Previous PageTable Of ContentsNext Page

Effects of crop and pasture rotations on the water use and yield of wheat

M. Walsh

Mallee Research Station, Department of Agriculture, Walpeup VIC 3507

The sandhill soils of the Victorian Mallee naturally have low levels of nutrients and poor water storage capacity which leads to poor crop and pasture growth, a lack of vegetative cover and high susceptibility to wind erosion. A long-term rotation experiment aimed at improving the productivity of sandhill soils was established in 1988 at the Mallee Research Station, Walpeup. Four rotations (Table 1) were evaluated for their effects on soil water conservation, cereal cyst nematode, dry matter production and grain yield.


Soil moisture measurements were recorded at sowing, anthesis and harvest using a neutron moisture probe calibrated at 0.2 m intervals down the soil profile to 2 m. Dry matter production and the number of cereal cyst nematode (CCN) cysts per plant were recorded at anthesis. Grain yield was measured at harvest.

Results and discussion

The fallow in a pasture/fallow/wheat rotation did not significantly (p>0.05) increase the amount of water stored in the profile at sowing compared with a wheat/lupin/wheat and a lupin/lupin/ wheat rotation (Table 1) and hence there was no difference (p>0.05) in the total water use at anthesis or harvest. A lucerne pasture decreased (p<0.05) the total soil water at sowing resulting in the wheat using less water at anthesis and harvest.

Table 1. Effect of rotation on cereal cyst nematode (CCN) and dry matter production (DM) at anthesis, grain yield at harvest, total soil water (TSW 0-2 m) and total water use (TWU 0-2 m) for wheat crops in four rotations

The lupin/lupin/wheat rotation had significantly lower CCN cyst numbers than the other rotations (P<0.05). This rotation also had a substantially higher anthesis dry matter production and grain yield. This effect is likely to be a consequence of lower CCN numbers and the additional nitrogen input from the two previous lupin crops. The wheat in the lucerne/lucerne/ wheat rotation suffered greater water stress and would not have benefited from additional nitrogen.

Previous PageTop Of PageNext Page