Project Number: 5360-21630-001-08-R
Project Type: Reimbursable Cooperative Agreement
Start Date: Jan 10, 2014
End Date: May 30, 2014
1) Evaluate native and introduced seed mixes effectiveness for revegetating medusahead-invaded sagebrush rangelands and limiting medusahead reinvasion. 2) Determine which seed mix most limits plant available soil resources. 3) Determine if seeding can occur immediately after fall application of imazapic or if seeding should be delayed one year to limit non-target herbicide damage to seeded species. 4) Evaluate revegetation success and plant community diversity when seeding introduced and native species together after fall control of medusahead. 5) Determine the effectiveness of prescribed burning and various herbicides applied in the spring at controlling medusahead. 6) Determine the best spring applied treatment for promoting the establishment of seeded perennial grasses.
Experimental Design: Study 1: A randomized complete block design with five sites will be used to evaluate the effects of treatments on vegetation and soil characteristics. Each site consists of five 30 x 50 m plots randomly assigned to the different treatments with a 2-m buffer between treatments. This results in 25 plots (5 sites X 5 treatments = 25 plots). In 2010, three of the plots in at each site were fall prescribed burned and then treated with imazapic (Plateau®), used as a pre-emergence herbicide. In the fall of 2011, these plots were randomly assigned and seeded with a mix of introduced, native, or introduced-native species. In 2011, another plot at each site was fall prescribed burned and treated with imazapic. This plot was immediately seeded with an introduced species mix to determine if seeding can occur without waiting one growing season after applying imazapic. The fifth plot at each site will be the control (non-treated) plot. Study 2: A randomized complete block design with six sites will be used to evaluate different spring applied treatment to control medusahead and promote seeded perennial grasses. The following nine treatments will be randomly assigned to 7 X 7 m plots separated by a 1-m buffer at each site: prescribed spring burn, contact herbicide application, pre-emergent herbicide application, combination of spring burning and pre-emergent herbicide application, combination contact and pre-emergent herbicide application, untreated (control) that will be seeded, and a control that will not be seeded. This will result in 54 plots (9 treatments X 6 sites = 54 plots). All treated plots will be seeded in the fall with a mixture containing crested wheatgrass and native perennial grasses.