Diversification of
Crested Wheatgrass
Stands in Utah
April Hulet, Bruce Roundy,
Brad Jessop & Jen Coleman
Brigham Young University
Why diversify Crested
Wheatgrass stands in Utah?
• >10 million hectares
• Highly competitive
• Longevity
• Loss of biodiversity
Background
1998-1999 Study “Increasing Native Diversity of
Cheatgrass Dominated Rangelands Through Assisted
Succession” Cox and Anderson; JRM 2004, 57:203-210
Question: Will native species establish better in a
perennial or annual monoculture?
Answer: It is easier to establish native vegetation in a
perennial monoculture.
Background
Assisted Succession Steps:
1. “Capture” the site with crested wheatgrass
2. Reduce crested wheatgrass (mechanical or herbicide)
3. Reseed the site with natives
Goals & Objectives
To determine effective ways to diversify
crested wheatgrass seedings while
minimizing weed invasion.
1. What treatment best controls crested wheatgrass?
2. How does wheatgrass control followed by native
revegetation affect weed invasion?
3. How do wheatgrass control methods affect native
plant revegetation success?
Goals & Objectives
THE HOPE:
Goals & Objectives
THE FEAR:
Site
Location
Salt Lake City
Skull Valley
Lookout Pass
Site Location
Skull Valley
Lookout Pass
Site Description
Skull Valley
• 1525m (5000’)
• 200 – 254mm (8 – 10”)
• Medburn fine sandy loam
• Wyoming big sage, Bluebunch wheatgrass,
Douglas rabbitbrush, Indian ricegrass
Lookout Pass
• 1676m (5500’)
• 254 – 305mm (10 – 12”)
•Taylorsflat loam
• Wyoming big sage, Bluebunch wheatgrass
30
30
Year 2
140
FCM-S
FCM-US
PCH-S
PCH-US
FCH-S
FCH-US
UD-US
UD-S
PCM-US
PCM-S
140
Year 1
140
PCM-US
PCM-S
FCM-S
FCM-US
UD-US
UD-S
FCH-S
FCH-US
FCH-S
FCH-US
140
BLOCK 1
30
30
Year 1
140
FCM-S
FCM-US
PCM-US
PCM-S
FCH-S
FCH-US
PCH-S
PCH-US
UD-US
UD-S
140
Year 2
140
PCH-US
PCH-S
FCH-S
FCH-US
PCM-US
PCM-S
UD-S
UD-US
FCM-S
FCM-US
140
BLOCK 2
30
30
Year 1
140
PCM-US
PCM-S
FCM-S
FCM-US
UD-US
UD-S
FCH-S
FCH-US
PCH-US
PCH-S
140
Year 2
140
FCM-S
FCM-US
PCH-S
PCH-US
FCH-S
FCH-US
UD-US
UD-S
PCM-US
PCM-S
140
BLOCK 3
30
30
Year 2
140
FCM-S
FCM-US
PCH-S
PCH-US
FCH-S
FCH-US
UD-US
UD-S
PCM-US
PCM-S
140
Year 1
140
FCM-S
FCM-US
PCM-US
PCM-S
FCH-S
FCH-US
PCH-S
PCH-US
UD-US
UD-S
140
BLOCK 4
30
30
Year 1
140
UD-US
UD-S
PCM-S
PCM-US
FCH-US
FCH-S
PCH-US
PCH-S
FCM-S
FCM-US
140
Year 2
140
PCH-US
PCH-S
FCH-S
FCH-US
PCM-US
PCM-S
UD-S
UD-US
FCM-S
FCM-US
140
155
155
155
155
155
155
155
155
155
155
BLOCK 5
30
30
30
Randomize Block
Split Plot Design
Main Plot: 1 acre (0.4 ha)
30
Sub Plot: ½ acre (0.2 ha)
PCM = 1-way disk
S = Seeded
Blocks = 5
FCM = 2-way disk
US = Unseeded
Year 1 = 2005
PCH = 16 oz/ac Roundup Original Max
Year 2 = 2006
FCH = 44 oz/ac Roundup Original Max
UD = Undisturbed (no treatment)
Timeline
2005
2006
2007
May – Sprayed
herbicide
(Year 1)
May – Sprayed
herbicide
(Year 2)
June – Collect Data
(Years 1 & 2)
June – Disked
(Year 1)
June – Disked
(Year 2)
June – Collected Data
(Year 1)
October – Seeded plots October – Seeded plots
(Year 1)
(Year 2)
Drill Configuration
Truax Rough Rider
Drill M
ix
Broa
dcas
t Mi
x
Drill Configuration
Drill Configuration
Drill Configuration
Drill Configuration
Seed Mix
PLS
kg/ha
Drilled Species
Bluebunch wheatgrass - 'Anatone'
3.36
3.54
Squirreltail - 'Sanpete'
2.24
3.16
Indian ricegrass - 'Nezpar'
2.24
2.39
Fourwing saltbush
1.12
3.90
Lewis flax - 'Appar'
0.84
0.93
Munroe globemallow
0.56
0.94
10.36
14.86
Sandberg bluegrass
0.84
1.06
White stemmed rabbitbrush
0.28
0.84
Wyoming big sagebrush
0.22
1.05
Yarrow - 'Eagle'
0.22
0.27
1.56
3.22
Total
Broadcast
Bulk
kg/ha
Total
Seed Mix
PLS
kg/ha
Drilled Species
Bluebunch wheatgrass - 'Anatone'
3.36
3.54
Squirreltail - 'Sanpete'
2.24
3.16
Indian ricegrass - 'Nezpar'
2.24
2.39
Fourwing saltbush
1.12
3.90
Lewis flax - 'Appar'
0.84
0.93
Munroe globemallow
0.56
0.94
10.36
14.86
Sandberg bluegrass
0.84
1.06
White stemmed rabbitbrush
0.28
0.84
Wyoming big sagebrush
0.22
1.05
Yarrow - 'Eagle'
0.22
0.27
1.56
3.22
Total
Broadcast
Bulk
kg/ha
Total
Seed Mix
PLS
kg/ha
Drilled Species
Bluebunch wheatgrass - 'Anatone'
3.36
3.54
Squirreltail - 'Sanpete'
2.24
3.16
Indian ricegrass - 'Nezpar'
2.24
2.39
Fourwing saltbush
1.12
3.90
Lewis flax - 'Appar'
0.84
0.93
Munroe globemallow
0.56
0.94
10.36
14.86
Sandberg bluegrass
0.84
1.06
White stemmed rabbitbrush
0.28
0.84
Wyoming big sagebrush
0.22
1.05
Yarrow - 'Eagle'
0.22
0.27
1.56
3.22
Total
Broadcast
Bulk
kg/ha
Total
Sampling Methods
5 transects X 6 quadrats = 30 samples per subplot treatment
Total of 1500 samples per site
Sampling Methods
5 transects X 6 quadrats = 30 samples per subplot treatment
0.25 m2 quadrat
Total of 1500 samples per site
• Density: all species
• Modified Duabenmire Cover
class: crested wheatgrass,
cheatgrass, Sandberg bluegrass
Cover
Class
Cover
Midpoints
1
0-1%
0.5
2
1-5%
3
3
5-15%
10
4
15-25%
20
5
25-50%
37.5
6
50-75%
62.5
7
75-95%
85
8
95-100%
97.5
Sampling Methods
5 transects X 6 quadrats = 30 samples per subplot treatment
0.25 m2 quadrat
Total of 1500 samples per site
• Density: all species
• Modified Duabenmire Cover
class: crested wheatgrass,
cheatgrass, Sandberg bluegrass
• Nested Frequency: cheatgrass,
crested wheatgrass seedling
5
11.2
25
35
50cm
Sampling Methods
5 transects X 6 quadrats = 30 samples per subplot treatment
0.25 m2 quadrat
Total of 1500 samples per site
• Density: all species
• Modified Duabenmire Cover
class: crested wheatgrass,
cheatgrass, Sandberg bluegrass
• Nested Frequency: cheatgrass,
crested wheatgrass seedling
Seedbank Bioassay
P < 0.05
Results
1. What treatment best controls crested wheatgrass?
Mature Crested Wheatgrass Cover
18
A
16
14
AB
A
AB
B
Cover (%)
12
10
BC
8
6
C
C
C
C
4
2
0
PCH
FCH
PCM
FCM
Lookout Pass
Lookout Pass
UD
PCH
FCH
PCM
FCM
Skull Valley
Skull Valley
UD
Results
1. What treatment best controls crested wheatgrass?
Mature Crested Wheatgrass Cover
18
A
16
14
AB
A
AB
B
Cover (%)
12
10
BC
8
6
C
C
C
C
4
2
0
PCH
FCH
PCM
FCM
Lookout Pass
Lookout Pass
UD
PCH
FCH
PCM
FCM
Skull Valley
Skull Valley
UD
Results
1. What treatment best controls crested wheatgrass?
Mature Crested Wheatgrass Density
16
A
A
14
12
2
Plants (m )
A
A
A
A
A
AB
10
BC
8
C
6
4
2
0
PCH FCH PCM FCM
Lookout Pass
UD
PCH FCH PCM FCM
Skull Valley
UD
Results
1. What treatment best controls crested wheatgrass?
Mature Crested Wheatgrass Density
16
A
A
14
12
2
Plants (m )
A
A
A
A
A
AB
10
BC
8
C
6
4
2
0
PCH FCH PCM FCM
Lookout Pass
UD
PCH FCH PCM FCM
Skull Valley
UD
Results
1. What treatment best controls crested wheatgrass?
Crested Seedling Density
8
A
7
A
AB
2
D ensity (m )
6
5
B
AB
A
A
A
AB
4
A
3
2
1
0
PCH FCH PCM FCM UD
Lookout Pass
PCH FCH PCM FCM UD
Skull Valley
Results
1. What treatment best controls crested wheatgrass?
Roundup Original Max
PCH – 1.1 L/ha
FCH – 3.2 L/ha
Results
1. What treatment best controls crested wheatgrass?
PCM – 1 way disk
FCM – 2 way disk
Results
2. How does wheatgrass control followed by native
revegetation affect weed invasion?
Lookout Pass:
Annual Weed Density
45
A
40
A
AB
30
2
Plants (m )
35
80% alyssum
11% cheatgrass
9% tumblemustard
25
Skull Valley:
20
10
5
92% cheatgrass
7% Russian thistle
0.5% tumblemustard
<0.1% alyssum
AB
15
A
A
A
PCM
FCM
UD
A
B
A
0
PCH
FCH
Lookout Pass
PCH
Lookout Pass
FCH
PCM
FCM
Skull Valley
UD
Results
2. How does wheatgrass control followed by native
revegetation affect weed invasion?
Lookout Pass:
Annual Weed Density
45
A
40
A
AB
30
2
Plants (m )
35
80% alyssum
11% cheatgrass
9% tumblemustard
25
Skull Valley:
20
10
5
92% cheatgrass
7% Russian thistle
0.5% tumblemustard
<0.1% alyssum
AB
15
A
A
A
PCM
FCM
UD
A
B
A
0
PCH
FCH
Lookout Pass
PCH
Lookout Pass
FCH
PCM
FCM
Skull Valley
UD
Results
3. How do wheatgrass control methods affect native
plant revegetation success?
Total Seeded per Treatment
35
A
30
Seedlings (m 2)
25
A
A
A
A
A
20
A
15
A
A
A
10
5
0
PCH
FCH
PCM
Lookout
FCM
UD
Lookout Pass
Pass
PCH
FCH
Skull
ValleyUD
PCM FCM
Skull Valley
Results
3. How do wheatgrass control methods affect native
plant revegetation success?
Total Seeded
30
A
20
B
Seeded species
15
10
25
5
20
A
2
0
Seedling (m )
2
Seedling (m )
25
Lookout1
Pass
Skull
Valley
15
B
10
A
B
5
A
0
A
LP SV
LP 1 SV
LP SV
Total Grass
Total Forbs
Total Shrubs
Results
3. How do wheatgrass control methods affect native
plant revegetation success?
Results
Precipitation Data:
Precipitation 2005-2006
80
Precipitation (mm)
70
60
50
40
30
20
10
Skull Valley
Au
gu
s
t
Ju
ly
Ju
ne
ay
M
Ap
ril
ar
ch
M
t
Se
pt
em
be
r
O
ct
ob
er
No
ve
m
be
r
De
ce
m
be
r
Ja
nu
ar
y
Fe
br
ua
ry
Au
gu
s
Ju
ly
Ju
ne
M
ay
0
Lookout Pass
Time of available water (days)
20
30
40
50
60
70
80
0
5
• Top: 1-3 cm
• Middle: 13-15 cm
• Bottom: 28-30 cm
Depth (cm)
10
15
>30 day
difference
20
25
30
35
Skull Valley
Lookout Pass
90
100
110
120
Summary
• Mechanical treatments best controlled crested
wheatgrass
• There were significantly less weeds in the herbicide
treatments than the mechanical treatments at Skull
Valley
• Treatments had no affect on seedling emergence
In June we will collect data on
1st and 2nd year plots
• Grasses had good emergence, but how many will
survive?
• What is the response to the 2nd year treatments?
TIME WILL TELL…