Nutrient Analysis
Soil analysis can be used to provide baseline initial information for a fertilizer programme.
Particularly as an indication of potassium and phosphorus requirements. It is also used to assess soil pH, and organic matter levels.
Tissue Analysis
Leaf tissue analysis, while rarely applied in cocoa, can be used to confirm that the balance between elements within an applied fertilizer programme is sufficient to support production. Tissue analysis will also confirm visible deficiency symptoms, and indicate any excessive nutrient concentrations which may be causing other nutrient imbalances or toxicities.
When assessing the nutrient content of nearly mature leaves, take the second or third leaf of the last maturing flush. Collect four or five leaves from across the tree canopy and sample at least 10 trees.
Do not include leaves that are damaged by insects or pests, or by mechanical injury. Reported sufficiency levels show a considerable variation between different authors and countries. This is most probably due to different sampling dates (wet/dry season), leaf age, shading and fruit load.
The tables below show leaf norms for macro and micronutrients. Both tables use the mean from all sources (calculated without the extremes) to give an adequate range. Refer to regional standards for details of local norms.
