Mary-Jane Rogers, Alister Lawson and Kevin Kelly
Department of Economic Development, Jobs, Transport and Resources (DEDJTR), 255 Ferguson Rd. Tatura, Victoria 3616, email@example.com
Field research is being conducted in northern Victoria, Australia to evaluate how perennial ryegrass genotypes vary in their ability to survive summer drought, and to determine irrigation and grazing management strategies that may enhance perennial ryegrass persistence and production. One experimental site involves 15 perennial ryegrass and tall fescue cultivars and two summer irrigation strategies (full and nil irrigation). Two other experimental sites involve 7 ryegrass cultivars, two summer irrigation strategies (limited and nil irrigation), two summer grazing strategies and an oversowing component. To date, there have been no clear effects of ryegrass genotype and/or genetic background on summer survival at any field site nor any consistent effects of either summer grazing or oversowing in any of the irrigation bays. Ryegrass plant frequency (density) in the following autumn hasn’t differed between perennial ryegrass genotypes but has been higher in the irrigation bay that was fully irrigated (grass presence measured at 97% at the Tatura site) compared with the bay where summer irrigation has been restricted (grass presence measured at 72% at the Tatura site). Autumn and winter pasture accumulation has varied across years, sites and irrigation bays, and appears to be related to the amount of residual pasture mass that is present prior to restricting irrigation. Further research is being undertaken to investigate whether the residual pasture mass and water soluble carbohydrate reserves at the start of the dry period impacts either summer survival or subsequent pasture accumulation.