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The Use of Herbicides to Rehabilitate Native Grasslands. Thomas G. Barnes Extension Professor Department of Forestry. Globally Rare System Less than 4% of original 81 million ha remain 64% of rare communities In KY are grass dominated. OBJECTIVES.
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The Use of Herbicides to Rehabilitate Native Grasslands Thomas G. Barnes Extension Professor Department of Forestry
Globally Rare System Less than 4% of original 81 million ha remain 64% of rare communities In KY are grass dominated
OBJECTIVES 1. Efficacy of 3 herbicides for removing tall fescue from native grasslands & releasing NWSG 2. Document post-emergence forb tolerance to imazapic & sulfosufuron
Methods • 14 study sites • 6 in Outer Bluegrass (Scott, Bullitt, Lewis) • 2 in Cumberland Plateau (Rowan, Whitley) • 6 in Mississippi Plateau (Hart, Hardin, Grayson)
Methods • Pre-treatment vegetative communities • 50% fescue & 50% natives • NWSG varied by site (big bluestem, Indiangrass, little bluestem, switchgrass, broomsedge, Elliott’s broomsedge, split-beard broomsedge, tall dropseed) • Variety of soils (mostly limestone) • Variety of forbs
Methods • 3 Herbicides 12 oz Plateau (+ MSO) 12 oz Select (+ MSO) – graminicide 2 oz Outrider (+ MSO) • Plot size 3 x 10m • Applied April with CO2 pressurized backpack sprayer • Walk 1 kph delivering volume 187 L/ha • Temp varied 13 – 28C, relative humidity averaged 60%, winds < 16 kph
Methods Vegetative Samples 3 .3m2 per treatment plot Total vegetative cover % Fescue % NWSG % Bare Ground Species Richness PROC GLM, Least Mean Square
Total Vegetative CoverYear One b a a a
Total Vegetative CoverYear Two a a a a
Percent FescueYear One a b c c
Percent FescueYear Two b a a a
Percent NWSGYear One a b c c
Percent NWSGYear Two a a a b
Percent Bare GroundYear One b a,b c c
Percent Bare GroundYear Two b b b a
Species Richness b a,b c c
All three do good job after one year of taking out fescue, forb species do not vary much between herbicides Select Plateau Outrider
Plateau Tolerant Forbs • Mostly in Poaceae, Fabaceae, Asteraceae • Over 100 species
Plateau Tolerant Forbs • Eupatorium coelestinum, hyssopifolium, serotinum, fistulosum • Aster pilosus, dumosus, patens, ontarionensis, lateriflorus, novae-angliae • Solidago altissima, rugosa, odorata, nemoralis • Asclepias tuberosa, viridis, viridiflorus • Silphium terebinthenaceum, pinnatifidum • Rudbeckia hirta, fulgida, Ratibida pinnata, Helianthus divaricatus, H. atrorubens
Exercise Caution • Invasive exotic forbs, legumes • Crown vetch, sericea lespedeza, spotted knapweed, white & yellow sweet clover, Japanese honeysuckle
Mgmt Implications • All Three Herbicides are effective at removing tall fescue • Imazapic releases NWSG • Clethodim protects forbs • Sulfosulfuron good compromise (cheaper)