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<br /> <br />4 <br /> <br />Elemental Concentrations <br />Tall fescue accumulated the greatest amount ofCI" and Na+. Broad-Ieafbirdsfoot accumulated <br />the greatest amount of Ca2+ and Mg2+ among the three species. Generally tissue Ca2+ <br />concentrations were higher in treatments I thru 3 (good soil) than treatments 4 thru 6 (poor soil) <br />for all species, while Na+ and CI' concentrations increased in shoot tissue in treatments 4 thru 6 <br />(Table 5 and 6). Generally, soil EC levels and all tested elements increased with addition of poor <br />quality water. Interesting to note; soil EC did not increase to the same magnitude in postharvest <br />soils from tall fescue as compared to both varieties of birds foot trefoil (see Table 1). <br /> <br />Discussion <br /> <br />Based upon the conditions described and presented by Colorado State University Extension, tall <br />fescue appeared to tolerate the poor soil and poor quality water conditions better than narrow and <br />broad-Ieafbirdsfoot trefoil. <br /> <br />Plant tolerance to salinity is usually appraised in one of three ways: 1) the ability ofa plant to <br />survive on saline soils, 2) the absolute plant growth or yield, and 3) the relative growth or yield on <br />saline soil or with saline water compared with that on nonsaline conditions. In this study, the <br />third point of criteria was primarily used for determining salt tolerance. Salinity can affect plants <br />at all stages of development, but sensitivity sometimes varies from one groWth stage to the next. <br />Tall fescue did not appear to show significant decreases in dry matter production among the <br />different treatments at any clipping, although DM gradually increased to a point in its growth <br />cycle and then gradually decreased. For both narrow~ and broad-leafbirdsfoot; significant DM <br />differences among the treatments were easier to detect. Interestingly, treatments containing either <br />poor soil or poor quality water slightly stimulated DM production in both varieties of birds foot, . <br />especially in narrow-leaf. The influence of clipping frequency or interval regime on biomass <br />production was not evaluated in this study, but likely influences growth of tall fescue and <br />birdsfoot trefoil. <br /> <br />Current evidence indicates that, in general, plant growth of any plant is most closely related to <br />water uptake. We found this relationship to be true in our study. During our designated growing <br />season, tall fescue received up to 27 liters of water per pot, while both varieties of birdsfoot <br />trefoil received approximately 20 liters, irrespective of treatments. Consequently, total dry matter <br />yields were considerably greater for tall fescue. Care was taken with irrigation to avoid contact <br />with plant and water applications. This precaution allowed for a more accurate evaluation to be <br />made on the species ability to accumulate ions through their roots, since plants can absorb ions <br />directly through their leaves. <br /> <br />Changes and differences in shoot ion concentrations with salinity treatments could be observed in <br />the three species. Generally leaves are susceptible to injury by the toxic accumulation ofCl', or <br />Na+, or both in the leaves, Injury may depend more on leaf characteristics and the leaves' rate of <br />absorption than on a plant's tolerance to soil salinity. Rates of salt absorptions may increase when <br /> <br />