Wildflower establishment after herbicide applications

Transcription

1 Wildflower establishment after herbicide applications Mark Renz 1, Mike Moechnig 2, and Mary Halstvedt 3 1 University of Wisconsin-Madison; 2 South Dakota State University; 3 Dow AgroSciences

2 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

3 Establishment of clover in pastures from frost seeding Untreated area Treated area (milestone)

4 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

5 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

6 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

7 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)

8 What herbicides did we spray? Active ingredients rates (lbs ae/a) Product rate aminopyralid Milestone 3 fl oz/a aminopyralid 0.11 Milestone 7 fl oz/a aminopyralid + metsulfuron aminopyralid + triclopyr aminopyralid + triclopyr aminopyralid + clopyralid Chaparral Capstone Capstone Milestone + Transline 3.3 oz/a 6pt/A 8pt/A fl oz/a clopyralid 0.21 Transline 9 fl oz/a clopyralid Transline 16 fl oz/a tebuthiuron 0.4 Spike 0.5 lbs/a

9 What species did we evaluate? Wisconsin Black-eyed susan Rudbeckia hirta Lance leaved coreopsis Coreopsis lanceolata Blanketflower Gaillardia pulchella Wild Bergamot Monarda fistulosa Smooth blue aster Aster laevis South Dakota Black eyed susan Rudbeckia hirta Lance leaved coreopsis Coreopsis lanceolata Blanketflower Gaillardia pulchella Wild Bergamot Monarda fistulosa New England aster Aster novae-angliae Yellow coneflower Ratibida pinnata Purple coneflower Echinacea purpurea Round headed bush clover Lespedeza capitata Prairie coneflower Echinacea pallida Purple prairie clover Dalea purpurea IL bundleflower Desmanthus illinoensis Canada milk-vetch Astragalus canadensis Golden alexander Zizia aurea

10 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)

11 Results were site and species specific 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 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

12 Plants per meter Effect of planting date on forbs 2 YAT Wisconsin fall spring Indicates difference between planting dates P<0.05

13 Plants per meter Effect of planting date on forbs 2 YAT South Dakota Fall Spring Indicates difference between planting dates P<0.05

14 Effect of herbicides on forbs 2 YAT Wisconsin BE-susan LL coreopsis Y cone-flower Plants per meter Mile 3 fl oz/a Mile 7 fl oz/a Chap 3.3 oz/a Capstone 6pt/A Capstone 8pt/A Mile 3 + Tran 9 fl oz/a Transline 9 fl oz/a Transline 16 fl oz/a Spike 0.5 lbs/a UTC Indicates different than the UTC p<0.05; Red lower, green higher

15 Effect of herbicides on forbs 2 YAT Prairie CFlower South Dakota BEsusan Canada milkvetch Plants per meter Bergmot G Alex Mile 3 fl oz/a Mile 7 fl oz/a Chap 3.3 oz/a Capstone 6pt/A Capstone 8pt/A Mile 3 + Tran Transline 9 fl oz/a Transline 16 fl oz/a Spike 0.5 lbs/a UTC Indicates different than the UTC p<0.05; Red lower, green higher

16 Most plots looked like this

17 Not all:spike

18 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