Productivity of crops grown on raised beds on duplex soils prone to waterlogging in Western Australia

Waterlogging of duplex soils in Western Australia has long been recognised as a major constraint to the production of agricultural crops and pastures. The work described in this paper examines the application of raised beds to arable land that is frequently waterlogged for the production of crops such as wheat, barley, field peas, lupins and canola. Raised beds are 138 cm wide, seed beds separated by 45 cm wide furrows 183 cm apart. These beds were made with a commercial bed former. Seven sites were selected across the south-eastern wheat belt of Western Australia with the experimental areas varying in size from 10 to 57 ha. These large sites were used to accommodate commercial farm machinery. Each site had raised beds formed with a commercial bedformer. The production from the bedded areas was compared with crops grown conventionally on flat ground under minimum tillage as the control. The experiments were established in 1997 and 1998 and the sites were monitored for a maximum of 5 years. In 11 of the 28 site-years of the experiments, grain yields on the raised beds were statistically significantly higher than the yield from crops grown on the control, with an average yield increase of 0.48 t/ha. Across the whole dataset, growing crops on raised beds did not produce significantly lower yields. Below average rainfall was received for much of the experimental period at several sites. Growing season rainfall had a large effect on grain yield and high rainfall over a period of 40 days after seeding significantly increased the grain yield difference between the raised bed and the control. These data indicate that the use of raised beds lead to higher grain yields when seasonal conditions are appropriate.