ON FARM NATIONAL FEEDBASE f Feedbase future‑proofing “I t’s like putting pasture plants and resilience in climate extremes. This has for summer growth, and what plant in a time machine and taking will help us identify traits that enable and microbial traits are associated with them to climate conditions plants to cope with the more extreme faster and/or more complete sward predicted for the future,” conditions that are predicted to occur, recovery, both in terms of productivity Professor Sally Power says of the more often and for longer,” Sally said. and nutrition.” Pastures and Climate Extremes “Those characteristics will in turn help us Glasshouse trials (PACE) project she leads. identify other species and cultivars with Along with the polytunnel trial plots, those traits, so ultimately producers can glasshouse experiments are being “We’re looking at what the climate is choose ones more likely to perform well used to assess specific aspects of likely to be later this century, which in future, more extreme climates.” climate resilience. in southern and eastern Australia is generally warmer, with higher CO2 Early indications “Importantly, glasshouse experiments concentrations, more heat waves and “Our two main climate treatments – will also allow us to evaluate the reduced spring and winter rainfall, and warming (+3°C) and [winter/spring] impact of elevated COconcentrations2 seeing how that affects pasture growth.” drought – were initiated in 2018 and (a key component of future climate we’re now seeing some interesting predictions) on species’ performance, Keeping up the pace treatment effects,” Sally said. and interactions between plants and Based at the University of Western their symbiotic microbes,” Sally said. Sydney’s Hawkesbury Campus, the Early observations included: PACE project is funded by MLA Donor • fescue productivity in late spring “Our preliminary findings confirm that Company and Dairy Australia. It started was particularly reduced in drought grasses grown with legumes are much at the end of 2016 with the construction conditions, with an 80% decrease more productive than grasses grown of six large polytunnels to enable compared to control plots recorded in on their own and, in particular, that they climate control. Infrared heat lamps are November 2018 benefit from elevated CO when grown2 used to increase air temperature and in combination with legumes, but not • biserrula was the most strongly when grown alone.” rainfall is added in line with current and affected legume in spring 2018, with future rainfall scenarios. a 50% reduction in productivity in The researchers believe this grass The first phase of the project will run for drought plots compared to a decrease biomass increase was caused by the three years. of 33% for lucerne grasses accessing additional nitrogen • tropical C4 grasses maintained higher fixed by the legume, which grew more Hot and dry yields in drought conditions than their in the presence of elevated CO, even2 Not all experimental plots are being temperate counterparts, although though the grasses themselves did exposed to heat stress, but all are being yield reductions of up to 50% were not appear to benefit directly from ‘droughted’, with watering applied at still observed at the end of spring. increased CO.2 a rate that reflects a 60% reduction in This increase in legume ‘facilitation’ winter and spring rainfall. This is roughly Recovery after drought is an important equivalent to the climate experienced aspect of a species’ resilience, so of grass growth is an interesting in many parts of NSW in 2018, so the will be carefully monitored by the mechanism that may contribute scenario is entirely realistic and will researchers. to enhanced performance of provide useful, real‑world information. mixed pastures in future increased “Big species differences in mortality at concentrations of atmospheric CO. ■2 Research plots have been planted the end of the drought (e.g. 80% dead with a range of widely grown pasture fescue, compared to 0% dead kangaroo Professor Sally Power grasses and legumes to enable testing grass) will undoubtedly influence University of Western Sydney of their response to drought and recovery trajectories, and this is one E: s.power@westernsydney.edu.au heat stress. of the things we are looking at during “B measuring a suite of physiological,y autumn,” Sally said. Above: Each polytunnel used for the PACE morphological and biochemical traits, “We need to know how our treatments project houses sub‑plots planted with fescue – either individual species or mixtures – to enable we hope to provide new insight into the affect pasture persistence, how much researchers to assess pasture performance mechanisms that determine sensitivity of a legacy winter and spring drought under a predicted future climate scenario. 26