Production and distribution of dry matter in trees of Coffea arabica L. in Kenya as affected by seasonal climatic differences and the presence of fruits

摘要: SUMMARY Standard growth analysis procedures were used to study the production and distribution of dry matter in 3 1/2 5-year-old coffee trees through their first into second commercial fruiting year. The growing field treated according normal practice. Up fifteen deblossomed harvested on each seven occasions, at intervals 63–90 days. weights four aerial fractions, five root fractions all fallen, picked pruned material recorded. The net assimilation rate (E) was as large that recorded East Africa for seedlings (0·13 g dm-2wk-1). Fruiting increased weight faster than trees, even when leaf area 30% smaller. Their E up 0·19 dm-2wk-1when expressed a basis 0·16 dm-2wk-1even total green fruit surface included calculation. In hot, season, January–February 1968, parts relatively slowly, except thin roots (< mm diameter) which, this took about 10% increment. had been December only 0·09 dm-2wk-1. Flushes shoot occurred beginning Long Rains 1967 1968 (February–March). During flush, 61% increment new, leaves with mean specific over 140 cm2g-1. 10 % increment, but thicker very slowly. branches trunk extended rapidly, radial slow. Following flushes, ratio (0·38 dm2g-1in 1967) during (April–June 1967, 1968), conditions favourable photosynthesis (E 0·13 dm-2wk-1), although little Leaf decreased owing decrease (in 1967: 118 95 cm2g-1). Pruning carried out June new cool, July mid-September, slow. Consequently, increase season small, dm-2wk-1. leaves, which 33 further (to 83 cm2g-1) most ones taking 17 increment. Light did not affect seasonal periodicity described. Both light heavy tended, eventually, lessen proportionately more thick roots. In retained 8000 fruits per tree, 70 Rains, became 36 trees' weight. Some rootlets these weight. Aspects productivity, are discussed, some management implications noted.