Nutrient stock in the forest component in a crop-livestock-forest integration system in Central Brazil

Abstract

Integrated systems are sustainable alternatives, where agricultural, forestry, and/or livestock components occupy a given area through consortium, rotation, or succession. Considering this importance, this work had as objective to quantify the stock of above-ground biomass (wood, leaves, bark, and branches) of 6 years Eucalyptus urograndis in a crop-livestock-forest integration system (CLFS). It also involved calculation of the nutrient utilization in biomass conversion through the Biological Utilization Coefficient (BUC) and design of different export scenarios of these nutrients through the harvest in order to calculate the reduction in the demand for inputs. Nutrient stock was determined from the biomass sampled in the field and from the plant tissue analysis. It is verified that the highest concentrations of macronutrients are present in wood component, except for Ca. The concentration gradient of micronutrients was: Leaves> Fe> Mn> B> Cu> Zn; Branches and Bark: Fe> Mn > B> Zn> Cu; and wood: Mn > Fe > Zn > Cu > B. Considering BUC conversion rate decline, it presented the following order: S> P> Mg> Ca> N> K for macronutrients and B> Cu> Zn> Fe> Mn for micronutrients. The most appropriate export scenario was to harvest only timber component to minimize the nutritional export. The nutritional dynamics within the eucalyptus are altered according to the diametric structure of the trees. The nutritional elements are concentrated in different compartments according to the availability and need of the plants.