A balancing act in soil

For the Cook Islands to achieve optimum nutritional value in their fruit and vegetables and thereby ensure top prices for their produce, it is essential to achieve a balanced composition of chemicals and trace elements in soils.
Secretary for Agriculture Anthony Brown who is also a grower and member of the Titkaveka Growers Association, says regular soil tests are a key factor in determining the health of the soil. At specific occasions certain chemicals need to be applied to ensure firstly, strong growth then strong fruiting.
In September last year, Brown had the soil in two of his plots, one in watermelon and the other in cucumber, tested. The sampling was done by soil scientist Dr Eric Kawabe of Eric Kawabe and Associates Ltd who are based in Rotorua, New Zealand.
The tests were carried out by USA based testing laboratory Brookside Laboratories Inc. The reason being there is no lab in NZ capable of testing the biological activity in soil. The two tests cost $150 each and it took just two weeks to get the results back.
Kawabe’s report and analysis of corrective action to be taken arrived in November.
The report showed Brown that while his two plots were situated some distance apart, the tests produced almost identical results. Four substances including Calcium and Sulphur and trace element Boron were well below optimum level while five substances well exceeded optimum level. Three substances were at or just below optimum level.
Based on these results, Dr Kawabe was able to prescribe for Brown the corrective action he needs to take to achieve a balance of substances in his soils. As regards various chemicals and trace elements, he has told Brown how much in terms of kgs he needs to apply by the hectare and square metre.
So how did Brown’s soils stand up? Dr Kawabe’s daughter Ottilie Kawabe Upshall is a soil scientist and consulting Agronomist. She has provided Brown with a number of recommendations concerning the deficiencies in his soils. For instance she has advised that his soil is slightly acidic with a low level of organic matter. Sulphur is deficient while phosphorus is adequate. Magnesium is excessive and Calcium deficient while Sodium and Potassium are sufficient. Of the trace elements, she reports Boron is insufficient while Zinc and Manganese are sufficient and Copper is excessive. Some Nitrogen is needed.
Upshall recommends annual testing at the same time each year to monitor progress and adjust treatments accordingly.
Brown advises that a grant of $6,000 has been secured to have soils in all farms in Titikaveka tested.

Herald Issue 463 10 June
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