Effects of Phosphate Application on the Growth of Young Trees of Apple, Japanese Pear, Peach and Grape Growing on Volcanic Ash Soil

Effects of phosphate application on the tree growth, the flower bud formation and the nutrient content of young trees of apple, Japanese pear, peach and grape planted in the pots with allitic soil originated from volcanic ash were observed. 1. All of the trees which received no phosphate ceased to grow in early July and the symptoms of phosphorous deficiency appeared gradually. 2. Tree growth of apples, Japanese pears and peaches was remarkably promoted by the light application of phosphate which was equivalent to 2.5 percent of absorption coefficient of phosphoric acid of the soil, but it was promoted only slightly by the further applications. On the other hand, tree growth of grapes was little promoted by the light application of phosphate, but it was much promoted by the heavy application which was equivalent to 10 percent of the absorption coefficient of phosphoric acid of the soil. 3. The number of flower buds in peaches and Japanese pears increased in accordance with an increase of phosphate supply. 4. As the result of leaf analysis, it was found that N content decreased and P content increased with an increase of phosphate application in all species. K content in apples, Japanese pears andpeaches, and Mg content in grapes both increased with an increased application of phosphate. 5. Analyzing of phosphorous in various parts of the tree, it was found that effect of phosphate application on the P content was most conspicuous in leaf blades in apples, Japanese pears and peaches, but, in grapes, it was most conspicuous in petioles. 6. With an increase of phosphate supply, available phosphoric acid in the soil considerably increased, and absorption coefficient of phosphoric acid of the soil slightly decreased.Article信州大学農学部学術報告 9: 1-11(1965)departmental bulletin pape