აზოტიანი სასუქების ფორმების გავლენა მანდარინის მცენარის პოლარობის კოეფიციენტზე

Abstract

Previous studies showed that by analysing leaves in different parts of the crown it was possible to determine the relationship of the content of a given nutrient between leaves in the upper and lower parts of the crown, and to use this relationship (polarity coefficient) as an index of nutrient status of the plant. The possibility of applying this diagnostic method to satsuma trees, receiving N only, was investigated. Five different N fertilizer forms were applied, 60% before flowering in early Apr. and 40% after flowering. The total N and polarity coefficient were determined in the 1st, 3rd and 5th leaves for 13-year-old trees in the five N variants, in the control trees (no fertilizers) and in those receiving PK + Ca basal dressing only. The data are tabulated. The leaves of trees fertilized with urea + basal dressing contained less N than leaves in all other treatments, and this was reflected in the highest yield (56.3 kg/tree) compared with 26.8 kg/tree in the control and 34.5-44.8 kg/tree in other treatments. In all N treatments the polarity coefficient was <1.0.