Effects of planting density on tree growth and vertical distribution of foliage and fruit on satsuma mandarin [Citrus unshiu] tree
1998
Tachibana, S. (Chiba-ken. Horticultural Experiment Station, Tateyama (Japan))
In 1967, two-year-old trees of "Miyagawa Wase", an early ripening satsuma mandarin, were planted in a clay loam soil under four different densities, D-1: 1,250, D-2: 2,500, D-3:5,000 and D-4: 10,000 trees/ha in 0.4 ha and grown for 16-22 years without thinning. Differences in annual increment of growth and yield between planting distances were recorded to determine when growth competition began. At the end of the experiment, trees were dissected to record the distribution of foliage and fruit and canopy structure of trees in high density plantings. The results were as follows: 1) differences in trunk girth, tree height and yield between a given tree density and the adjacent ones appeared in 5-6 years in D-4, 7-8 years in D-3 and 10-16 years in D-2. Hence, the higher the density, the sooner the differences were observed. 2) With respect to vertical distributions of the foliage as leaf area index (LAI) in Fig.7, D-1 had higher leaf density exceeding LAI 1 but at a lower elevation than that of D-2, whereas D-4 had higher leaf density at a higher elevation than D-3. A similar distribution of fruit per unit land area existed, i.e. most of the fruits were bone at the layers of higher leaf density. 3) In the yield per leaf area, D-2 was higher than D-1 and D-4 was higher than D-3 at the ground elevation where the foliage layers were exceeding LAI 1
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