為改進石柿果實品質，於新竹縣北埔鄉進行二試驗，試驗一調查50株石柿葉果比、果實大小與葉片養分，並分析其間相互之關係。石柿平均果重與葉片鉀含量及單株產量與果實數均呈顯著直線正相關；單株產量與葉果比呈顯著直線負相關，而與葉片磷含量呈極顯著二次負相關，與葉片鎂含量呈顯著二次負相關。試驗二利用疏果與除葉調整葉果比後，葉果比為20之處理可獲得較大之果重、果徑及果高，二年之平均果實重分別為104.5 g及88.64 g；小年時，以葉果比10之處理產量最高為25.9 kg plant^(-1)，大年時，以葉果比40之處理產量最高為62.3 kg plant^(-1)，而葉果比60之處理兩年產量均最低，且達5%顯著差異水準；各處理間葉片養分含量差異不大。從產量與單果重兩項因子考慮，石柿在大年時，於生理落果之後，將葉果比調整至20～40間，應可獲得較高之生產效益。
Two experiments were conducted in Hsinchu county to improve fruit quality of persimmon by adjusting leaf fruit ratio. The yield, fruit characters and leaf nutrients content of fifty 'Shi' persimmon plants leaf were investigated and analyzed in the first experiment. There had significantly positive linear correlation between average fruit weight and leaf potassium content, and yield of per plant and number of fruit. Yield was negatively linear correlated to leaf fruit ratio, and negatively correlated to leaf phosphorus and magnesium content. Leaf fruit ratio was adjusted in the second experiment by thinning and removing leaves. Plants which maintain the leaf fruit ratio under twenty gave the highest fruit weight, fruit latitude and fruit diameter. The average fruit weight were 104.5 and 88.64 g in 2003 and 2004 respectively. Plants which maintain the leaf fruit ratio under ten gave the highest fruit yield (25.9 kg plant^(-1)) at 2003 (off year). Plants which maintain the leaf fruit ratio under forty gave the highest fruit yield (62.3 kg plant^(-1)) in 2004 (on year). Treatment, maintain the leaf fruit ratio under sixty, had the lowest fruit yield both in 2003 and 2004. There had no significant difference on leaf nutrients content among treatments. According to yield and fruit weight factors, we should adjust the leaf fruit ratio of 'Shi' persimmon from 20 to 40 to obtain high production efficiency.
