Fertiliser requirements should be based on soil testing. High yielding brassica crops have a large nutrient requirement. The nitrogen (N) requirements can range from 250 to 500kg N/ha. While total crop requirement for phosphorous (P) is quite low, it is vital during establishment and for shallow rooting brassicas. The application of P in a base dressing and down the spout at planting will provide good response particularly on low P soils. Growing brassicas on effluent ground may allow significant reduction in fertiliser inputs but again this should be on the basis of soil testing and knowledge of crop requirements.
The soil pH level should be at least 5.6 and ideally between 5.8 and 6.2 for most brassicas. Crops should have at least 40-60 kg phosphate/ha available at sowing.
Paddocks should have low soil sulphate levels. After grazing, a light application of nitrogen will greatly increase yields of subsequent growth. Use of nitrogen may increase problems of high crop nitrate content; test levels before grazing.