INFLUENCE OF CHLORINE ON SHOOT GROWTH OF KIWIBERRY (ACTINIDIA ARGUTA (SIEB. ET ZUCC.) PLANCH. EX MIQ.)

Abstract

Actinidia species show a relatively high uptake of N, K, Cl and Ca. Nitrogen is an important nutrient for good cane growth, but too much nitrogen causes excessive vegetative growth, poor yields, and increased winter injury. Applications of nitrogen at the end of the fruiting season enhance fruit size but are discouraged as fruit then tend to store poorly. Special attention should also be paid to boron (B) and sodium (Na) as the kiwifruit is extremely sensitive to excess of both elements in the soil. Actinidia deliciosa needs comparatively high concentrations of chloride for optimum growth. Therefore, unless the natural soil is high in Cl (>150 mg/kg) and/or low in N, K should be preferably applied as KCl. K is more readily absorbed by kiwifruit in its chloride form than as sulfate. Yield differences up to 30% have been recorded in relation to the chloride content of the soil. Until now there were only few studies examining chlorine effects and content in Actinidia arguta. Some experiments with young plants in pot culture were performed. The vegetative plant parts were analyzed to study the effects of chloride on the growth and development of 3 cultivars ('Jumbo', 'Ken's Red' and 'Maki'). The results clearly show that also this species has a great demand of chloride for optimal growth.