i'rCJjLCi
iiXLii:
PROJECT
LEADER:
OBJECTIVES:
£.valuation
of
Continuous
Cropping
with
Tall
Wheatgrass
Barriers
Jerald
W.
Bergman,
Superintendent,
Eastern
Agricultural
Research
Center,
Sidney,
Motnana
To
determine
the
feasibility
of
continuous
spring
wheat
crop
ping
of
small
grains
on
dryland
when
the
best
known
methods
of
weed
control,
fertilizer
practices,
and
other
management
practices
are
applied
in
conjunction
with
tall
wheatgrass
barriers.
In
evaluating
tall
wheatgrass
barriers
for
con
tinuous
spring
wheat
cropping,
the
following
factors
will
be
documented
each
year:
1.
Crop
yield
2.
Disease
problems
associated
with
continuous
cropping
in
grass
barrier
systems
3.
Insect
problems
associated
with
continuous
cropping
in
grass
barrier
systems
4.
Tillage
problems
associated
with
continuous
cropping
5.
Rodent
problems,
if
any,
associated
with
tall
wheatgrass
barriers
6.
Weed
problems
associated
with
continuous
cropping
between
tall
wheatgrass
barriers
MATERIALS
AND
METHODS:
The
tall
wheatgrass
barriers
being
evaluated
in
this
study
were
first
established
in
the
summer
of
1965
as
part
of
another
experi
ment.
As
originally
planned,
the
experiment
contained
2-row
grass
barriers
with
a
distance
of
42
inches
between
the
grass
rows.
Four
of
the
barrier
strips
had
inside
cropping
dimensions
of
30*
x
265*.
Three
other
barriers
were
of
60*
X
265*
inside
dimensions.
For
check
purposes,
an
exterior
area
without
grass
barriers
was
provided
for
in
the
experiment.
During
the
1966-71
crop
years,
this
grass
barrier
system
was
cropped
each
ye^r
to
either
spring
or
winter
wheat.
Data
was
collected
on
the
efficiency
of
the
barriers
in
trapping
snow,
preventing
soil
erosion,
and
affecting
temperature
relations
over
the
crop.
No
fertilizer
treatments
were
applied
to
the
site
and
no
program
of
controlling
annual
weeds
was
instituted.
By
1971,
the
fer
tility
status
of
the
soil
had
declined
to
a
low
level
and
such
annual
weeds
as
wild
oats,
green
foxtail,
and
yellow
foxtail
infested
the
land
to
a
moderately
serious
degree.
Beginning
in
1971,
an
attempt
to
control
these
weed
popula
tions
with
herbicides
was
initiated.
Safflower
was
grown
in
the
barrier
system
in
1972,
but
thereafter
spring
wheat
has
been
continuously
cropped
in
the
barrier
system
utilizing
effective
herbicides
and
fertilizer.
The
30
ft.
barriers
were
eliminated
in
the
fall
of
1979
to
provide
two
additional
60
ft.
barriers
for
further
continuously
cropped
studies
under
no-till
and
till-and-
plant
conditions.
The
decision
to
eliminate
the
30
ft.
barriers
was
based
on
our
research
results
indicating
the
30
ft.
barriers
were
too
narrow
to
com
pensate
for
yield
loss
due
to
land
removed
from
crop
production.
MATERIALS
AND
METHODS
FOR
THE
1988
SEASON:
No
tillage
was
performed
on
the
plots
in
the
fall
of
1987
and
the
stubble
was
allowed
to
stand
over
winter
to
collect
snow.
Ammonium
nitrate
at
the
rate
of
100
lbs/acre
was
applied
on
November
10,
1987.
All
of
the
plots
were
sprayed
with
Roundup
herbicide
on
April
12th
at
the
rate
of
1.5
pints/acre
to
control
volunteer
tall
wheatgrass
and
other
emerging
weeds.
On
April
21st,
the
plots
scheduled
for
tillage
were
worked
twice
with
a
tandem
disk
and
harrow,
except
the
summer
fallow
plot
which
was
triple
K'd
twice.
Im-
mediately
after,
the
tilled
plots
were
seeded
to
Amidon
spring
wheat
at
a
rate
of
78
lbs/acre.
A
7-inch
single
disk
John
Deere
press
drill
was
used.to
seed
the
plots.
The
no-till
plots
were
also
seeded
on
April
21st
using
a
Versatile
Noble
No.
2000
no-till
drill
with
9-inch
row
spacing
at
the
rate
of
78
lbs/acre.
^
The
type
of
tillage
and
planting
for
the
various
plots
in
1988
were
as
follows:
60
Ft.
Barriers
-
Continuous
Crop
p-»
Plot
A
-
no-till
and
no-till
planting
Plot
B
-
spring
till
and
conventional
seeding
n
Plot
C
-
no-till
and
no-till
planting
Plot
D
-
spring
till
and
no-till
planting
Plot
E
-
spring
till
and
conventional
seeding
Plot
F
-
spring
till
and
conve.ntional
seeding
(40
ft.
barrier
for
this
plot
only)
Open
Field
Stubble
-
Continuous
Crop
Plot
G
-
no-till
and
no-till
planting
Plot
H
-
spring
till
and
conventional
seeding
Summer
Fallow
-
(wheat-fallow)
lotation
Plot
1
-
summer
fallow
Plot
J
-
spring
till
and
conventional
seeding
on
fallow
On
April
26th,
all
the
plots
were
sprayed
with
1
cuart/acre
of
Roundup
herbicide
to
control
volunteer
wheatgrass.
On
May
19th,
all
the
plots
were
sprayed
with
1.5
pints/acre
of
Bronate
herbicide
for
broadleaf
^^eed
control.
RESULTS
AND
DISCUSSION:
Precipitation
as
rain
or
snow
occurred
at
this
site
during
the
September
1987
through
August
1988
period
as
follows:
Month
and
Year
Inches
of
Moisture
September
1987
October
1987
November
1987
December
1987
January
1988
February
1988
March
1988
April
1988
May
1988
June
1988
July
1988
August
1988
Total
0.92
0.10
0.21
0.05
0.56
0.49
0.58
0.17
0.79
1.27
0.92
0.12
6.18
All
of
the
plots
in
the
study
were
harvested
on
July
26,
1988.
Grain
samples
from
the
summer
fallow
plot
were
obtained
for
test
weight
and
protein
analyses
Harvest
data
was
not
obtained
from
any
of
the
continuous
spring
wheat
plots
due
to
complete
crop
loss
(death
of
plants)
due
to
the
extreme
drought.
Method
of
Seeding
Plant
Height
Inches
Test
Grain
Weight
Protein
Lbs/Bu.
Percent
Yield
Bu/Acre
1.
60
Ft.
Barriers
Plot
A
no-till
&
plant
0
0
Plot
B
till
&
plant
0
0
Plot
C
no-till
&
plant
0
0
Plot
D
till
&
plant
0
0
Plot
E
till
&
plant
0
0
Plot
F
till
&
plant
0
0
2.
Open
Field
Stubble
Plot
G
no-till
0
0
Plot
H
till
&
plant
0
0
3.
Summer
Fallow
Plot
I
13.0
57.5
18.4
3.7
r«n
Grain
yields
in
1988
ranged
from
0
bushels/acre
for
the
continuous
cropping
to
3.7
bushels/acre
for
summer
fallow.
Surprisingly,
the
fungal
diseases
Pyrenophora
trichostoma
(tan
spot)
and
Septoria
were
noted.
The
incidence
of
disease
was
light
to
moderate
in
the
no-till
plots
and
in
the
tilled
continuous
cropping
plots.
A
lower
incidence
of
tan
spot
was
noted
in
the
wheat
grown
on
summer
fallow.
Despite
herbicide
use,
kochia
and
Russian
thistle
were
evident
in
the
plots.
The
infestation
level
was
less
in
the
no-till
and
fallow
plots
than
the
tilled
plots.
Damage
by
rodents
was
not
observed
although
mice
activity
was
evident
within
the
tall
wheatgrass
barriers
themselves.
Grasshoppers
were
a
problem
in
the
spring.
Control
was
achieved
with
an
aerial
application
of
Sevin-XLR
on
June
5,
1988.
A
15-year
summary
of
the
data
obtained
from
the
barrier
system
from
1974-1988
is
reported
below:
Snow
Moisture
Collection
System
Plant
Height
Inches
Grain
Protein
Percent
Grain
Test
Wt
Lbs/Bu.
Grain
Yield
Bu/Acre
(-1
60
Ft.
Barriers
1974
20.7
15.6
60.0
18.1
1975
26.3
16.2
58.8
26.4
r.
-'^976
30.0
—
62.0
32.9
1977
16.4
15.7
60.3
4.9
1978
30.7
13.8
61.3
31.4
1979
21.7
15.0
61.0
15.4
"
1)80
10.8
14.6
57.3
11.2
1V81
—
16.0
58.2
18.7
1982
26.0
14.3
58.1
28.7
m
1983
25.4
16.6
60.6
20.9
1984
21.3
15.4
59.7
11.6
1988
11.7
16.5
56.6
11.9
«
1986
1987
26.8
12.1
61.8
24.2
20.8
15.2
60.5
23.7
1988
—
—
—
0.0
^
Average
22.2
15.2
59.7
18.7
(continued
on
next
page)
^:Z
S::-
-vv
Ho
inture
Collection
Svstem
Plant
Height
Inches
Grain
Protein
Percent
Grain
Test
Wt,
Lbs/Bu.
Grain
Yield
Bu/Acre
Open
Field
Stubble
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
Average
20.0
25.0
28.0
15.3
30.7
22.3
10.8
26.0
26.5
21.0
11.0
25.5
20.5
21.7
15.2
16.1
16.4
14.0
15.3
16.7
14.9
14.9
16.9
16.4
16.4
12.4
16.7
15.6
60.
G
59.5
62.5
60.3
61.0
60.3
57.8
58.0
57.5
60.5
58.4
56.4
61.3
59.8
59.5
26.0
30.4
40.3
4.2
37.6
19.6
3.9
19.8
27.6
24.3
10.0
10.9
24.7
26.0
0.0
20.4
Sunmier
Fallow
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
Average
21.0
28.0
32.0
19.5
32.5
23.4
12.0
26.0
28.0
21.0
18.0
28.0
23.0
13.0
23.2
16.9
16.4
16.2
14.5
16.7
15.6
17.1
15.6
16.6
17.3
16.9
13.2
15.0
18.4
16.2
58.5
59.0
61.0
59.5
60.5
61.0
59.0
59.5
57.0
60.0
58.1
56.3
60.9
59.5
57.5
59.2
45.4
35.3
62.5
18.5
54.7
24.9
23.0
23.4
32.9
26.0
22.9
12.0
38.9
36.0
3.7
30.7
During
the
last
15-year
period
of
this
continuous
cropped
spring
wheat
study,
grain
test
weights
have
averaged
0.4
lbs.
per
bushel
higher
under
continuous
cropping
within
the
barrier
systems
than
test
weights
on
fallow
and
0.2
lbs.
per
bushel
higher
on
continuous
cropping
in
open
field
stubble
than
on
fallow.
Conversely,
grain
protein
content
has
averaged
0.8%
higher
on
summer
fallow
than
on
continuous
cropping
within
the
barrier
system
and
0.4%
higher
grain
protein
on
summer
fallow
than
open
field
continuous
cropping.
Adjusted
average
yields
for
continuous
crop
spring
wheat
in
the
60
ft.
barriers
is
18.7
compared
to
20.4
bushels
per
acre
for
open
field
continuous
cropped
spring
wheat
and
30.7
bushels
per
acre
for
summer
fallow.
^3
None
of
the
barrier
plots
equal
open
field
continuous
cropping
as
to
crop
yield.
A
part
of
the
yield
difference
is
due
to
the
land
removed
from
wheat
production
^
by
the
presence
of
the
barriers
as
this
land
area
is
included
in
the
plot
size
for
yield
determinations.
The
competitive
effect
of
the
tall
wheatgrass
in
the
barriers
with
nearby
wheat
plants
also
causes
some
yield
reduction.
^
Tall
wheatgrass
barriers
do
provide
other
benefits
such
as
reduced
wind
erosion
and
favorable
climatic
effects
within
the
barriers.
None
of
the
continuous
cropping
plots
approach
summer
fallow
as
to
crop
yield
in
any
given
year,
p-f
However,
open
field
continuous
cropping
has
averaged
5.1
more
bushels
per
acre
per
year
than
the
wheat-fallow
rotation.
Continuous
cropping
in
the
tall
wheatgrass
barriers
system
has
produced
3.4
bushels
per
acre
per
year
more
than
the
wheat-fallow
rotation.
No-till
treatments
were
added
to
the
tall
wheatgrass
barriers
study
in
1977
for
comparison
with
conventional
till
and
plant
plots.
The
no-till
seeding
has
pro-
duced
yields
similar
to
the
tilled
and
planted
plots.
The
incidence
of
the
disease
Pyrenophora
trichostoma
(tan
spot),
has
been
greater
in
the
no-till
plots.
Conversely,
the
incidence
of
annual
weeds
such
as
wild
oats,
green
fox-
pn
tail,
and
yellow
foxtail
has
been
greater
in
the
till
and
plant
plots.
Volunteer
tall
wheatgrass
has
been
an
annual
problem
in
all
the
barrier
plots
each
spring,
necessitating
an
application
of
Roundup
herbicide
to
destroy
the
volunteer
wheat-
grass
prior
to
seeding.
This
treatment
is
also
effective
in
controlling
annual
"
weeds
that
have
emerged
in
the
no-till
plots.
FUTURE
PLANS:
Considering
the
cost
of
inputs
in
this
study
versus
the
present
f-*
price
and
supply
of
wheat,
the
continuous
cropping
of
spring
wheat
would
not
be
economically
feasible.
These
results
apply
only
to
the
continuous
cropping
of
spring
wheat.
If
the
land
were
also
cropped
to
winter
wheat,
safflower,
or
^
barley
in
a
flexible
cropping
system
with
spring
wheat,
the
result
might
likely
be
different.
One
of
the
long
term
objectives
of
this
study
is
to
develop
the
most
successful
methods
of
continuous
cropping
with
spring
wheat
regardless
of
economic
factors.
Economic
factors
and
demand
may
change
rapidly
and
drasti-
"
cally.
If
the
need
for
the
continuous
cropping
of
wheat
arises,
we
need
to
be
ready
with
the
proper
technology
to
permit
farmers
to
shift
to
continuous
crop
production
successfully.
This
may
require
a
special
means
of
moisture
conser-
^
vation
such
as
tall
wheatgrass
barriers
as
well
as
new
fertilizer
practices,
crop
varieties,
weed
control
methods,
disease
control
methods,
reduced
tillage,
and
new
types
of
farm
equipment.
Another
objective
of
this
study
is
to
deter
mine
the
long
term
influences
of
no-till,
conventional
till,
and
continuous
^
cropping
on
spring
wheat
growth,
vigor,
yield,
quality,
and
other
crop
perform
ance
characteristics.
Continuation
of
this
long
term
study
could
include
de
tailed
soils
analyses
to
detemine
the
long
term
influences
of
no-till,
conven-
^
tional
till,
and
continuous
cropping
on
soil
organic
matter,
soil
nutrients,
etc.
