Fertiliser
On sandy soils, apply 50 cubic metres of compost per hectare in the rotation or before planting. This supplies organic matter, adds nutrients and helps retain moisture in the soil.
Apply the following rates of magnesium and trace elements before planting:
- 50kg/ha magnesium sulphate to supply magnesium
- 20kg/ha manganese sulphate to supply manganese
- 18kg/ha borax to supply boron
- 18kg/ha iron sulphate to supply iron
- 18kg/ha copper sulphate to supply copper
- 18kg/ha zinc sulphate to supply zinc
- 2kg/ha sodium molybdate to supply molybdenum.
Starting two weeks after emergence, topdress with a compound NPK fertiliser of around 12% nitrogen, 5% phosphorus and 14% potassium plus trace elements at rates of 200–300kg/ha every 14 days on infertile sandy soils, commencing with the lower rate.
The suggested fertiliser program is for a soil of low fertility. Test soil for phosphorus and irrigation water for nitrogen, phosphorus and potassium before planting.
Some phosphorus will be retained in sandy soils with a yellow or brown surface colour but not in grey or white sands. Some nutrients may be omitted or reduced if they are sufficiently high in the irrigation water and soil, or from compost and fertilisers from previous cropping.