2013 Annual Report
1a.Objectives (from AD-416):
The ARS will use funding provided in this agreement to continue to restore and/or evaluate the success of rehabilitated areas within degraded Gardner Saltbush communities.
1b.Approach (from AD-416):
The ability to restore or rehabilitate degraded Gardner saltbrush communities with forage kochia, improved cool-saason grasses, and native plant materials will be evaluated. These communities are degraded due to invasion of halogeton (annual toxic plant), which results in increased soil salinity. The evaluation will be arranged in a replicated split-block design to evaluate the establishment, persistence, and competition of improved and native plant materials with halogeton. Soil prep treatments (aggressive tillage versus minimal disturbance) will be included to determine the best methods to establish plant materials in these sites. Aggressive tillage will be done with a deep disk or rototiller to remove existing halogeton and dilute soil surface salts; whereas minimal disturbance will include no-till drilling or light soil surface disturbance (e.g. harrow). Plant materials will include standard and improved lines of forage kochia, Russian wildrye, Siberian wheatgrass, and tall wheatgrass. Controls will include plots that are not reseeded, and plots seeded to plants native to the ecosystem including Gardner saltbrush and Indian ricegrass. In addition, strategic mixtures such as forage kochia and cool-season grasses mixed with Gardner saltbrush will be included. Plant monocultures and mixes will be established via seeding and transplanting. The transplanting will allow evaluation of survival and salt tolerance, assuming successful establishment.
This agreement was entered into to evaluate the success of rehabilitating degraded Gardner Saltbush communities using forage kochia to compete with the annual invasive halogeton.
During FY-2013: The Forest Service provided two fenced enclosures within degraded Gardner saltbrush ecosystems (Gardner saltbrucs had been totally replaced by halogeton). During the winter of 2011 and again 2012 seeding experiments were attempted but the following year appeared to have failed. The treatments consisted of Forage kochia, Gardner saltbrush, and grasses seeded into three soil treatments: disking the soil prior to seeding, adding compost prior to seeding, and direct seeding. During FY2013, we attempted to establish a third seeding by repeating the above treatments at 2x and 4x the regular seeding rate. Preliminary evaluations during the spring of 2013 revealed that the 4x rate has some success.
A second study was established in separate enclosures in 2011 and 2012, by transplanting seedlings of forage kochia, grasses, and Gardner saltbush. All entries and mixtures in the seeded study were included in the transplanted seedling study. All seedlings were started in January 2011 and grown in cone-tainers in the greenhouse until transplanted. Plots were 4 plants wide X 4 plants long. A late-frost killed or injured most of the transplants in the second (2012) enclosure. During 2013, a second year’s data on halogeton frequency was determined at 20, 30, 40, and 50 cm intervals in the interspaces between the 1-m spaced rows of plants.
The USDA-FS has been an excellent cooperator. They provided the sites and fenced enclosures in addition to research funds. No peer-reviewed manuscripts have come from this research yet; however, one M.S. level graduate student that is co-advised by the PI is assigned to this project.