Articles
THE MINERAL NUTRITION OF WINE GRAPES IN AUSTRALIA
Almost all are low in plant available phosphorus and often are alkaline and low in organic matter.
Most supply potassium well.
Australian viticultural regions are predominantly in winter rainfall areas, and grape quality is controlled by management of the irrigation of the vines rather than nutrient availability.
Drip irrigation is widely used.
Phosphorus is applied prior to vineyard establishment, and nitrogen is applied by fertigation.
Micro-nutrients (zinc, manganese) are applied as foliar sprays, frequently during vineyard establishment and once or twice each year prior to flowering in mature vineyards.
In some districts, winter cover cropping with cereals or leguminous crops is common, in others a permanent sod is established.
Chicken litter or NPK fertiliser are used to stimulate bulky growth.
There is interest in mulching with green waste.
Soil analysis is used to define any need for basal applications of fertiliser before vineyard establishment, and later for monitoring and problem solving.
Sampling the root zone of a vineyard is difficult.
Nutritional monitoring is often done by analysis of petioles collected at flowering time.
There is interest in other sampling procedures aimed at getting information earlier in the season.
Petiole analysis does not give a good picture of nitrogen status except in very high yielding vineyards, probably because other factors are limiting performance.
Grape growers are being targeted with a large number of new fertiliser products including liquid and solid formulations for fertigation, multi-element foliar nutrient sprays, products which contain humates, organic chelates etc.
There is interest in “organic” viticulture.
In areas with dry summers it is difficult to supply sufficient nitrogen to drip irrigated “organic” vineyards.