Biomass and nutrient biological utilization coefficient of Eucalyptus grandis x E. camaldulensis in different planting densities

Information about productivity and nutritional aspects has become increasingly necessary for successful conception and management of dense stands. The aim of this research was to evaluate the effect of initial plant spacing on biomass production and Biological Utilization Coefficient (BUC) of nutrients by a hybrid clone of Eucalyptus grandis x E. camaldulensis. The experiment was established in a randomized three blocks design. The treatments were: T1 - 3.0 x 0.5 m; T2 - 3.0 x 1.0 m; T3 - 3.0 x 1.5 m; T4 - 3.0 x 2.0 m and T5 - 3.0 x 3.0 m. A forest inventory was conducted at 101 months of age, with quantified biomass and BUC of nutrient calculated. Wood biomass estimates were 165, 159, 153, 147 and 134 t ha(-1) for T1 to T5, respectively. The variation range of trunk BUC was from 923 to 1174, from 7573 to 10450, from 948 to 1089, from 657 to 894, from 4807 to 6118 and from 2611 to 3497 kg of dry matter per kg of N, P, K, Ca, Mg, and S, respectively. It was concluded that the spacing influence on BUC of bark, wood and trunk of eucalyptus stands is different for nutrients. The denser spacing exhibited lower estimates of BUC for P and Mg in wood. The widest spacing presented the smallest BUC of S in wood and largest BUC of K in bark. Dense spacings have smaller stems and, when properly harvested at the technical cutting age, are more productive per unit of area.

Automated summary

This research aimed to evaluate the effect of initial plant spacing on biomass production and Biological Utilization Coefficient (BUC) of nutrients by a hybrid clone of Eucalyptus grandis x E. camaldulensis. The results showed that denser spacing had lower estimates of BUC for P and Mg in wood, while the widest spacing had the smallest BUC of S in wood and largest BUC of K in bark. Therefore, dense spacings are more productive per unit of area.