Author
 |
SEEFELDT, STEVEN |
|
Submitted to: Meeting Abstract
Publication Type: Abstract Only Publication Acceptance Date: 8/22/2008 Publication Date: N/A Citation: N/A Interpretive Summary: In Interior Alaska, land that is in the Conservation Reserve Program and roadside rights-of way must be kept relatively free of woody plant species. Mowing every 2 to 3 years is the standard practice, but it has become less effective. Therefore alternative methods for managing these plant species need to be developed. A new application technology, the wet-blade mower, which pumps herbicide out to the mower blades where it coats the cut surface of plants, may provide land managers a cost-effective way to use herbicides to control these woody species while not killing lower growing desirable broadleaf plants. This study compared the wet-blade mower to normal broadcast applications and traditional mowing for shrub control and impact on desirable plant species. Two herbicides were tested, 2,4-D and Garlon. The study was conducted on several fields and roadsides. Treatments were applied on July 2006 and 2007 and plant cover was measured before and 1 yr after herbicide application. In the 2006 treatments, Garlon was better than 2,4-D at reducing shrub species and broadcast application was slightly better than the wet-blade for reducing shrub species the first year but over all control was not acceptable. In the 2007 treatments shrub mortality of all treatments was over 90%. Treatment failure the first year was due to a hard freeze in June that stopped shrub growth, resulting in limited uptake and translocation of the herbicides. In low density shrub stands, low growing forb species in the wet-blade treatments were partially controlled, an indication that the herbicides were not sticking to the blades. Greenhouse and field research results indicate that aminopyralid may provide excellent long term control or orange hawkweed with little impact on native grasses. Technical Abstract: Mowing every 2 to 3 yr is not controlling woody plant species on Interior Alaska Conservation Reserve Program lands, therefore alternative methods for managing these plant species need to be developed. A new application technology, the wet-blade mower, which pumps herbicide out to the mower blades where it coats the cut surface of plants, may provide growers with a cost-effective way to use herbicides to control these woody species while minimizing off target impacts. The objectives of this research were to: compare efficacy of the wet-blade mower, a broadcast application, and traditional mowing; compare off-target impacts of the wet-blade mower and broadcast application; and compare 2,4-D and triclopyr for efficacy on woody vegetation and off-target plant species. The study was conducted on several fields and roadsides using a randomized complete block experimental design. On each field there were four blocks with seven treatments applied in July 2006 and 2007. Amine formulations of 2,4-D (2.2 kg/ha) and triclopyr (1.7 kg/ha) were used with the wet-blade mower and ester formulations of 2,-4-D and triclopyr (both 2.2 kg/ha) were broadcast with a 15 m boom. Mow treatments were cuts at 38 or 15 cm. Wet-blade treatments were applied with a 38 cm high cut to provide a physical separation of the herbicide from off-target plants and farmers typically cut at 15 cm. Plots were 18x 60 m and plant cover was measured before and 1 yr after herbicide application. In the 2006 treatments, Garlon was better than 2,4-D at reducing shrub species and broadcast application was slightly better than the wet-blade for reducing shrub species the first year but over all control was not acceptable. In the 2007 treatments shrub mortality of all treatments was over 90%. Off-target impacts were similar for both broadcast and wet-blade applications. The impact of the wet-blade mower on low growing desirable forbs is an indication that the herbicides were not sticking to the blades. An experiment started in 2007 will determine if lowering the application height of the wet-blade mower to 15 cm will improve control of woody species as translocation distance to roots will be reduced. Greenhouse and field research results indicate that aminopyralid may provide excellent long term control or orange hawkweed with little impact on native grasses. In tow greenhouse and field trials, set up in randomized complete block experimental designs with multiple rates of triclopyr, clopyralid, and aminopyralid, the aminopyralid formulation resulted in excellent control of orange hawkweed and both full and half herbicide label rates with minimal effects on native grasses. |
