ISHS Acta Horticulturae 448: III International Symposium on Mineral Nutrition of Deciduous Fruit Trees
EFFECT OF NPK FERTILIZATION ON CLEMENTINE GROWN IN ALGERIA |
| Author: | R. Dris |
| Keywords: | Citrus reticulata Blanco, ‘Citrange troyer’, Poncirus trifoliata, leaf diagnosis, rootstocks, soil analysis, yield, NPK Fertilization, clementine |
| Abstract:
NPK fertilization of clementine (Citrus reticulata Blanco) was studied in northern Algeria in a field trial planted in 1974. Trees were grafted on ‘Citrange troyer’ (CT) and Poncirus trifoliata (PT) rootstocks. Experimental plots consisted of four trees, the 2 PT's and 2 CT's diagonally opposed. From 1980 to 1990, the annual NPK fertilization was given as ammonium nitrate (N 33%), superphosphate (P 20%) and potassium sulphate (K 48%). The major nutrient fertiliser combinations available were the following: N1P2K2, N2P1K1, N2P1K2, N2P2K1, N3P1K2 and N3P2K2 where N1 = 300, N2=600, N3=900; P1=150; P2=300; K1=300; K2=600 g.tree-1.year-1. During the period of fruit development in 1989, the mean values of leaf nitrogen, phosphorus and potassium and ratios N/P and K/P in branches without fruit were slightly higher than in the fruiting ones. Mean nitrogen and potassium concentrations and nutrient ratios N/K, N/P and K/P were higher in leaves of PT trees. Nitrogen and potassium concentrations in the leaves were inadequate. Over the period 1986–1990, the average annual yield of trees grafted onto CT and PT were 122 and 108 kg.tree-1, respectively. Treatment N2P1K2 gave the highest annual average yield. At the N2P1 level, duplication of the potassium dosage increased the yield. | |
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