Published online by Cambridge University Press: 20 January 2017
Greenhouse studies were conducted to determine the relative salinitytolerance of foxtail barley and seven desirable pasture grasses. Grassspecies were reed canarygrass, timothy, altai wildrye, tall fescue, tallwheatgrass, orchardgrass, creeping meadow foxtail, and foxtail barley.Grasses were exposed to increasing electrical conductivity levels of NaCland CaCl2 salt solution over time. Grass species were comparedusing a cumulative value of salt exposure (ECdays), which wascalculated to account for the electrical conductivity (EC) and the time aplant was exposed at that level of conductivity. Salinity tolerance variedamong grass species. Increasing EC significantly reduced plant biomass ofall species. All grass species experienced a 50% biomass reduction (GR50) between 271 and 512 ECdays in 2008 andbetween 297 and 575 ECdays in 2009. Foxtail barley was among themost salt tolerant (GR50 = 512 and 525 ECdays),requiring the highest salt exposure in 2008 and the second-highest exposurein 2009 to reduce biomass 50%. Grass mortality increased with increasing EClevels. Reed canarygrass and timothy were most susceptible to increasingsalinity, with 50% mortality (LD50) of both grass speciesoccurring between 983 and 1,186 ECdays. Moderate salinitytolerance was exhibited by orchardgrass, which required 1,977 and 1,844 ECdays; creeping foxtail, which required 1,998 and 2,431 ECdays; and tall fescue, which required 2,501 and > 2,840 ECdays to LD50 in 2008 and 2009, respectively.Foxtail barley, altai wildrye, and tall wheatgrass were most tolerant ofsalinity and persisted with little mortality occurring at 3,033 and 2,840 ECdays in 2008 and 2009, respectively. All grass species withhigher growth rates than foxtail barley and altai wildrye were moresusceptible to salinity, with the exception of tall wheatgrass. Growth ratesof foxtail barley and altai wildrye were less than they were for othergrasses, suggesting that slower growth rates may aid in salinitytolerance.