Evaluating Strategies
for Increasing Plant Diversity
in Crested Wheatgrass Seedings
[Elko County, NV]
Kent McAdoo, UNCE
John Swanson, UNR
Clare Poulsen, USDA - ARS
Brad Schultz, UNCE
Nancy Shaw, USFS
Assisted Succession
Where necessary, seed with
adapted “functional
equivalents” (Connelly et
al. 2000) then interseed
with native species.
Research Objectives
1 - Determine the effect of crested wheatgrass (Aropyron
desertorum) control methods on wheatgrass density
and cover.
2 - Determine the effect of crested wheatgrass control
methods and revegetation on establishment of native
seeded species.
Great Basin Native Plant
Selection & Increase Project
Companion studies in:
• Utah
• Oregon
• Idaho
• Nevada
Crested Wheatgrass Control
and Revegetation Treatments
The following strategies are being tested in a
randomized block, split-split plot design:
(1) untreated crested wheatgrass;
(2) partially controlled crested wheatgrass; and
(3) maximum crested wheatgrass controll.
The study site is comprised of 5 blocks.
Crested Wheatgrass Control
and Revegetation Treatments
•
•
•
•
Disking
Spring-applied glyphosate
Disking + spring-applied glyphosate
Spring- + fall-applied glyphosate
Each 1-acre treatment plot was divided into
seeded and unseeded sub-plots
Treatment Chronology
• During November 2007, “disked only plots” were
3-way disked.
• In May, 2008 “spring-applied herbicide plots”
and “combined disked and herbicide plots” were
sprayed with 66 oz. glyphosate/ac.
• In early October 2008, “combined spring- and
fall-applied herbicide plots” were sprayed with
66 oz. glyphosate/ac.
• In late October 2008, sub-plots were seeded by
personnel from the NRCS Aberdeen Plant
Materials Center with a Truax Rough Rider
rangeland drill.
Final seeding mix for South Fork study plots, Elko County,
NV, in sandy loam soil (8 inch precipitation zone)
Species
• Indian ricegrass
• Bottlebrush squirreltail
• Needle-and-thread grass
• Basin wildrye
• Bluebunch wheatgrass
• Sandberg bluegrass
• Munro globemallow
• Lewis flax
• Western yarrow
• Wyoming big sagebrush
• Spiny hopsage
Total
PLS pounds
2.0
2.0
2.0
2.0
1.0
0.75
0.5
0.75
0.2
0.2
0.5
11.9
October 2008
Summer 2009- Cover, density, and seedling
frequency
Preliminary Results
2009 Untreated
(Very little cheatgrass)
3X Disk Treatment (11/08)
2009 -No significant Agde Reduction (p>0.05)
May 2008 Glyphosate
2009 Significant Agde Reduction (p<0.05)
Spray 2X (spring & fall 2008)
2009 Significant Agde Reduction (p<0.05)
Untreated
Spray 2X (spring & fall)
Spray
Both Glyphosate Treatments
Reduced Crested WG (P<0.05)
Disk (11/07) + Spray (5/08)
Significant Crested WG Reduction (p<0.05)
Crested Wheatgrass Cover *
50
a
45
a
40
% Cover
35
30
43.9
25
41.0
20
15
b
6.1
10
b
4.5
b
4.5
5
0
Untreated
Disk
Spring Glyphosate
Spring & Fall Glyphosate
* means with differing letters are significantly different (p<0.05)
Disk & Glyphosate
Crested Wheatgrass Density*
b
7
6
a
Plants/m 2
5
6.1
4
c
4.7
c
c
3
2.9
2
2.5
2.8
1
0
Untreated
Disk
Spring Glyphosate
Spring & Fall
Glyphosate
Disk & Glyphosate
* means with differing letters are significantly different (p<0.05)
Seeded Species Establishment
(First (2009) Growing Season)
Future Plans
Additional plots
• Additional plots established in 2010 for comparisons
between years.
Analysis & Publication
• Data analyzed using mixed model analysis, with blocks
and years considered random and other treatments
considered fixed.
• Publish Manuscript