Effects of long-term application of three major nutrients on the citrus trees growing in the orchard converted from a paddy field, 1: Growth, yield, and quality of Kiyomi and Iyo tangors top-grafted on satuma mandarin
1998
Matsuse, M. (Saga-ken. Fruit Tree Experiment Station, Ogi (Japan)) | Iwakiri, T. | Sindou, T. | Ono, T. | Yamaguti, M.
Effects of three major nutrients (N, P, K,) were investigated on the growth, yield, and quality of Kiyomi and lyo tangors, both of which were top-grafted in 1980 on satuma mandarin growing in the citrus orchard converted from a paddy field in 1965 (at Saga Fruit Tree Experiment Station). 1. The increase in plant capacity of Kiyomi in the non-fertilizer and non-N plots was about 70 % of the plants in the plot amended with the fertilizer of N, P, and K (200, 120, 160 kg each/ha/year). The plant capacity increase was the smallest in lyo tangor growing in the non-N plot. 2. The fruit yields of Kiyomi and of lyo tangors were the least in the non-fertilizer and non-N plots. Average fruit weight was the smallest in the non-K plot. No significant difference was recognized among all experimental plots for the sugar content (Brix-value) in fruit juice. Citric acid, content in Kiyomi fruit was the lowest of all in the non-K plot. Similar tendency was recognized for lyo fruit. 3. The contents of Pand K in leaves were almost proportional to the application treatments of these fertilizers. The effect of non-fertilization was more conspicuous for K than for P: the content of K in the non-K plot was less than 1/2 of the other plots. The specific K-deficiency symptom of lyo tangor occurred in the non-K plot. The magnesium (Mg)-deficiency symptom appeared both in Kiyomi and lyo tangors when the plants were not applied with P fertilizer containing Mg as an ingredient of the fertilizer used. This deficiency symptom was more significant in lyo than in Kiyomi: Mg content in lyo leaves was less than 0.25 %
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