Eusun Han1, Mr Tony Swan3, Dr Jeremy Whish3, Dr Julianne Lilley3, Dr Xiaoxi Li3, Gabe Brown3, Matt Hicks3, Kristian Thorup-Kristensen2, Dr John Kirkegaard3
1Aarhus University, Department of Agroecology, Tjele, Denmark, 2University of Copenhagen, Department of Plant and Environmental Sciences, Høje Taastrup, Denmark, 3CSIRO, Agriculture and Food, Canberra, Australia
Biography:
I am a digital agronomist with a proven track record for high competency in research and communication. My key research areas cover root biology, digital phenomics, resilient farming systems and sustainable intensification. I have developed novel methods (digital and biochemical) to reveal several fundamental plant-soil mechanisms in relation to solving complex problems in agriculture such as climate change.
Abstract:
The implications of grazing dual-purpose wheat crops on the water relations of the crop are important for grain yield recovery in dryland environments. Removal of the transpiring canopy in winter may reduce water uptake and defer its use into spring during the critical period, while impacts on root depth and density may restrict water capture. In a series of three field experiments in southern NSW (2021-23) root depth (m) was also temporarily reduced by around 20 cm following shoot removal when measured within 200ºC days (21 days) after grazing in 2022 and 2023. During two very wet years (2021-2022), there was a temporary reduction in water use in shallow soil layers until stem elongation (Z39), but wet conditions thereafter maintained the soil close to the drained upper limit (DUL). In the drier season in 2023, reduced water use post-grazing was associated with changes in real-time canopy temperature measurement during stem elongation, but no distinctive effect of deferred water use on grain yield was observed during the three years. Further modeling efforts will identify the seasonal conditions and circumstances in which the temporary cessation of root growth following grazing influences crop yield.