Grassland Restoration Project – Background Information
Sometime prior to 1993, Schnell Ranch had converted 700 acres of native prairie to hayland seeded with smooth bromegrass, crested wheatgrass, and Kentucky bluegrass. These perennial tame grasses were hayed and/or grazed on a regular basis during the commercial operation of the Ranch. In addition to utilizing perennial tame grasses, the Ranch grazed native pastures. Since ownership and usage of the Schnell Ranch changed in 1993, haying has occurred infrequently and grazing not at all. As a result the introduction of tame grasses by the previous owners and the post 1993 management system, cool season perennial tame grasses have invaded adjacent native pastures and other areas not previously seeded to tame grass. Proper grazing management designed to imitate evolutionary relationships between animals and native plants over time where native grass and forbs are present in tame species infested pastures can bring back the native plant community to a state it was prior to the tame plant invasion. The Dickinson Research Extension Center currently has a memorandum of understanding with the Bureau of Land Management to provide cattle and management to graze specific areas of the Schnell Ranch Recreation Area.
Where native prairie was converted to tame grass hayland/pasture some time ago through tillage, few actively growing native plants were found and the native seed bank was likely to contain few viable seed capable of germinating and establishing if competitive tame species were removed through grazing. Grazing alone on these disturbed tame pastures is not likely to bring about the desirable outcome stated by the Bureau of Land Management in the Native Grassland Restoration Project. Burning has been used successfully in some restoration projects but at the Schnell Ranch location, burning alone is not likely to reduce or eliminate tame species since the burn would not likely be intense enough to kill the cool season tame grass species present. In fact burning, a process used by grass seed producers in the Pacific Northwest, may actually stimulate seed production in Kentucky bluegrass.
No-till methods are used to reestablish native grasses on 300 of a 700-acre area identified by the Bureau of Land Management as having been tilled and tame grasses seeded for the purposes of producing hay by the previous owners. No-till methods include the termination of existing vegetation with herbicides followed by directly seeding into the killed sod with a low-disturbance no-till drill. Herbicide termination methods used in previous restorations by the NRCS (Anonymous, 2002; Tober, 2006) used glyphosate at 1.0 lbs a.i. per application in two or three sequential treatments during the growing season. This termination method requires a full season for termination prior to seeding as well as varying degrees of success in reduction and termination of established smooth bromegrass, crested wheat grass, and Kentucky bluegrass. The frequency of these grasses remaining after herbicide termination and no-till seeding of native grasses varied from 0% to 70%.
This project will demonstrate and allow participants to compare three termination methods using glyphosate (Honcho Plus in this case) herbicide. Success in termination techniques will have direct impact on the success of the establishment of native species with a low-disturbance no-till drill. Termination Methods #1 and #2 commenced on June 3, 2007 and termination Method #3 occurred on June 2, 2009.
Termination Method #1 was applied to a total of approximately 25 acres found within field boundaries A plus B (see Google Earth tour of project). This method was described by NRCS in their Native Prairie Restoration Study Final Report, 1998-2002. This termination method required three sequential applications of 1 pound of glyphosate per acre per application. During the last termination application, 0.5 pounds acid equivalent per acre of 2,4-D amine was included for hard to control fall emerged broadleaf weeds.
The second termination method (Method #2) was similar to Method #1 except ammonium sulfate (AMS) was included to increase herbicidal activity. Termination Method #2 applied to 25 acres found within field boundary C. Both Methods #1 and #2 required applications occur the season prior to seeding. Seeding of areas treated with termination Methods #1 and #2 (field A, B, & C) began on May 22, 2008 and was completed by June 1, 2008 using a Cross-Slot™ opener equipped drill. Precipitation events were tracked using a RainWise™ self tipping rain bucket and Hobo™ pendant event/rainfall/temperature data logger.
Termination Method #3 was not initiated in 2008 since precipitation received the six months prior to the scheduled termination date was well below normal. Plant stress was high and foliar development of domesticated species was low so expectations for herbicide performance for termination at that point would have been very poor and incomplete.
Termination Method #3 uses a one-time application of glyphosate, at the rate of 2.25 pounds of active ingredient per acre with the addition of 17 pounds of spray grade AMS per 100 gallons of spray solution. No additional herbicide applications have been applied to terminate cool season tame grasses except where the termination application failed due to untimely precipitation or skips between passes. Termination method #3 consists of approximately 50 acres found within field boundaries D, E, F, G, and H. Due to poor weather conditions the herbicide application did not begin until June 2 and was not completed until June 12, 2009. Rainfall shortly after the late afternoon termination application in field E on June 2 likely caused failure of the initial application before the herbicide was fully translocated into the targeted species. This required an additional application of glyphosate which was made on June 29 after the area was seeded but prior to emergence of desired grass and forbs.
Seeding began on June 19, 2009 and continued until July 1, 2009. The same drill that was used in 2008 to seed areas terminated by Methods #1 and #2 was used to seed areas terminated with Method #3 in 2009.
If Method #3 works as expected the termination and establishment period can be shorten by at least a year as well as reduced herbicide costs. At the time this was updated native grass and forbs was emerging with a few weeds present (August 21, 2009). Photos from August 21 can be viewed by clicking here.
If you have a questions about the project feel free to contact Roger Ashley.