Chemical Attributes and Carbon Fractions in Serra de Itabaiana National Park

Abstract This study aimed to assess soil chemical attributes, organic matter fractions and carbon stocks of forest in three different regeneration stages in the Serra de Itabaiana National Park, Sergipe. The study was conducted in three areas: open white sands, intermediate white sands, and closed white sands, with a history of differentiated degradation. Soil samples were collected at 0-20 cm depth for chemical characterization and for fractionation of soil organic matter and C stock. The open white sands obtained the best results regarding levels of macronutrients, total organic carbon, and total soil nitrogen, as well as higher carbon/nitrogen ratio compared with intermediate white sands and closed white sands, with such effects being attributed to recent exposure to fire. Carbon concentrations in humic fractions of organic matter were little influenced by different vegetation in regeneration, except the carbon fraction of humic acid, which is more sensitive to different management and soil usage.摘要 本研究旨在评估巴西塞尔希培州伊塔巴亚纳山脉国家公园内三个不同更新阶段森林的土壤化学属性（soil chemical attributes）、有机质组分（organic matter fractions）及碳储量（carbon stocks）。本研究选取三类研究区域：开阔白砂地、中度白砂地与密闭白砂地，各区域均存在差异化退化历史。于0~20 cm土层采集土壤样品，用于开展土壤化学表征、有机质组分分级及碳储量测算。相较于中度白砂地与密闭白砂地，开阔白砂地的大量营养元素（macronutrients）含量、总有机碳（total organic carbon）及土壤全氮（total soil nitrogen）水平均更优，且碳氮比（carbon/nitrogen ratio）更高，该效应归因于其近期遭受过火扰动。有机质腐殖质组分（humic fractions）的碳浓度受更新阶段植被差异的影响较小，仅腐殖酸（humic acid）碳组分对不同管理措施与土壤利用方式更为敏感。