Identifying soil constraints that limit wheat yield in the south-west of Western Australia
Wheat is grown on about 18 million hectares in the South-West Agricultural Region of Western Australia from north and east of Geraldton to Esperance in the south-east. Yields are frequently constrained by a range of soil factors.
This report uses existing conventional soil-landscape mapping to analyse the effects of 17 known soil constraints that limit crop production and roughly prioritises the areas where they occur.
Traditional land capability maps are prepared using a most-limiting factor approach, which assumes that ameliorating the most limiting constraint will result in a yield increase until the next most-limiting constraint is reached. Where there are few (1–3) overlapping soil constraints, regional-scale mapping — as used for this report — identifies land where spending time and money to ameliorate these constraints may be cost-effective in increasing economic returns because there is some yield benefit before the next constraint is reached. When many (>3) overlapping constraints occur, the returns from fixing one constraint may not be economic, due to the yield-limiting effects of the other constraints.
Information provided in this report is suitable for regional-, local- and catchment-scale planning. It uses unmapped proportionally allocated land units within map units. Where a land manager can identify these unmapped land units, it should be a reasonable starting point for farm-scale planning. At the very least, it prioritises likely constraints to be explored.
Number of Pages
soil constraints, soil-landscape mapping, map units, crop production, south-west of Western Australia
van Gool, D 2016, ‘Identifying soil constraints that limit wheat yield in South-West Western Australia’, Resource management technical report 399, Department of Agriculture and Food, Western Australia, Perth.
Maps are not included as part of the complete document download. If this report contains a map, it will be available in the individual parts list below.