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Fertilising

Olives are grown in a variety of soils and conditions. Therefore customised management of tree nutrition is required.

The four tools for optimal nutrient management are:

• Observation of trees and environmental conditions.
• Soil and water analysis.
• Leaf analysis.
• Recording.

Observation

Visual symptoms should be used as an aid to interpreting soil and leaf analyses:

• Look for abnormal symptoms in foliage or growth.
• Look for significant variations in yield.
• Observation can suggest deficiencies of:

• • nitrogen,
  • potassium, and
  • boron.

Leaf Analysis

Initial leaf analysis should be undertaken when the trees are two years old, then on a regular basis. A standard analysis will cost approximately $70.

• Summer (January) is the best time to undertake leaf tissue analysis.
• Levels of most nutrients stabilise in the olive leaf during January and February.
• Standards for optimum leaf nutrient concentrations are given in The Olive Handbook.
• For the analysis:

• Remove 4 mature leaves per tree from the middle of current season non-bearing shoots from 25 trees.
• Trees should be of similar size and on a single soil type.
• Different samples should be taken for widely differing soils.
• Wrap leaves in paper bags or newspaper, NOT plastic or other material which will make them sweat.

• If testing for Boron, mature fruit samples may be more reliable than leaf samples.

Soil and Water Analysis

• Soil and water analysis should be undertaken during site selection and deficiencies rectified during site preparation.
• This should be followed by continuous analysis at two-year intervals.
• Reliable standards for soil mineral nutrients for fruit trees are lacking so analysis should be considered in conjunction with leaf analysis.
• A standard soil analysis should provide information on the following soil conditions and nutrients and will cost approximately $70.

• pH - indicating soil acidity
• salt - indicating salinity levels
• moisture
• organic carbon
• total nitrogen %
• phosphorus %
• potassium %
• sulphur %
• calcium %
• magnesium %
• copper mg/kg
• zinc mg/kg

FERTILISER APPLICATION

• Spreading fertiliser well beyond the root zone is a waste.
• Cover the entire present root zone.
• Extend slightly beyond root zone to allow for new growth.
• Generally, the diameter of the root zone is @ 2-3 x the foliage area.
• The following table suggests nitrate application for spring plantings:

Year	Month	Ammonium Nitrate per Tree	Root Zone Diameter
1	Oct/Nov/Dec	42gm	0.6m
1	Jan	50gm	0.9m
1	Feb	50-63gm	1.2m
2	Aug	85gm	1.8m
2	Nov	110gm	2.1m
2	Feb	120gm	2.7m
3	Aug	125gm	3.4m
3	Nov	140gm	3.7m
3	Feb	150gm	4.3m
4	Apply fertiliser in response to leaf and soil analysis.