Atmospheric nitrogen (N)-fixing tree species provide numerous benefits for the soil. The of thisstudy was to evaluate the effect of soil management on root development and growth of trees in mixed standsof Eucalyptus urograndis (Eucalyptus urophylla S. T. Blak and Eucalyptus grandis W. Hill ex Maiden) andAcacia mangium Willd. These species were established in a randomized block design with split plots,subjected to minimum tillage and intensive tillage, monospecific stand of Eucalyptus urograndis (1) andAcacia mangium (2), in addition to the intercropping of these species with 50% of the density of thecompound compartment of each species (3). Increments in diameter and height were measured up to 49months after installation of the experiment and fine roots (<2 mm in diameter) were sampled at five differentpoints in two sets of trees per plot up to 1.0 m depth (0-0.1, 0.1-0.3, 0.3-0.5, 0.5-1.0 m) using a steel probewith 0.045 m internal diameter. After 49 months, E. urograndis trees showed greater increments in height anddiameter. Treatment 2 showed a higher fine root density (FRD) in all layers. The implementation of mixedstands intensified the FRD of E. urograndis in the 0-0.1 m layer. Effect on root development was observedonly in the 0.1-0.3 m layer, where intensive tillage increased FRD in treatment 2. Thus, mixed stands can bean excellent alternative for forest production in areas subjected to soil degradation.
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