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As stated in the referenced article, a species which is considered <br />moderately sensitive may expect some decrease in yield when the soil <br />salinity, measured as ECe, is in excess of 1.5 mmhos/cm. A moderately <br />tolerant species may show evidence of decreased yields at an ECe of 3.0 <br />mmhos/cm. Few of the grasses, forbs, and woody plants growing adjacent to <br />the creeks and in the irrigated pastures have been thoroughly studied; thus, <br />limited information is available. The article of Maas and Hoffman does <br />report salt tolerance levels for some of the genera. Orchard grass <br />(Da~~ct~y~l~is log merata) and timothy (Phleum pratense) are considered <br />moderat~y sensitive. Although the specec es A~rost~is al~ustr~is, which is <br />considered moderately sensitive, was not found in~area, other genera of <br />Agrostis located in this region were assumed to be moderately sensitive. <br />Smooth brome (Bromus inermis), mountain brome (Bromus carinatus), <br />reed canarygrass rPha ar'~is arundinaceae), tall fescue Festuca <br />elatior which equals F. pratensis wheat (Tr iticum aestivum , <br />crested wheatgrass (A ro ron desertorum), and slender w e~i atgrass <br />(Agropyron trachycaulum are classified as moderately tolerant. Other <br />species of moderately tolerant grasses include barley (Hordeum vulgare) <br />and tall wheatgrass (Agropyron elongatum). It is assumed other genera <br />of Hordeum, Agropyron, and Festuca such as foxtail barley (Hordeum <br />broth antherum), intermediate -Tatgrass (Agropyron trach~au um , <br />western w eatgrass (Agropyron smithii), wheatgrass (A ro~,r~on), and <br />Idaho fescue (Festuca idahoensis) are moderately tolerant asas9~ Of the <br />forbs alfalfa Medico- o~ a) and clover (Trifolium) are considered <br />to be moderately sensitive. For the purpose of this discussion, if a <br />particular species had been classified in terms of salt tolerance, such as <br />Agrostis palustris or A rg opyron elongatum, then other similar genera <br />were rated within the respective category. An example would be rating <br />A rostis (species) as moderately sensitive or A~r~op ron intermedium as <br />mo erately tolerant. None of the grasslike plants or sFir~iu s encountered in <br />the area studied were rated for salt tolerance in the article of Maas and <br />Hoffman. <br />However, as recently discussed in "Salinity Tolerance in Plants, <br />Strategies for Crop Improvement" (edited by Richard C. Staples and Gary H. <br />Toenniessen, 1984), some genera of the families Cyperaceae and Juncaceae <br />exhibit salt tolerance. These grasslike plant families include the genera <br />Carex and Juncus. The particular species which were studied are not <br />owed in t7iis region, however, other species which grow in the area are <br />likely to be salt tolerant as well. Twentymile Coal Company has thus <br />regarded species of Carex and Juncus as moderately tolerant. <br />Table 1, Middle Creek Alluvial Valley Floor Vegetative Cover, describes <br />the vegetative cover and composition for Pastures 1 and 2 on a weighted <br />average basis. A total of 30 cover transects were conducted. The total <br />vegetative cover is 74.3%. Grasses comprise 61.6%, grasslike plants cover <br />3.0%, and forbs cover 9.7°b. Of the grasses, slender wheatgrass, smooth <br />brome, and tall fescue are considered moderately tolerant. Similar species <br />of other tolerant grasses include intermediate wheatgrass, western <br />wheatgrass, and Idaho fescue. The total cover of moderately tolerant grasses <br />is 38.6°~. The moderately tolerant sedges and rushes cover 3.0°~. Using the <br />weighted averages as presented on Table 1, the moderately tolerant species <br />cover 41.6% of the irrigated area, or 56.0% of the relative composition. <br />Moderately sensitive grass species (orchard grass and timothy) are found in <br />