Mortality of crested wheatgrass and Russian wildrye during drought.

Abstract

From September 1987 through September 1988, the Northern Great Plains near Miles City, Mont., received 31% of the long-term average precipitation. We monitored the impact of the hot, dry conditions during the growing season on mortality of tillers and plants of 'Vinall' Russian wildrye (Psathrostachys juncea [Fisch.] Nevski) and 'Nordan' crested wheatgrass (Agropyron desertorum [Fisch.] Schult). Plants were collected in the field, watered, and placed in controlled environments. Ninety-two percent of the wildrye plants collected in July produced green shoots. Fifty-seven percent of the wheatgrass plants collected in July produced shoots. The maximum percentage of wildrye and wheatgrass plants producing green shoots in August was significantly (p less than or equal to 0.10) less than in July. Transects were used to sample density of dormant and live plants after September rains, and plants were incubated as before. When transect and incubation data were combined, only 41% of the wildrye and 16% of the wheatgrass plants were deemed viable in September.