Integrated Management Strategies Reduced Tall Ironweed (Vernonia altissima) Populations and Weed Biomass and Improved Tall Fescue Pasture Productivity

Abstract

Field studies were used to examine the management strategies of mowing, herbicide, fertility, and all possible combinations on tall ironweed populations, weed biomass, and pasture yield at three Kentucky locations. Mowing was performed in July 2008 and 2009, herbicide was applied in August 2008, and fertilizer was applied in September 2008 and 2009 at all locations. Weed populations were measured in 2008, 2009, and 2010, and forage grass, clover, and weed biomass was collected in May or early June of 2009 and 2010. All treatments with herbicide reduced tall ironweed stems by 64% or greater in 2009 at all locations. Mowing alone, fertilizer alone, and mowing plus fertilizer did not reduce tall ironweed populations, except at one location where mowing alone reduced tall ironweed stems by 64% in 2009. Tall ironweed stems were not reduced in 2010 with any treatment at two locations, but herbicide combined with mowing or fertilizer reduced tall ironweed stems by 78% at the other location. Tall goldenrod population was reduced up to 100% by all treatments with herbicide or mowing alone, and mowing with fertilizer reduced tall goldenrod from 59 to 89%. Treatments did not reduce horsenettle populations. Herbicide-containing treatments reduced weed biomass at all locations. Weed biomass did not differ when comparing all treatments with and without mowing or treatments with or without fertilizer. Forage grass biomass was greatest with herbicide plus fertilizer and with the combination of mowing plus herbicide plus fertilizer at all locations in both years.

Solanum carolinense L.

“…In pastures, S. carolinense is considered as a drought‐resistant competitor and is presumed to reduce the yield and quality of forage crops (Beeler et al, 1994). For example, population density of S. carolinense on an experimental site averaged 86 stems in 10 m 2 in a tall fescue dominated pasture (Richmond/USA; Tolson et al, 2012). Pasture weeds, such as S. carolinense , reduce desirable forage biomass through direct competition for resources or displacement of valuable forage species.…”

Stocking method and monensin supplementation effects on cow and calf performance and pasture productivity

“…Using stocking intensity as weed control has been well established by Harker et al (2000) when they demonstrated a reduction in weed prevalence in intensely stocked pastures without herbicide and Average N concentration of weeds was greater (2.71%; p < .01) than average N concentration of crops (2.23%, data not shown). This was not surprising because pasture weeds are high N accumulators that directly compete for resources which can reduce the growth of desirable forages (Harper et al, 1933;Tolson et al, 2012). Levels of high N stimulate competitive weed species to produce biomass quickly and early on, thus outcompeting crops.…”

Utility of Aminocyclopyrachlor for Control of Horsenettle (Solanum carolinense) and Tall Ironweed (Vernonia gigantea) in Cool-Season Grass Pastures

“…In a Missouri study, 70 g ha À1 aminopyralid applied in May or August reduced stem density 73 to 75% the following season (Payne et al 2010). Tolson et al (2012) reported 66 to 89% reduction in tall ironweed stems at 1 yr after August application of aminopyralid plus 2,4-D at 115 þ 1,000 g ha À1 .…”

“…Management of many perennial pasture weeds has been a challenge with traditional pasture herbicides, clipping, or grazing. This is due to their tolerance of herbicides, their capacity to store ample carbohydrates in rhizomes and roots, and the fact that most grazing animals avoid them (Albert 1960;Gorrell et al 1981;Ilnicki and Fertig 1962;Marshall et al 2006;McCarty and Linscott 1963;Peters and Lowance 1978;Tolson et al 2012). Another study found that clipping reduced tall ironweed biomass, but had no positive long-term effect on weed population (Tolson et al 2012).…”