James Nuttall1, Audrey Delahunty1,2, Ashley Wallace1, Eileen Perry3, Glenn J. Fitzgerald1, Frank Henry4, Kirsten Barlow5
1 Grains Innovation Park, Department of Economic Development Jobs, Transport and Resources, 110 Natimuk Road, Horsham, Vic 3400, Australia Email James.Nuttall@ecodev.vic.gov.au
2 The University of Melbourne, Parkville, Vic, 3000, Australia
3Department of Economic Development Jobs, Transport and Resources, Cnr Midland Highway & Taylors Street, Epsom, Vic, 3551, Australia
4Department of Economic Development Jobs, Transport and Resources, 915 Mount Napier Road, Hamilton, Vic, 3300, Australia
5Department of Economic Development Jobs, Transport and Resources, 124 Chiltern Valley Road, Rutherglen, Vic, 3685, Australia
Frost can significantly reduce grain yield of dryland cropping systems. Understanding the impact of frosts given their timing and severity and early identification are all important factors for effective management and limiting financial loss associated with frost effected areas. An important step in developing frost management tools and technologies is the development of field based methodologies for applying artificial frost treatments to both quantify response and test the utility of sensors at the crop canopy level. This paper reports on the testing of a methodology for imposing frost treatments to field wheat and the subsequent impact on crop yield. Purpose built frost chambers (600 mm W×600 mm D×1200 mm H) clad with Foilboard® and internal platforms containing multiple trays, 300 mm above the crop canopy, allowed for stepped additions of dry ice. Imposed frost treatments were applied over one and two progressive nights and varied in severity from -0.7 to -4.2oC which corresponded to a range in cold sums of 2 to 19oChr (< 0oC). Wheat response was an 8.8% and 7.2% reduction in grain number and yield respectively, for every degree Celsius below zero (up to -4°C) for a single frost event. This respective reduction increased to 15.7 and 11.8% per degree Celsius below zero, (up to -3°C) when frost was imposed over two progressive nights. For cold load equivalent, which combines temperature and duration, there was a 2.2% reduction in grain number per Chr (below 0°C), which translated to a yield reduction of 1.9% per °Chr (below 0°C). Importantly, these results demonstrate that the current frost chamber methodology effectively created a backdrop of wheat, differentially effected by frost.