Variation in Growth Rates under Saline Conditions of Pascopyrum smithii (Western Wheatgrass) and Distichlis spicata (Inland Saltgrass) from Different Source Populations in Kansas and Nebraska: Implications for the Restoration of Salt‐Affected Plant Communities

Abstract

Soil salinization resulting from agricultural and oil-and gas-production activities can impact habitats of native flora and fauna and reduce production on agricultural lands. Restoration of saline areas with salt-tolerant vegetation may alleviate impacts. However, differences in how the growth rate under saline conditions varies between species and source populations must first be evaluated before recommending species for restoration. Plant material of Western wheatgrass (Pascopyrum smithii) and Inland saltgrass (Distichlis spicata) collected from Cheyenne Bottoms Preserve, Kansas and Little Salt Fork Marsh, Nebraska was propagated to evaluate variation in growth rates between these species under saline conditions and determine if differences exist between populations within these species. Ten transplants of each species from each location were grown in sand culture in a greenhouse for 51 days and watered with one of five different saltwater solutions (0.86 dS/m, 9.85 dS/m, 17.85 dS/m, 32.5 dS/m, and 57.7 dS/m). Results indicate that P. smithii grew faster than D. spicata at all comparable salinity levels. Only D. spicata exhibited significant differences in growth rate under saline conditions between populations. Results suggest that P. smithii is equivalent to D. spicata in salt tolerance and should be regarded as an appropriate halophyte for restoration of salt-affected plant environments. Results for D. spicata suggest that differences between source populations should be considered when evaluating plant material for plant community restoration.

Initial Plant Growth in Sand Mine Spoil Amended with Organic Materials

“…Electrical conductivity was 27.83 dS/m in the sludge treatment. While successful growth of native grass transplants has been shown at salinity levels above 57 dS/m (Aschenbach 2006), the electrical conductivity in the sludge treatment is well above the 15-20 dS/m threshold that constrains germination in non-halophytic plants (Larcher 1995). Soil pH of ≥ 5.5 is recommended for optimal growth of warm-season grasses (Dickerson et al 1998); spoil amended with sludge exhibited a mean pH of 4.9.…”

Historical range of variation assessment for wetland and riparian ecosystems, U.S. Forest Service Rocky Mountain Region

“…Salt flats most commonly occur in arid and semi-arid landscapes where evapotranspiration exceeds precipitation throughout the year (Aschenbach 2006). However, saline wetlands are also abundant in more humid regions such as the prairie pothole region of the northern Great Plains (Last and Ginn 2005;Lieffers 1984).…”

“…Estimates of salt affected soils have been developed within individual states and maps showing the distribution of saline soils may be found on some county soil surveys. More than 400,000 ha of soils are classified as salt affected in Kansas (Aschenbach 2006). Salt flats are generally restricted to the Great Plains, although saline ecosystems also occur at high elevations in intermountain basins.…”

“…Oil and gas extraction-Soil salinization can occur associated with oil and gas production since salt water, consisting primarily of sodium chloride (NaCl) is often encountered during drilling operations. While water may be reinjected into disposal wells or deposited in on-site reserve pits, contamination can occur from accidental spills or lateral subsurface movement of reserve pit brine (Aschenbach 2006). Contamination from brine spills can result in the death of vegetation and reduced forage production on rangelands or crop yields on agricultural lands.…”

“…Any control structures (e.g., drainage tiles or ditches) need to be identified and removed. Proper selection of species is important, particularly for salt flats, since the salt tolerance of different species varies widely (Table 27) and ecotypic variation should also be considered (Aschenbach 2006). Seeds for restoration can be collected in the field, stratified, germinated, and grown into seedlings for use in restoration projects.…”