Environmental response of spring wheat in the south-western Australian cereal belt
1987
Rickert, K.G. (Queensland Agricultural College, Lawes (Australia)) | Sedgley, R.H. | Stern, W.R. (Western Australia Univ., Nedlands. School of Agriculture)
The performance of the spring wheat cultivar Gamenya was studied under typically dry conditions on two contrasting soil types: a heavy clay loam and a light loamy sand overlying clay. The total water use was similar on both soils and was of the order of 240 mm. On the heavy-textured soil at high nitrogen, the foliage canopy developed more rapidly than on the light soil, resulting in earlier soil water depletion and haying off. Water use efficiencies were similar to those reported for winter rainfall areas in south-eastern Australia. This suggests a greater degree of buffering against spring drought than is indicated by the high ratio of pre-anthesis to post-anthesis water use. Data on the partitioning of dry matter indicated that this buffering of the harsh spring conditions at Merredin may be due to a greater contribution of assimilates from pre-anthesis storage to grain filling. In dry environments, further critical evaluation is needed of the role of stored assimilates in grain formation. Faster canopy closure on the heavy soil resulted from a higher density of shoots and possibly larger leaves. This led to the suggestion that on heavier, more fertile soils, an ideotype with restricted tillering may be higher yielding. By the end of the season ear bearing shoot densities and total water use were the same on both soil types, thus masking earlier important differences.
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