Dr Martin Harries1, Mr Wayne Parker1, Prof. Ken Flower2
1Department of Primary Industries and Regional Development (DPIRD), 2UWA School of Agriculture and Environment and UWA Institute of Agriculture
Biography:
Martin has been involved agronomic research into broadleaf species and their integration into farming systems for the past 22 years. Currently he is Research Lead of the Western Farming Systems Project ($20m), overseeing field trials. Previously he has led other projects such as “Putting the Focus on Profitable Break Crop and Pasture Sequences in WA” ($14m) and “Expanding the sowing window for canola and lupins – what works in WA” ($2m).
Abstract:
In recent years substantial changes to Western Australian broadacre farming systems include large reductions in area of pasture and grain legumes, increased canola production and more frequent cereal plantings. We investigated the impact of this on production constraints; weeds, plant pathogens and soil nutrition and implications for water use efficiency of wheat crops.
A survey of 184 fields over 6 years totaling 3730 field visits was used to monitor a wide range of biophysical variables and obtain accompanying field management data from fields across south-west WA.
Weeds, diseases and nutrients were well managed in the vast majority of fields. WUE for wheat production averaged 10.7 kg.mm/ha. After a break crop or pasture this increased to 12.5 kg.mm/ha while reducing to 8.4 kg.mm/ha in the fourth successive wheat crop. A French and Schultz style boundary function indicted low evaporation (45 mm) and high mean transpiration efficiency (25 kg/mm) for fields with the highest WUE. We found that some of the traditional functions provided by break crops and pastures, were in-part, replaced by external inputs and management, with weeds, diseases and nutrients well managed in most fields. However, including break crops and pastures to minimise long sequences of monoculture wheat remains critical to ensuring high WUE in this dryland farming system. Results are published as a series of four papers, with a PhD thesis recently completed.