Farm-scale zoning of extreme temperatures in Southern Mallee, Victoria, Australia

Extreme temperatures around the flowering of wheat have the potential to reduce grain yield and at farm scale their impact can be spatially variable. In this study, the zoning of extreme temperatures, using data collected over two years, was carried out for a 164 ha farm in the Southern Mallee, Victoria, Australia in order to identify areas at high risk of extreme temperatures around the time of the flowering of wheat. Twenty-five data loggers were installed at 0.8 m height across the farm to spatially record the daily course of temperatures around the average date of flowering for the region. After applying the zoning algorithms, the maps of different temperature zones were produced by spatial interpolation in ArcView 3.2. It was found that in 2003, about 58% of the farm area was prone to exposure to higher temperatures and about 73% to the lower temperatures whereas in 2004 about 46% of the farm area was prone to exposure to higher temperatures and about 39% to the lower temperatures.