Expert Says Excessive Use of Fertiliser Pushes Up Costs.

Byline: Somporn Thapanachai

Jul. 27--Fruit growers should analyse nutrient levels in the soil and in fruit leaves to work out the most suitable fertiliser formula, according to an expert.

As most orchardists do not know the precise needs of their trees, they overspend on fertiliser by providing all three basic formulas just to be on the safe side, according to Associate Professor Jingtae Siripanich of the Thailand Research Fund.

Dr Jingtae said that as many growers applied fertiliser as instructed by chemical distributors the cost of growing fruit was higher than necessary. As well, incorrect application could create toxins and interfere with the tree's ability to absorb nutrients.

Prapatpong Vejjajiva, who owns a 300-rai durian orchard in Chanthaburi province, said that he started his business in 1960 and for the past 40 years had always applied potassium phosphate, based on traditional knowledge that trees need phosphate before flowering.

"I didn't realise that my orchard has 10 times more phosphate than is necessary until I sent soil and leaves to be examined," Mr Prapatpong said.

After that he turned to other types of ...