The transformation of natural Amazonian environments into production systems, mainly related to agriculture and livestock, is considered the most frequent anthropic activity in the region, which can cause significant changes in physical attributes and soil organic carbon. On the other hand, the proper development of the plants depends basically on the quality of the soil, which is directly related to its attributes. Thus, the objective of this study was to evaluate the physical attributes and organic carbon of the soil in natural environments and in anthropic uses located in the southern region of Amazonas. Samples were collected at four spots in three depths (0.00–0.05 m, 0.05–0.10 m, 0.10–0.20 m), totalling 108 samples. The organic carbon has a positive correlation with silt, geometric mean diameter, weighted mean diameter and aggregates > 2 mm, and negative with soil and clay density. The environments with native forest 1, pasture and agroforestry are characterized by higher values of organic carbon, silt, geometric mean diameter, weighted average diameter and aggregates > 2 mm, while native forest 3, native forest 4 and açaí are characterized by higher values of clay and aggregates clay and aggregates between 2–1 mm and < 1 mm.

中文翻译：

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南亚马逊地区自然和人为环境下土壤的物理属性和有机碳

将亚马逊地区的自然环境转变为主要与农业和畜牧业有关的生产系统，被认为是该地区最频繁的人类活动，这可能导致自然属性和土壤有机碳发生重大变化。另一方面，植物的适当发育基本上取决于土壤的质量，这直接关系到土壤的属性。因此，本研究的目的是评估位于亚马逊河南部地区的自然环境和人类活动中土壤的物理属性和有机碳。在三个深度（0.00-0.05 m，0.05-0.10 m，0.10-0.20 m）的四个位置收集了样本，总共有108个样本。有机碳与泥沙，几何平均直径，加权平均直径和聚集体之间呈正相关> 2 mm，对土壤和粘土的密度为负。原生林1，牧场和农林业的环境具有较高的有机碳，淤泥，几何平均直径，加权平均直径和聚集体> 2 mm的值，而原生林3，原生林4和açaí的特征在于具有较高的黏土和骨料黏土和骨料在2–1 mm和<1 mm之间。