Land use regulates microbial biomass and activity in highly degraded soil from Brazilian dry tropical forest

Tropical dry areas in Brazil cover approximately 1 million km(2) and are significant contributors to soil carbon (C) loss to the atmosphere. This study is part of a large project that has evaluated the effects of land cover type variation on chemical and biological attributes in a reference area of the Brazilian semi-arid region. Five different land cover types were selected: native forest, Tabebuia alba (Ridley) Sandwith, Anadenanthera falcata Benth forest, secondary scrub regeneration and agricultural no-irrigation maize. Different types of land use influenced soil variables mainly in the superficial layer. Soil organic carbon (SOC) reduced to 73% of native forest in agricultural no-irrigation maize and 76% in secondary scrub regene for dry seasons. Reforestation management with T. alba or A. falcata showed positive effects on soil quality with high levels of SOC and labile fractions in both the dry and rainy seasons. Our data affirm the importance of more sustainable management practices for soils under dry tropical forest since these areas exhibit slow recovery of SOC and microbiological attributes. Thus, we recommend reforestation of dry tropical areas with T. alba and A. falcata aiming to improve the health and sustainability of degraded soils.