Wildflower establishment after herbicide applications
Mark Renz1, Mike Moechnig2, and Mary Halstvedt3 1University of Wisconsin-Madison; 2South Dakota State University; 3Dow AgroSciences
Why is this research important?
• Interest in restoring mixed forb grass prairies
• Invasive plants can reduce establishment
• BMPS recommend management prior to establishment, BUT
– Many herbicides can persist in the soil for months
– Has the potential to reduce establishment
Establishment of clover in pastures from frost seeding
Untreated area
Treated area (milestone)
Why study this?
• Tolerance of species to herbicides is highly variable and rate dependent
• Forb seed are expensive
• No data on tolerance of native forb species common to Midwestern US when applied before planting
Objectives of this study
• To determine if herbicide applications the summer before planting will reduce establishment of common forbs for mixed prairie plantings:
– Fall dormant seeding
– Spring seeding
Methods
• Conducted at Arlington WI, and Beresford, SD
• Split-plot with four replications – Planting method Main
plot
– Herbicide sub plot
• Herbicides applied in July 2009
Methods
• Forbs planted with No-till drill in rows – Fall 2008 (dormant)
–Oct. (WI) – Nov (SD) =3-4 months after treatment
– Spring 2009 – April = 9 months after treatment
• Forb density counted per row – June 2010 (1 YAT)
– October 2010 (1.5 YAT)
– July 2011 (2 YAT)
What herbicides did we spray? Active ingredients rates
(lbs ae/A) Product rate
aminopyralid 0.047 Milestone 3 fl oz/A
aminopyralid 0.11 Milestone 7 fl oz/A
aminopyralid + metsulfuron
0.11 +0.02
Chaparral 3.3 oz/A
aminopyralid + triclopyr
0.08 +0.75
Capstone 6pt/A
aminopyralid + triclopyr
0.11 +1.0
Capstone 8pt/A
aminopyralid + clopyralid
0.047 +0.21
Milestone + Transline
3 + 9 fl oz/A
clopyralid 0.21 Transline 9 fl oz/A
clopyralid 0.375 Transline 16 fl oz/A
tebuthiuron 0.4 Spike 0.5 lbs/A
What species did we evaluate?
Wisconsin South Dakota Black-eyed susan Rudbeckia hirta Black eyed susan Rudbeckia hirta
Lance leaved coreopsis Coreopsis lanceolata Lance leaved coreopsis Coreopsis lanceolata
Blanketflower Gaillardia pulchella Blanketflower Gaillardia pulchella
Wild Bergamot Monarda fistulosa Wild Bergamot Monarda fistulosa
Smooth blue aster Aster laevis New England aster Aster novae-angliae
Yellow coneflower Ratibida pinnata
Purple coneflower Echinacea purpurea Prairie coneflower Echinacea pallida
Round headed bush clover Lespedeza capitata Purple prairie clover Dalea purpurea
IL bundleflower Desmanthus illinoensis
Canada milk-vetch Astragalus canadensis
Golden alexander Zizia aurea
Analysis of plant density
• Analyzed each site and species within sites separately
• Analysis of Variance (ANOVA) for each sampling period • SAS PROC Mixed
• Means separation with LS means (p<0.05)
Species WI SD Planting Herbicide PxH
Black-eyed susan X X Varied by site Varied with time NS
Lance leaved coreopsis X X <0.01 Varied with time & site NS
Blanketflower X X <0.05 Varied with time NS
Wild Bergamot X X <0.01 Varied with time & site NS
Smooth blue aster X Varied with time NS NS
New England aster X NS NS NS
Yellow coneflower X Varied with time Varied with time NS
Purple coneflower X <0.01 NS NS
Prairie coneflower X Varied with time 0.01 0.04
R-headed bush clover X <0.01 NS NS
Purple prairie clover X <0.01 NS NS
IL bundleflower X <0.01 NS NS
Canada milk-vetch X <0.01 <0.01 NS
Golden alexander X X <0.01 Varied with time NS
Results were site and species specific
0
0.5
1
1.5
2
2.5
3
3.5
4
Pla
nts
per
met
er
fall
spring
Effect of planting date on forbs 2 YAT Wisconsin
* *
*
*
*
*
* Indicates difference between planting dates P<0.05
00.5
11.5
22.5
33.5
44.5
Pla
nts
per
met
er
Fall
Spring
Effect of planting date on forbs 2 YAT South Dakota
*
* *
*
*
* * *
* Indicates difference between planting dates P<0.05
Effect of herbicides on forbs 2 YAT Wisconsin
BE-susan LL coreopsis Y cone-flower
Plants per meter
Mile 3 fl oz/A 1.4 2.4 2.6
Mile 7 fl oz/A 1.3 2.4 2.3
Chap 3.3 oz/A 0.6* 1.9 1.5
Capstone 6pt/A 0.5* 2.1 3.2
Capstone 8pt/A 0.7* 1.5 2.5
Mile 3 + Tran 9 fl oz/A 1.2 1.8 2.2
Transline 9 fl oz/A 1.0 2.7 2.6
Transline 16 fl oz/A 0.4* 2.2 3.0
Spike 0.5 lbs/A 0.5* 0.6* 1.3
UTC 1.6 2.2 2.4
* Indicates different than the UTC p<0.05; Red lower, green higher
Prairie CFlower
BE-susan
Canada milkvetch
Bergmot G Alex
Plants per meter
Mile 3 fl oz/A 3.4* 3.1 1.5* 3.4* 0.9
Mile 7 fl oz/A 3.3* 2.8 1.3* 3.0* 0.6
Chap 3.3 oz/A 0.9 2.1 0.3 1.8 1.1
Capstone 6pt/A 2.6* 2.6 0.8 2.5 1.0
Capstone 8pt/A 3.1* 2.6 1.0 3.8* 1.3
Mile 3 + Tran 9 3.9* 3.4* 1.8* 2.9* 1.6*
Transline 9 fl oz/A 3.0* 2.5 1.0 3.1* 1.8*
Transline 16 fl oz/A 3.0* 3.4* 1.8* 3.9* 1.3
Spike 0.5 lbs/A 1.9 1.5 1.0 1.9 1.1
UTC 1.6 2.0 0.4 1.3 0.6 * Indicates different than the UTC p<0.05; Red lower, green higher
Effect of herbicides on forbs 2 YAT South Dakota
Most plots looked like this
Not all:Spike
Conclusions
• 86% forbs showed no differences or increased density from treatments when applied 3 months before planting.
– B-eyed susan sensitive to milestone, chaparral, & spike at one site
– Lance leaved coreopsis sensitive to spike
• Fall dormant or spring plantings had no effect on response to herbicides • Prairie coneflower was the one exception
• Results demonstrate: Herbicides can be used prior to planting forbs to control invasive plants
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