Vegetable crop nutrition on sandy soils of the Swan Coastal Plain

Page last updated: Friday, 24 October 2014 - 8:46am

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Spreading method

The best method to apply fertiliser will vary with the type of crop and its growth stage.


Broadcasting is best suited for pre-planting applications such as superphosphate and compost. It can also be used on direct-sown or transplanted crops when they are very small and fertiliser granules will not lodge in leaf axils, causing crop damage. Only granular or bulky organic fertilisers are suitable for this method and it can be inefficient because placement is erratic and widespread.


Banding is well suited to row crops in the weeks leading up to row closure. It can allow high rates of fertiliser to be accurately placed for a crop with a rapidly growing fertiliser demand. It is only suitable when the crop has a large enough root system to use fertiliser placed between rows.

Boom spraying

Boom spraying can be used to apply foliar — leaf absorbed — nutrients or as an alternative broadcasting method for higher rates on young crops. It is far more accurate than a fertiliser spinner, except in windy conditions. There are limits on rates that can be applied without foliage damage if overhead irrigation is not employed at the same time as spraying.


Fertigation can be used throughout the crop life but tends to be used more after row closure. It is a cheap, effective method of distributing nutrients which allows regular application. Its main downfall is that it can be erratic in windy conditions and often leads to overdosing on multiple crop maturities.

It is probably at its best when used to apply a low ‘base load’ rate throughout the crop’s life. This ‘base load’ should be sufficient to establish the crop but would need topping up by other methods later in the life of the crop when these methods are practical. To achieve this, automated sprinkler systems need to be developed.

Choosing products

Cost and performance are important when choosing a product, but it is not always that simple.

The products you choose should supply large quantities of the major nutrients nitrogen, phosphorus and potassium (NPK), moderate quantities of calcium and magnesium and small quantities of trace elements. Products which supply all of these in one bag are usually more expensive because of the cost of mixing or blending.

Some nutrients may also be applied that are already in plentiful supply in the soil.

Single-nutrient products with high concentration are usually cheaper because there are no mixing costs and freight costs per unit of nutrient are lower. However, you may need to mix these yourself to fit into your management system and this is additional cost. Alternatively, you may need to make an extra pass over the crop to apply two fertilisers in single nutrient form. Not all products are stable when mixed and must be applied separately.

Choose a product that best matches the distribution method you plan to use. This may vary at different stages of the crop’s life. If you want to fertigate for example, some products do not fully dissolve in water and are unsuitable for this system.

Decide first how to apply fertiliser for a particular crop stage then choose the cheapest, most user-friendly product which contains the nutrients the crop needs and suits that method.

Contact information

Rachel Lancaster
+61 (0)8 9780 6210