The use of herbicides and rotations to control weeds, in association with minimum tillage, has enabled earlier planting and improved use of seasonal rainfall. The increased PUE has arisen from a number of agronomic and genetic advances. This has enabled producers to maintain economic viability. Over the past 25 years, yields have doubled while rainfall has declined, resulting in a greater than doubling of the rainfall use efficiency or Precipitation Use Efficiency (PUE). Wheat is the principal crop in the Western Australian rainfed farming system. Additionally, opportunity was taken to compare and contrast experiences both within Western Australia and throughout Australia, and to draw out management options for crop production on duplex soils. This special issue was initiated to summarise that research and to put it in its regional and national perspective. This research has been focussed on 3 sites at which processes limiting crop production on duplex soils have been highlighted. Research on crop production on duplex soils has been undertaken for the past 8 years by a collaborative team from the CSIRO Dryland Crops andyoils Program and the Western Australian Department of Agriculture. Crop production is restricted to the winter and spring and is limited by waterlogging in the wet winter months and by water shortage during grain filling in spring. The climate is characterised by cool, wet winters and hot, dry summers.

Annual crops of wheat, barley, oats, and lupins predominate on these soils, grown in rotation with annual pastures. Duplex or texture-contrast soils occur over about 60% of the agricultural areas of south-west Western Australia.

Cracked by R.K. Belford