Biological and chemical attributes of soils under forest species in Northeast Brazil

Timber forests contribute to the sustainable development of the biomes in tropical regions.The aim of this study was to evaluate the biological and chemical properties of the soil as a consequence of the cover with native and non-native species in the Acarau basin,a transition area from the coast to the Brazilian semi-arid region.Areas planted with four native species(Anadenanthera colubrina,Astronium fraxinifolium,Handroanthus impetiginosus,Colubrina glandulosa)and three exotic species(Acacia mangium,Casuarina equisetifolia,Eucalyptus urophylla)plus a non-forested agricultural area were evaluated for organic carbon contents,and microbial and chemical soil properties.The levels of soil organic carbon were highest in A.colubrina and C.equisetifolia plantations.Low basal soil respiration was observed but the microbial biomass was particularly low in the non-forested area.In the C.equisetifolia,E.urophylla,and H.impetiginosus plantations,elevated soil metabolic quotients were found.The A.colubrina and H.impetiginosus plantations had the highest levels of easily extracted-glomalin related soil protein.Tree species affect concentrations of essential nutrients and the biological quality of the soil in different ways.They can also improve the biological and chemical properties of the soil in the coastal plains of tropical regions.