Mortality in Crested Wheatgrass and Russian Wildrye

Abstract

Mortality in crested wheatgrass and Russian wildrye near Kamloops, B.C., was observed in spring, 1970, and appeared to result from lower than average soil moisture reserves the previous season. Damage was heavy on a silt loam that graded to loamy fine sand at 50-cm depth but was negligible on a uniform sandy loam overlying cobbly loamy sand. Field moisture levels below 25-cm depth in the soil were greater on the sandy loam site than on the silt loam in spring, 1970. In that year, crested wheatgrass reached seed-set stage on the former, but inflorescences did not emerge from the boot on the latter site, where significant mortality occurred. No other published account of severe mortality of established stands of these grasses has been found.