PEDOGENESIS ON COASTAL TABLELANDS AREA WITH LOW RANGE ALTIMETRY IN PARAÍBA STATE

• Published in: Caatinga 2019-06, Vol.32 (2), p.458-471
• Main Authors: SILVA, GIVANILDO ALVES DA, CAMÊLO, DANILO DE LIMA, CORRÊA, MARCELO METRI, SOUZA JÚNIOR, VALDOMIRO SEVERINO DE, RIBEIRO FILHO, MATEUS ROSAS, ARAÚJO FILHO, JOSÉ COELHO DE
• Format: Article
• Language: eng ; por
• Subjects: Acid digestion; AGRICULTURE, DAIRY & ANIMAL SCIENCE; AGRONOMY; Altimetry; Aluminum; Ammonium; Bicarbonates; Chemical analysis; Citric acid; Classification; Clay; Clay minerals; Dithionite; Drainage; FISHERIES; FOOD SCIENCE & TECHNOLOGY; FORESTRY; Iron; Optical density; Oxalic acid; Podzolic soils; Runoff; Sand; Sediments; Silicon; Sodium; Sodium citrate; Sodium pyrophosphate; Soil classification; Soil formation; Soil investigations; Soil profiles; Soil properties; Soil sciences; Soils; Subgroups; Sugarcane; Sulfuric acid; Surface layers; Surface runoff; VETERINARY SCIENCES
• ISSN: 0100-316X; 1983-2125; 1983-2125
• DOI: 10.1590/1983-21252019v32n219rc

ABSTRACT Small variations of relief may change drainage and runoff and hence promote the formation of sandy surface horizons and hardened subsurface horizons (fragipans and/or duripans) in Coastal Tablelands soils. This study aimed to investigate the pedogenesis on Coastal Tablelands area with low range altimetry in Paraíba state; secondly, we also sought to contribute to the improvement of the Brazilian Soil Classification System (BSCS). Four soil profiles ware described and collected to be submitted to routine physical and chemical analysis, determination of Fe, Al and Si extracted by sulfuric acid digestion, sodium citrate-bicarbonate-dithionite and acid ammonium oxalate, sodium pyrophosphate, and mineralogical analysis in the sand and clay fractions by X-ray diffractometry. Optical density of the oxalate extract (ODOE) was also determined; the results were statistically evaluated using the R software. Microrelief variations conditioning differentiated water flows, along with the sandy texture of the surface horizons (A and E) and the lower coarse sand/fine sand ratio in the subsurface horizon, seem to promote clay accumulation in depth in the Spodosols developed on Coastal Tablelands environments. For this soils, the argilluvic (argissólico) character at the subgroup level of the BSCS should be incorporated. In addition, Al amorphous mineral phases and/or poorly crystalline play an important role in the formation of strongly cemented horizons (duripans) of the Spodosols, as also reported by other authors. Finally, the ODOE showed to be an efficient indicator of soils under podzolization process, being possible its use as a taxonomic criterion for classification of Spodosols by the BSCS. RESUMO Pequenas variações de relevo influenciam na drenagem e no escoamento superficial, contribuindo para a formação de horizontes superficiais arenosos e subsuperficiais endurecidos (fragipãs e, ou, duripãs) em solos dos Tabuleiros Costeiros. Este trabalho investigou a pedogênese em área de Tabuleiros Costeiros com baixa amplitude altimétrica no Estado da Paraíba; secundariamente, buscamos contribuir para o aprimoramento do Sistema Brasileiro de Classificação de Solos (SiBCS). Quatro perfis de solos foram descritos e coletados para a realização das análises físicas e químicas de rotina, extrações de Fe, Si e Al por digestão sulfúrica, por ditionito-citrato-bicarbonato de sódio, por oxalato ácido de amônio e por pirofosfato de sódio, e as análises mineralógicas das fra