Composition and functional soil properties of arenosols and acrisols: Effects on eucalyptus growth and productivity

Abstract

Linking edaphic properties to forest productivity provides significant gains in classification of site production potential. This study evaluated soil functional and composition properties that affect eucalyptus productivity in Acrisols and Arenosols, which represent two contrasting edaphic conditions and site productive potential capacity. Eucalypt stand growth, volumetric and biomass production data were related to the soil properties determined in undisturbed samples collected in 12 sampling points from seven soil layers, from the soil surface down to 1.20-m depth. Our results showed a volumetric wood production for 89-months-old stands of 422.3 m3 ha−1 (195.4 Mg ha−1; wood biomass) in Acrisols sites, and 288 m3 ha−1 (134.6 Mg ha−1; wood biomass) in Arenosols sites. Soil properties in Arenosols such as macroporosity and total porosity and soil bulk density (0.00-0.10 m layer) has positive and negative correlations, respectively, with eucalypt increment rates. In Acrisols, soil macroporosity, air permeability and saturated hydraulic conductivity in soil layers down to 0.60 m depth had positive correlation (p < 0.05) with forest productivity. Soil bulk density and air permeability in Acrisols affected more than 55% of variability in total height and biomass increment rates. Our results showed that forest productivity in soils with high water storage capacity is conditioned more by functional soil properties, particularly soil permeability to water and air, while in highly drainable soils forest productive capacity is conditioned by composition properties, such as soil porosity and soil bulk density.