EUCALYPTUS-LEUCAENA MIXTURE EXPERIMENT. I. GROWTH AND YIELD

Abstract

The growth and yield of Eucalyptus urophylla and two varieties of Leucaena leucocephala (vars. K8 and K72) in pure stand and two-species mixtures were assessed over a seven year rotation. The experiment was established on moderately fertile soil in the humid/subhumid tropical climate of coastal Espirito Santo, Brazil in a randomized complete block design. Complete site preparation, fertilizer application and weed control further improved the site conditions for both species. At age 7 years, the eucalypts were all single-stemmed with an average height of about 20 m and dbh of 19 cm while the leucaena were multi-stemmed with an average height of 13 m and dbh of 9 cm per stem. Leucaena survival ranged from 95 to 100% while eucalypt survival was 75% when grown pure and only 50 to 65% when grown in mixture with leucaena. Yields varied between 31 and 46 m³/ha/yr, with maximum yield in the pure eucalypt treatment, intermediate yields in the two species mixtures and lowest yields in the pure leucaena treatments. Tables are presented of stacked and solid volume yields, dry matter biomass and charcoal production. It is suggested that on soils of good fertility and under fertilized conditions there is no advantage in terms of yield in growing leucaena and eucalyptus in mixture.