significantly different
from broadcast treatments at any level Of cultivation. Two
cultivations alone without herbicide application provided 90% control
of common ragweed in till-planted soybeans. NO Significant differences
in yield were Observed in either crop due to differences in herbicide

programs or cultivation.

64

INTRODUCTION

Conservation tillage systems are gradually gaining acceptance in
agriculture as a means of effectively control ling erosion and water
loss through management of surface residues. A key feature Of these
systems is a reduction in tillage. Although benefits Of reduced
tillage such as erosion control and reduced energy expenditure may be
Obtained, there have been reports Of reduced weed control in these
systems. Griffith et. a1. (18) found that crOp germination and weed
control tended to be more of a problem with nO-plow systems across five
soil types in Indiana compared tO conventional tillage systems. These
problems were accentuated on poorly drained, fine-textured soils as
compared to well-drained, coarse-textured soils.

The ridge till-plant system is well suited for medium-textured,
well-drained soils (16, 18, 38, 39). Galloway et. a1. (16) and others
(18, 19, 38, 43) suggested that ridge till-planting may be successful
on poorly drained, fine-textured soils if ridges are pronounced and
kept free of residues to ensure better drainage and thus, a warmer and
dryer seedbed. Under proper management, till-planting on ridges Offers
a higher degree of erosion control while providing a residue-free
seedbed and allows for timely cultivations to control weeds. Several
studies have shown that a ridged configuration is beneficial for crOp
growth and erosion control (1, 8, 41, 50). Some have attributed
better stands and crOp emergence to more available moisture in the

ridge (1, 3, 15, 46).

65

66

In the ridge till-plant system, the seed is planted in the ridge
and into the Old crop row where soil is warmer and better drained than
in the furrow. Along with crop residue on the ridge, weed seed is
moved with the soil from the crest of the ridge into the furrows.
Wicks and Somerhalder (47) found that the till-planter left only 30% as
many weed seeds in the corn row as compared to seedbeds prepared by
plowing, disking, and harrowing. Others (6, 23, 46) have reported
lower weed pOpulations, particularly annual grasses, in the ridge till-
plant system compared to conventional and other conservation tillage
practices.

Greater reliance on herbicides and better management skills may be
required in the ridge till-plant system (10, 32L Special emphasis on
controlling perennial weeds with herbicides maylxanecessary since
these species are less likely to be controlled by shallow tillage (2,
20, 37, 45, 48). Annual weeds can be control led effectively in this
system while saving labor (11, 14,19, 39), energy (11, 19, 39, 51),
soil moisture (1, 3, 15, 46) and soil (4, 5,10,11,12, 13, 22, 24,
25, 26, 27, 28, 29, 36, 49, 51) when compared to conventional tillage
systems.

Moomaw and Martin (31) investigated weed control in till-planted
and slot-planted corn on ridges and found that till-planting was less
dependent on herbicides due to increased surface tillage. Maximum corn
yield was achieved in the till-plant system with banded applications of
preemergence herbicides followed by one cultivation. Although
broadcast treatments controlled weeds effectively in the till-plant
system, the design of the test did not show weed control effects

without cultivation. Corn that was slot-planted on ridges, a: system

67

featuring nO-tillage on the ridge, benefited from two cultivations
rather than one in terms of crOp yield and weed control.

It is generally agreed that the number of cultivations required in
the till-plant system is dependent on the degree of weed infestation
and herbicide efficacy. Studies (30, 31) have demonstrated that
mechanical cultivation alone gave weed control not significantly
different than any Of the treatments including both herbicides and
cultivation in till-planted corn. Lane and Gaddis (26) suggested that
a banding Of herbicides is more necessary in soybeans or milo than in
corn in this system. Under the dryland conditions in Nebraska, they
also suggested that broadcast applications are not necessary since
cultivation will control weeds between the crOp rows. Regehr (38)
suggested that two cultivations are usually needed if herbicides are
banded on the ridge. Burnside and Wicks (7) found that a combination
Of cultivation and herbicides gave more dependable weed control in
sorghum than either method used alone. Gebhardt (17) substantiated
these results in soybeans.

In Nebraska and other states implementing the ridge til l-plant
system, the approach used to control weeds has been to apply
preemergence herbicides and control emerging weeds as they occur with
light tillage or postemergence herbicides (9, 31, 32). Several
studies have shown that tillage has little influence on crOp yield in
the absence of weeds (21, 44L. Where good tilth and soil structure
exist, cultivation was adequately substituted by herbicides for weed

control. At least two tillage operations, including till-planting and

68

a ridge-building cultivation, are required if the ridge till-plant
system is to be maintained (16, 19, 26, 38, 39, 42, 43, 50). Today,
the ridge till-plant system has evolved to include generally no more
than three tillage Operations in one growing season (19, 26, 38, 39,
50). Research in ridge till-planting has included evaluation Of
preplant disking (40), rotO-tilling ridges at planting (38), and chisel
plowing corn stalks prior to a fall ridge-building (38L. These tillage
Operations were done as variations of preparing a suitable seedbed
free from residues. However, it was noted that these variations,
although useful in many situations, will incorporate weed and volunteer
seed in the crOp row and possibly require additional weed control
measures (15, 26, 38).

The Objectives of this study were to: a) compare weed control in
the ridge till-plant system with a zero, one, or two cultivation
variable; b) compare preemergence herbicides and application method
across three cultivation levels; and c) examine the effect of
cultivation and herbicide application on crOp yield in the ridge till-

plant system.

MATERIALS AND METHODS

Corn (lea mays L.) and soybean (Glycine max (L.) Merr.)

 

experiments were conducted on established ridges built the previous
year at North Star in Gratiot County, Michigan where the previous crop
was corn. 'The experiments were designed asaithree factor factorial
with one split. The factors were 5 herbicide treatments, broadcast or
banded application, and 0, l, or 2 cultivations. Main plots were
number of cultivations. Subplots consisted Of five preemergence
treatments that were either banded in 25 cm bands or broadcast.

Both crOps were till-planted on ridges with a 4-row Buffalo All-
Flex1 till-planter in 76 cm rows on May 8. The corn variety used was
'Pioneer 3744' and the soybean variety was 'Corsoy 79'. Each plot was
three meters wide by 15 meters long and included four rows of the crop.
Plots were trimmed to 13.7 meters length for uniformity in harvesting.
The center two rows were then harvested on October 30 and yields were
computed based on corn at 15.5% moisture and soybeans at 13% moisture.

The herbicide treatments for both studies are listed in Tables 1
and 2. All broadcast herbicide treatments included paraquat (0.28
kg/ha) + X-77 (1/4% v/v) and were applied with a tractor mounted
compressed air Sprayer in 215 L/ha water carrier at 206 kPa. Banded

treatments were applied with a tractor mounted compressed air sprayer

1Manufactured by Fleischer Mfg” Box 848, Columbus, NE 68601.

69

70

Table l: Preemergence herbicide

corn.

treatments for ridge till-planted

 

Herbicide Treatment

Rate (kg/ha)

 

alachlor + atrazine
alachlor + atrazine + cyanazine
metolachlor + atrazine

metolachlor + atrazine + cyanazine

2.80 + 1.68
2.80 + 0.84 + 1.68
2.24 + 1.68
2.24 + 0.84 + 1.68

 

71

Table 2: Preemergence herbicide treatments for ridge till-planted

 

 

soybeans.
Herbicide Treatment Rate (kg/ha)
alachlor + metribuzin 2.80 + 0.42
alachlor + linuron 2.80 + 0.84
alachlor + chloramben + metribuzin 2.80 + 2.02 + 0.42

alachlor + chloramben + linuron 2.80 + 2.02 + 0.84

 

72

in 299 L/ha water carrier at 206 kPa and drOp nozzles were used to
achieve the 25 cm band on the tilled ridges. Soybean treatments were
applied the same day as planting and corn treatments were applied one
day after planting.

Common lambsquarters (Chenopodium album LJ and common ragweed

 

(Ambrosia artemisiifolia LJ were the predominant annual broadleaf

 

weeds in both studies. Populations Of both weeds were light to
moderate but uniform throughout the studies. The soil in the corn
study was a clay loam texture with pH 7.0 and 2.7% organic matter and
in the soybean study, was a clay loam texture with pH 7.3 and 2.6%
organic matter.

A 4-row Buffalo All-Flex2 cultivator was used for all
cultivations. Plots in both crops receiving two cultivations were
first cultivated on June 21 with disk hillers set to throw soil and
residues between the crap rows. Plots cultivated once and those
receiving a second cultivation in corn were cultivated on July 1 and in
soybeans on July'24 with disk hillers set tormave soil and residues
into the row to reform ridges. Ridges were approximately 18 to 22 cm
in height after this cultivation. By comparison, main plots that
received no cultivation were approximately 10 to 13<uniriheight by
mid-season. Corn was 15 to 36 cm in height (V-5 to V-8)3 at the first
cultivation timing. At this same timing, soybeans were 7 to 13 cm in

height (V-2)4. At the second cultivation, corn was 36 to 71 cm in

2Manufactured by Fleischer Mft., Box 848, Columbus, NE 68601.

3How a corn plant develops. Special Report No. 48, Iowa State
University, Ames, Iowa.

4How a soybean plant develops. Special Report No. 53, Iowa State
University, Ames, Iowa.

73

height at the V-7 to V-9 stage of growth, and soybeans were 36 to 66 cm
in height at the V-6 to V-10 stage of growth.

Analyses of variance were computed on all data. ‘The difference
between treatment means was tested with LSO values at the 5% level of

significance.

RESULTS AND DISCUSSION

No significant treatment effects or interactions existed in either
corn or soybeans due to differences in herbicide programs. Mid-season
visual evaluations of annual weed control were therefore combined based
on method Of application and the number of subsequent cultivations
received after herbicides were applied.

Broadcast applications of the herbicides tested provided greater
than 91% control of common ragweed or common lambsquarters in corn and
soybeans regardless of the level of cultivation (Figures 1, 2, 3, 4L
Banded applications of the same residual herbicides, followed by no
cultivation, resulted in 70% or less control of the two weed species.
However, when one cultivation followed a banded application, control of
common ragweed in soybeans and common lambsquarters in both crops was
not significantly different from broadcast treatments at any level of
cultivation (Figures 1.2, 3,4). These results Support the findings
of Moomaw and Martin (31) in the ridge till-plant system and Moomaw and
Robison (33, 34, 35) on flat-tilled soil and suggest that banded
herbicide applications with cultivations are a legitimate option in
this system.

In the soybean study, two cultivations alone provided 90% control
of common ragweed (Figure 3L However, even with two cultivations,

herbicide application improved weed control. Evaluation of common

74

75

Figure 1. Common ragweed control in ridge til L-planted corn as
influenced by method of herbicide application and

cultivation, 7/30/85.

76

mzo_._.<>_.530 mo mwmfinz

N

km<uo<omm
Dmaz<ml ll
mogmmmI oz 1.1:

H. 8.8..

_

_

\-c1

 

a.
UN
om
0v
0m
0m
Om
am
am
DD.

[XI ‘IUHLNDO UBEMSVH NDWWUCJ

77

Figure 2. Common lambsquarters control in ridge till-planted corn as
influenced by method of herbicide application and

cultivation, 7/30/85.

78

mZD_._.<>_._.i=._U n5 mum—2:2

 

N _ o
_ _ _
55.20% 11 .\
Boz<m . l \
mggmmm: oz 11 \
. \
H 1 we own .
\
.\
s\ \
-\-\ \
1.111 \
\

 

D—
ON
0m
Dv
am
am
on
am
am
DD—

[ZI ~IE11:U.NEL'.1 SHBIHVHDSBWV'I NUWWUIJ

 

79

Figure 3. Common ragweed control in ridge till-planted soybeans as
influenced by method of herbicide application and

cultivation, 8/8/85.

80

mzo_._.<>_._.i_:u n5 mmmEDZ

 

N _ a
_ _ F
5520mm 1 .\
amazem .. I .\
865$: 02 11.. .\
. \
H .. moamo \.
.\
\.
\\ \
.\- \
\i\ \

 

D _
ON
Dm
Dv
0m
am
on
0m
0m
DD _

[X] TIUHLNDCJ DEBMSVH NDWWDCJ

 

81

Figure 4. Common lambsquarters control in ridge till-planted soybeans
as influenced by method of herbicide application and

cultivation, 8/8/85.

82

Pm<uo<omm

N

b

mzo_._.<>_._.i_:u ”.0 mum—>52

 

Dwoz<m1 il
mn=n=mmmI Dz .l..|.|

H .. 8.8..

_

 

D _
am
0m
9»
am
am
am
0m
0m
00 _

[X] ‘lDHiNDCl SHEIHVHUSBWVT NDWWDC]

83

lambsquarters control at mid-season also showed limited necessity of
herbicide application as control approached 89% when no herbicide was
applied and two cultivations followed (Figure 4). However, broadcast
herbicide application improved control Of this weed as well.

In the corn study, although cultivation alone provided 80% or
greater control Of common lambsquarters, control Ofifluetwo annual
weeds was less than where cultivation was preceded by either a banded
or broadcast herbicide application (Figures 1, 2L. In addition, a
broadcast herbicide application provided significantly greater control
of both species than two cultivations alone.

Two cultivations generally improved control of both weed species
as compared to one cultivation in both crOps. However, considering the
populations of the annual weeds present in the studies and the adequacy
of the weed control attained, the second cultivation following
herbicide treatmentln/either application method did not contribute
greatly to the total weed control obtained.

No significant differences in yield were observed in either crop
(Table 3). This may have been due to the generally low populations of
weeds present in the studies and the lack of their ability to compete
sufficiently with the crops. Weed establishment was delayed in
comparison to the crop establishment due in part to the lack of
adequate rainfal'liat planting and the effective seedbed preparation

generated by the till-planter.

84

Table 3: Ridge till-planted corn and soybean yields as influenced

by method Of herbicide application and cultivation,

 

 

 

1985.
Method Of Application1 Corn Soybean
-------- (kg/ha x lO)--------

Banded 0 cultivation 698 258

l cultivation 714 274

2 cultivations 737 269
Broadcast O cultivation 748 265

l cultivation 765 274

2 cultivations 733 265
No Herbicide 0 cultivation 657 263

l cultivation 702 287

2 cultivations 704 272

LSD .05 = 286 73

 

1Combined all herbicide treatments.

LITERATURE CITED

Adams, J. E. 1967. Effects of mulches and bed configuration. I.
Early-season soil temperature and emergence of grain sorghum and
corn. Agron J. 59:595-599.

Amemiya, M. 1977. Conservation tillage in the western corn belt. J.
Soil and Water Cons. 32(1):29-36.

Amemiya, M. 1968. Tillage-soil water relations of corn as
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Baker, J. L., and H. P. Johnson. 1979. The effect of tillage
systems on pesticides in runoff from small watersheds. Trans. Amer.
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Buchele, W. F., E. V. Collins, and W. G. Lovely. 1955. Ridge
farming for soil and water control. Agr. Eng. 36:324-329.

Buhler, 0. 0., and T. C. Daniel. 1984. Influence of tillage systems
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Burnside, O. C., and G. A. Wicks. 1964. Cultivation and herbicide
treatments of dryland sorghum. Weeds 12:307-310.

Burrows, W. C. 1963. Characterization Of soil temperature
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85

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111-120, and 133-141.

Conservation Tillage: Things to consider. 1985. U.S.D.A. Ag.
InfO.Bull. #461.

Dickey, E. C., A. R. Rider, and P. W. Harlan. 1981. Tillage
systems for row crOp production. Nebguide 680-535, Univ. Nebraska
COOperative Extension Service.

Dickey, E. C., 0. P. Shelton, P. J. Jasa, T. R. Peterson. 1985.
Soil erosion from tillage systems used in soybean and corn
residues. Trans. Amer. Soc. Agr. Eng. 28(4):1124-1129.

Dickey, E. C., 0. P. Shelton, P. J. Jasa, T. R. Peterson. 1984.
Tillage, residue and erosion on moderately sloping soils. Trans.
Amer. Soc. Agr. Eng. 27(4):1093-1099.

Doster, 0. H., and J. A. Phillips. 1973. Costs, inputs and
returns: humid and subhumid areas. Proc. Cons. Tillage Conf. Soil
Cons. Soc. Am. pp. 163-168.

Fisher. W. F., and 0. E. Lane. 1973. Till-planting. Proc. Cons.
Tillage Conf. Soil Cons. Soc. Am. pp. 187-194.

Galloway, H. M., D. R. Griffith, and J. V. Mannering. 1981.
Adaptability of various tillage-planting systems to Indiana soils.
Ext. Bull. AY-210, Purdue Univ. COOperative Extension Service.
Gebhardt, M. R. 1981. Preemergence herbicides and cultivations for

soybeans (Glycine max). Weed Sci. 29(2):165-168.

 

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87

Griffith, 0. R., J. V. Mannering, H. M. Gal loway, S. 0. Parsons,
and (LB. Richey. 1973. Effect of eight tillage-planting systems on
soil temperature, percent stand, plant growth, and yield of corn
on five Indiana soils. Agron. J. 65:321-326.

Griffith, D. R., J. V. Mannering, 0. B. Mengel , S. 0. Parsons, T.
T. Bauman, 0. H. Scott, F. T. Turpin, and 0. H. Doster. 1982. A
guide to till-planting for corn and soybeans in Indiana. Ext.
Bull. ID-148, Purdue Univ. COOperative Extension Service.
Griffith, 0.1L, J. R. Mannering, and W. C. Moldenhauer. 1977.
Conservation tillage in the eastern cornbelt. J. Soil and Water
Cons.32(1):20-28.

Hinesly, T. 0., E. L. Knake, and R. 0. Seif. 1967. Herbicide
versus cultivation for corn with two methods of seedbed
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Johnson, H.1L, J. L. Baker, W. 0. Shrader, and J. M. Laflen.
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from snmi‘l watersheds. Trans. Amer. Soc. Agr. Eng. 22:1110-1114.
Johnson, M. 0., 0. L. Wyse, and W. E. Lueschen. 1984. The
influence of herbicide formulation on weed control in reduced
'tillage systems. Proc. North Cent. Weed Cont. Conf. 39:49-50.
Johnston, J.FL 1973.Conservation and production systems for a
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Laflen, J. M.,(L L. Baker, R.(L Hartwig, W.li Buchele, and H.
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systems.Trans.Amer.Soc.Agr.Eng.21:881-885.

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88
Lane, 0. E., and R. Gaddis. Conservation production systems for
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Extension Service.
Moldenhauer, W. C. 1985. A comparison of conservation tillage
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89

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reduces soil losses. Agr. Eng. 45:256-257.

CHAPTER 4
SUMMARY AND CONCLUSIONS

In the studies conducted for weed control in corn and soybeans
grown on ridges with the til l-plant system, soil applied herbicides
were shown to be a necessary component of a total weed control
strategy. Early preplant applications Of residual herbicides may be
beneficial in this system when rainfall is inadequate at planting to
position and activate herbicides, especially in soybeans if planting is
delayed allowing early establishment of weeds. High rates of
herbicides applied early preplant, which may cause crop injury when
applied preemergence, have been shown to be tolerated by the crap when
the herbicide residue is partially removed by the till-planter.
Therefore, early preplant treatments represent an Option for
maintaining crop safety and controlling early germinating annual weeds,
established winter annuals, and possibly perennial weeds between
seasons when crops are produced in the ridge till-plant system.

Sequential applications of an early preplant application followed
by a preemergence application, or a preemergence application followed
by layby herbicide application, at the timing of the final cultivation
in the field provided the most consistent and complete season-long
control in both crops. Early preplant applicationscnimetribuzin,
linuron, or cyanazine were more effective in controlling dandelion than

the same treatments applied preemergence.

91

92

Herbicide treatments applied in these studies were aimed at
providing season-long annual weed control and were developed around the
tillage requirements of the till-plant system. Although not addressed
in this paper. perennial weeds can become a problem in the ridge till-
plant system due to lack Of sufficient deep tillage to control these
Species (Appendix 2). Reliance on the action of the til 1-planter to
diSplace residues and weed seeds from the row and cultivation as a
means of control ling existing weeds, is seen as an advantage in this
system and has been documented. However, weed control programs were
examined as an alternative to cultivation to determine the necessity of
broadcast applications of herbicides to control weeds in the furrow.
In studies conducted in 1985, a broadcast application of residual
herbicides withaiburndown component gave greater weed control than
banded applications. However, with the addition of one or two
cultivations, banded applications gave comparable annual weed control.
This suggests that when weed pOpulations are low, as they were in these
studies. reliance on herbicides is reduced. In a separate study where
timing Of herbicide application was examined for weed control,
postemergence herbicide treatments tested as the primary means Of weed
control generally gave unsatisfactory control compared with treatments
including a soil application of herbicides. This may have been due to
poor coverage Of weeds with these postemergence herbicides or more
rapid metabolism and detoxication of the herbicide by the larger weeds.

It was an Objective of studies conducted to determine the extent
of cultivation and herbicide application needed to maximize yield in

the ridge till-plant system. Although the contribution of cultivation

93

as a component in the weed control strategy on ridges was found to be
important in reducing weed establishment, especially when herbicides
were row banded, no significant differences in yield were observed due
to differences in herbicide programs, method of application or degree
of cultivation. This was due to early crOp establishment and lack of
competition from light to moderate weed infestations that developed

more slowly than the crop.

 

 

94

Appendix 1. Rainfall for April through August for the North Star site

for 1984 and 1985, Gratiot County, Michigan.

 

 

 

April May June July August
Day 1984 1985 1984 1985 1984 1985 1984 1985 1984 1985
.......................... cm ---_--------------------_-—--—-——-

1 - 0 58 - - - - - - - 0 36

2 - - 0.03 - - - - - - -

3 - 0 36 0 03 - 0.30 - - - - -

4 _ - - - - - - - _ -

5 0.33 1.50 0 05 0.13 1.14 - - O 53 - 1.68

6 0.56 1.60 - 0.03 0.71 - 1.04 - - 1.07

7 - 0 05 - - - - - - 0.03 0.33

8 - - - - — 0.10 - 0.10 - -

9 - - 0.05 - - 1.32 - - 1.09 -
10 - - - - 0 33 - 0.03 0.05 1.22 -
11 - 0.10 0.03 - - 0.05 6.05 - - 0.05
12 - 0.05 - - - 0.64 0 10 - -
13 0.64 - 0.81 - 0 08 0.05 - - - 0.56
14 0.18 - 1.65 - 0 03 - - 0.03 - 0.08
15 0.48 0 41 - - - - - 0.08 - 0.36
16 0.56 - - 1 07 - 3.05 - - - 0.13
17 0.89 - - 0 08 1.80 0.46 - - - -
18 0.43 0.81 0 13 - 2.84 - 0 03 - - 2.18
19 - 0.58 0 08 - - - - - 0 28 0.46
20 - 0.89 - - - - - 0 86 - -
21 - - - 0 36 - - - - -
22 - - 0.13 - - - - - - -
23 2.03 5.84 - - 0.94 - - - -
24 0.15 - - - - - 0 18 - - 3 51
25 - 0.64 0.99 - - - - - - 3.30
26 0.15 - 0.81 - - - - 5.26 - -
27 - - - 2.16 0.46 - 0 25 - - -
28 - - 0.10 0.84 — - - - 0.38 -
29 - - 3.07 - - - - - 0.13 0.28
30 0.20 - 0.10 - - - - 1.50 0.03
31 - - 0.03 0 25 - - - 0.13 - 0.05

 

TOTAL 6.60 7.57 13.90 4.92 7.69 6.61 7.68 7.04 4.63 14.43

95

Appendix 2. Pre-harvest herbicide treatments for Canada thistle
control in ridge till-planted soybeans at the North Star

site, Gratiot County, Michigan, 1984.

 

 

Treatment1 Rate 10/23/84 6/6/85
------ kg/ha----- --------%--------
glyphosate 1.68 20d 99a
glyphosate 2.52 20d 98a
bentazon + COC 1.12 + 2.34 L/ha 63a 17cd
atrazine + COC 2.24 + 2.34 L/ha 37bc 20cd
dicamba 1.12 33bcd 52bc
dicamba 2.24 43b 95ab
2,4-0 ester 1.12 23cd 40cd
2,4-0 ester 2.24 20d 42cd
mixture of free 2,4-0 acid
+ 2.4-0 butoxyethyl ester2 2.24 27cd 40cd
mixture of free 2,4-0 acid +
propylenediamine salt of 2,4-D3 2.24 30bcd l3cd
dicamba + 2,4-0 ester 0.56 + 0.56 23cd 53bc
Untreated -- 0e 0d

 

IApplied on 10/11/84 to mature soybeans and Canada thistle at
80% bud stage.

2Active ingredients in commercial formulation Weedone 638.
3Active ingredients in commercial formulation of Dacamine 4D.

Reliance on selective and nonselective herbicides are seen as an
Option for controlling perennials that are not controlled by
cultivation in the ridge till-plant system. Canada thistle (Cirsium
aryense (L.) Scop.) was one such species detected as it problem
perennial in soybeans grown on ridgesn A study was initiated with
herbicide treatments that were applied to mature soybeans immediately
prior to harvest while Canada thistle was in the bud stage Of
{eproduction. The visual evaluations of control Of this weed are

isted.

       

MIC T

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