Effects of Applications of Nitrogen, Phosphate and Potash on Growth, Yield and Quality of the Nijisseiki Pears Growing on Volcanic Ash Soil

Effects of applications of nitrogen, phosphate and potash on the tree growth, the yield, the fruit quality and the leaf composition of Nijisseiki pears planted in the large pots with volcanic ash soil were observed. 1. On the tree growth, applications of nitrogen were most influential and those of phosphate were more influential than those of potash. 2. On the flower bud formation, responses to nitrogen and phosphate applications were very conspicuous. Potash applications showed a tendency to increase the fruit weight. 3. The intensity of yellow color on the fruit surface decreased with an increase of nitrogen supply. The luminosity of the fruit color decrease with increased applications of potash. The heavy application of potash resulted in high fruit firmness. 4. The sugar content in the fruit juice slightly decreased with increases of nitrogen and potash supply. The acid content in the fruit juice was significantly reduced by phosphate applications and it was significantly increased by potash applications. 5. The contents of N and Mg in the leaves were increased but the contents of P and K in the leaves were decreased as a result of increased applications of nitrogen. By phosphate applications, the contents of P, Ca and Mg in the leaves were increased but content of K was decreased. Applications of potash resulted in an increase in the content of K and a decrease in the contents of N and Mg in the leaves. 6. It was found that the acid content in the fruit juice was correlated negatively with the K content in the leaves and it was correlated positively with the P content in the leaves.Article信州大学農学部学術報告 9: 13-22(1965)departmental bulletin pape