Soil properties changing and carbon losses by anthropic drainage in savanna palm swamp (vereda), central Brazil

ABSTRACT In the Cerrado, the palm swamps ( veredas ) are characterized by being humid and stable environments that lead to the formation of Histosols ( Organossolos ). and soils with surface horizons of organic constitution, which are fragile and sensitive to anthropic action. This study aimed to evaluate the impact of anthropization (recurrent forest fires and livestock farming) on the chemical, physical and morphological properties of soils in two palm swamps in the Environmental Preservation Area (EPA) of Pandeiros River, Minas Gerais, namely: Água Doce, in preserved condition, and Taboa, in anthropized condition. Four soil profiles were morphologically described, two profiles in each palm swamp, with subsequent chemical and physical analyses, calculations of organic carbon stock and identification of the origin of organic matter. The results were analyzed using descriptive statistics and Pearson’s correlation coefficient. Soil morphological properties were influenced by vegetation cover, drainage and anthropization conditions. As for the physical and chemical properties, adequate values were observed in the preserved palm swamp, including lower bulk density values and higher cation contents. Anthropic actions in the anthropized palm swamp caused degradation of soils, revealed by subsidence, reduction in organic carbon content, increase in bulk density and decrease in fertility. Changes promoted in the soils of the palm swamps compromise ecosystem services, indicating that actions at either local or governmental level should be stimulated for the preservation and conservation of these environments.

摘要
在塞拉多（Cerrado）生态区内，棕榈沼泽（veredas）以湿润且稳定的环境为典型特征，这类环境可形成有机土（Histosols，葡萄牙语对应名称为Organossolos）以及具有有机组成表层的土壤，此类土壤结构脆弱，对人类活动干扰极为敏感。
本研究旨在评估人类活动（反复林火与畜牧养殖）对米纳斯吉拉斯州潘德罗斯河环境保护区（Environmental Preservation Area，简称EPA）内两处棕榈沼泽的土壤化学、物理及形态学特性的影响，两处沼泽分别为处于原生保存状态的Água Doce与受人类活动干扰的Taboa。研究人员对4个土壤剖面进行了形态学描述，两处沼泽各2个；随后开展了化学与物理分析、有机碳储量计算以及有机质来源溯源工作。本研究采用描述性统计与皮尔逊相关系数对试验结果进行分析。
土壤形态学特性受植被覆盖、排水条件及人类活动干扰程度的显著影响。就物理与化学特性而言，原生状态的棕榈沼泽土壤各项指标处于合理区间，表现为较低的容重与较高的阳离子含量。受干扰沼泽中的人类活动引发了土壤退化，具体表征为地表沉陷、有机碳含量降低、容重上升以及土壤肥力下降。
棕榈沼泽土壤发生的此类变化会损害生态系统服务功能，因此亟需推动地方或政府层面采取相关措施，以保护与保育这类湿地环境。