Improving fertiliser management: Redefining soil test-crop response relationships for canola in Western Australia
Chen, W., Brennan, R., Bell, R.W., Bolland, M. and Anderson, G. (2010) Improving fertiliser management: Redefining soil test-crop response relationships for canola in Western Australia. In: 2010 WA Agribusiness Crop Updates, 25 - 26 February, Perth, Western Australia.
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Canola (Brassica napus) has become a major crop grown in rotation with spring wheat and lupins in Western Australia (WA) since the mid 1990s. Most soils in WA are highly weathered with very low levels of phosphorus (P). The WA soils initially contained adequate indigenous soil potassium (K) for cropping but removal of K over time in the harvested grains has gradually resulted in the some soils becoming deficient in K for grain production. The sulphur (S) status of WA soils was maintained when single superphosphate (containing about 11 per cent S) was widely used as P fertiliser. The increased and widespread use of fertilisers containing lower S levels than single superphosphate, such as DAP and MAP is likely to increase S deficiency in canola. Furthermore, S deficiency has more frequently been identified in canola crops (compared with wheat and lupins). Consequently fertilisers containing P, K and S are now applied to most canola crops.
Fertiliser costs represent a significant part of the variable costs of growing crops in WA. Chen et al. (2009) identified the need for improved soil test interpretation for making fertiliser recommendations due to substantial changes in farming systems, fertiliser practices and crop yield potential since earlier calibrations were developed. The aims of this study were (1) to compile experimental data containing the standard soil test measurements and observed canola crop yield responses for both nil and fertilised treatments across different soil types and seasons from published or unpublished sources, and (2) to critically analyse soil test-crop response relationships to derive better critical soil test values in soils and environments suitable for canola grain production in WA.
|Publication Type:||Conference Paper|
|Murdoch Affiliation:||School of Environmental Science|
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