Atributos dos horizontes diagnósticos superficiais em solos sob influência de reflorestamento em região de clima semiárido

Abstract

Forest species can progressively modify edaphic and pedogenetic attributes of surface horizons through organic matter accumulation. Recognizing the importance of forest soils for timber production in the furniture industry, this study examined the effects of different forest covers on pedological dynamics in surface horizons of a Gray Argisol within the Coastal Tablelands furniture production hub of Baixo Acaraú, Ceará State. The research specifically evaluated whether eleven years of differentiated organic matter input from native and exotic species could alter surface diagnostic horizon classification.The experimental design employed randomized blocks with two replicates, comparing areas planted with native species - pink trumpet tree (Tabebuia impetiginosa) and sobrasil (Colubrina glandulosa) - against exotic species - acacia (Acacia mangium) and eucalyptus (Eucalyptus urophylla) - with a fallow control area. Comprehensive analyses included morphological, physical, chemical, and microbiological assessments of A1, A2, and EA surface horizons, along with quantitative and chemical characterization of litter and spontaneous vegetation. Data underwent variance analysis, Box-Cox power transformation, and multivariate methods. Results indicated that while all vegetation covers modified soil attributes, native species - particularly pink trumpet tree - created the most favorable edaphic conditions. This treatment enhanced structural aggregate development (moderate aggregation in A1 horizon) and intensified soil darkening (10YR 4/1 moist color). Chemically, it improved fertility through increased exchangeable bases (K⁺, Ca²⁺, Mg²⁺), base saturation (≤50%), and optimal C/N ratio (11.15) promoting organic matter mineralization. Contrastingly, eucalyptus showed minimal K⁺ (0.06 cmolc dm⁻³) with higher acidity, while acacia exhibited elevated aluminum saturation. Microbial activity (33 mg C-CO₂ 50 cm⁻³ basal respiration) confirmed superior litter quality under pink trumpet tree. Litter deposition patterns revealed seasonal variation: dry periods showed no significant organic input differences, but rainy seasons demonstrated reduced litterfall in native species versus eucalyptus's dominant foliar contribution. The fallow system displayed intermediate chemical characteristics without structural improvements. Despite these modifications, all treatments maintained A moderate horizon classification, suggesting eleven years insufficient for profound pedogenetic changes. However, results emphasize native species' potential - particularly pink trumpet tree - for soil quality improvement, with important implications for sustainable forest management in coastal sandy soils. The study underscores the necessity of extended timeframes and adaptive practices for significant diagnostic horizon transformations.