RESPONSES OF 'FUYU' PERSIMMON TO K FORMS AND FERTIGATION RATES ON TREE GROWTH AND FRUIT QUALITY

Persimmon growers in the southern part of Korea have used KCl or K₂SO₄ as a source for supplemental K fertilization in summer. This study was conducted to compare the effects of the two K forms on soil chemical properties, tree growth, and fruit quality. They were fertigated at two rates to pot-grown ‘Fuyu’ persimmon trees from June to September for four years from 2005 to 2008. After four years of treatments, chemical properties of the pot soil did not change noticeably, nor did the K forms significantly affect K concentration in fruits, leaves, and shoots. In the last year of experiment, the number of flower buds, leaf growth, and trunk cross-sectional area were not significantly affected by the K forms and the rates. Fruits were significantly larger with better coloration for the KCl in 2005 and 2006, but such an effect was not found in 2007 and 2008. K rates did not change fruit characteristics except for soluble solids that significantly increased for the lower rate in 2007 and 2008. Results indicated that either KCl or K2SO4 would be acceptable as a supplemental K source.