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Rooting depth of a range of crop species on sandhill soils in the Victorian Mallee

M. Walsh

Mallee Research Station, Walpeup, Victoria, 3507.

Victorian Mallee sandhill soils generally consist of light sand over a clay subsoil (1). As the sand is inherently infertile with a low waterholding capacity it appears probable that plants are dependant to some extent on the clay subsoil for water and nutrients. The aim of this study was to determine the rooting depth of a range of crop species on a sandhill soil.


Six crops (lupins, mustard, rye, triticale, barley and wheat) were sown on a sandhill which had a clay subsoil at a depth of approximately one metre. Each crop was replicated three times in a randomised block design. At anthesis, four soil cores (42 mm diameter x 2000 mm length) were taken from a weed free area, divided into 200 mm segments which were composited into two samples for each depth. Roots were extracted from each sample by washing through a 1 mm screen.

Results and discussion

Each crop had extended roots at least one metre into the clay subsoil as roots were found at two metres depth for all crops (Table 1). Although the percentage of roots in the clay subsoil was low for all crops it is possible that these roots could have played a major role in supplying plants with water and nutrients.

Table 1. Root dry matter production (g m-') for a range of crop species grow on a sandhill soil (standard errors in parentheses).

However above ground dry matter production and grain yield were low for all crops, so that despite roots having penetrated the subsoil, albeit to a limited extent, this was of little or no benefit as growth was severly restricted by a lack of water and nutrients.

1. Badawy, N.S. 1982 Dept Agric Vic, Technical Report Series. No.55.

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