2012 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.
During FY 2012: An experimental planting was reseeded during the fall and winter of 2011-12 inside two fenced exclosures within degraded Gardner saltbrush ecosystems. Gardner had been totally replaced by halogeton. Forage kochia, Gardner saltbrush, and grasses were seeded into three treatments: disking the soil prior to seeding, adding compost prior to seeding, and direct seeding. The entries included Immigrant and four experimental lines of forage kochia, Bozoisky-II Russian wildrye, Alkar tall wheatgrass, Rimrock Indian ricegrass, and Gardner saltbush. In addition all entries were planted in a mixture with Gardner saltbush. Grasses and saltbush were drilled with a plot planter on November, 2011, and forage kochia entries were broadcast on the surface on January, 2012. The evaluation was arranged in a replicated RCB desing and plots were 5 ft X 10 ft in size. Stand evaluations during the spring of 2012 revealed minimal establishment at one exclosure and no establishment at the second exclosure. This is the second year of seeding with minimal success.
In addition, a second spaced-plant study was established in March 2012 by transplanting seedlings of forage kochia, grass, and Gardner saltbush within the second exclosure. All entries and mixtures in the seeded study were included in the spaced-plant study. The plot area was previously prepared by deep tillage and allowed to accumulate soil moisture during the fall of 2011. No additional supplemental water was applied. 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. The purpose of the transplant study is to further elucidate species persistence, compatibility, and competition with halogeton. Most of these transplants died from an apparent late, hard-frost.
The same transplant study had been established at Exclosure #1 in 2011 and during the summer of 2012 data was obtained. Halogeton frequency was determined at 20, 30, 40, and 50 cm intervals in the interspaces between the 1-m spaced rows of plants. Plant vigor will be determined in late summer by harvesting biomass of the transplants.