Journal of the Department of Agriculture, Western Australia, Series 4


Duplex soils - soils with a sandy topsoil overlying a clayey subsoil -are ividespread in Western Australia's agricultural areas (see map). These soils are potentially highly productive, but crop growth is variable and the soils can become waterlogged. Work on a duplex soil site near Beverley has shoivn that the soil ivaterlogs where the permeability of the clay is low, and that this permeability varies ividely over the site. Waterlogging accounts for an average of half of the variation in wheat yields on this site; surprisingly, lupins have so far appeared less sensitive to waterlogging- The Department of Agriculture and CSIRO dryland crops and soils group are studying the causes of reduced crop growth on duplex soils to devise management strategies to overcome the problems.