GENESIS AND CHARACTERISTICS OF SOILS OF THE SANTANAMOUNTAIN RANGE IN THE SERIDÓ REGION, RIO GRANDE DO NORTE, BRAZIL

ABSTRACT Rio Grande do Norte has mountain formations with edaphoclimatic conditions different from those predominating in the state, presenting deeper,acid soils, and milder climate. Among these formations, is the Santana mountain range, which is part of the Serra do Martins Formation. The objective of this work was to interpret the pedogenesis of the representative soils of the Santana mountain range through morphological, physical, and chemical characterizations of soil profiles and evaluate the effect of these attributes on the distribution of pedological forms along the landscape using multivariate analysis. Morphological, physical, and chemical analyses of seven soil profiles of the Santana mountain range were performed. The soils were classified according to the Brazilian Soil Classification System and the data subjected to multivariate analysis. The representative soil classes found were: LATOSSOLO AMARELO Distrófico argissólico; LATOSSOLO AMARELO Eutrófico argissólico; NEOSSOLO QUARTZARÊNICO Órtico típico; NEOSSOLO LITÓLICO Eutrófico fragmentário; NEOSSOLO REGOLÍTICO Eutrófico típico and CAMBISSOLO HÁPLICO Tb Eutrófico léptico. According to the analysis of the morphological attributes, the parent material had great influence on the formation of the different soil classes found in the Santana mountain range. The soil textural classes varied from sand to sandy clay loam. According to the analysis of the chemical attributes, the soil profiles presented acid reaction, great variation of base saturation, and low electrical conductivity. The multivariate analysis established groups of representative soil profiles of the Santana mountain range through the distinction of their physical and chemical attributes, mainly of subsurface diagnostic horizons.

摘要：北里奥格兰德州（Rio Grande do Norte）存在与全州主导土壤气候条件迥异的山地构造区域，其土壤更为深厚且呈酸性，气候更为温和。其中圣安娜山脉（Santana mountain range）隶属于马丁斯山脉地层组（Serra do Martins Formation）。本研究旨在通过对土壤剖面的形态学、物理学与化学特征表征，解析圣安娜山脉典型土壤的成土作用，并借助多变量分析方法，探究这些土壤属性对景观内土壤形态分布的影响。本研究对圣安娜山脉的7个土壤剖面开展了形态学、物理及化学分析，依据巴西土壤分类系统（Brazilian Soil Classification System）对供试土壤进行分类，并对所得数据进行多变量统计分析。本研究鉴定得到的典型土壤类别包括：贫养黏化黄色砖红壤（LATOSSOLO AMARELO Distrófico argissólico）、富养黏化黄色砖红壤（LATOSSOLO AMARELO Eutrófico argissólico）、典型正常石英砂质新成土（NEOSSOLO QUARTZARÊNICO Órtico típico）、富养碎屑状岩性新成土（NEOSSOLO LITÓLICO Eutrófico fragmentário）、富养典型母质新成土（NEOSSOLO REGOLÍTICO Eutrófico típico）以及富养薄积层简育雏形土（CAMBISSOLO HÁPLICO Tb Eutrófico léptico）。形态学属性分析结果表明，母质对圣安娜山脉各土壤类别的形成具有显著影响。供试土壤的质地等级范围为砂土至砂质壤土。化学属性分析结果显示，供试土壤剖面呈酸性反应，盐基饱和度差异显著，电导率较低。多变量分析依据土壤的物理与化学属性（主要为下层诊断层特征）对圣安娜山脉的典型土壤剖面进行了聚类分组。