Physical Quality of a Typic Hapludult Soil Under Forest Leguminous Trees and Pasture

ABSTRACT Revegetation with leguminous trees has been used to recover degraded areas. This study aimed to evaluate the physical quality of a Typic Hapludult soil under secondary forest, pasture and three leguminous tree species: Acacia (Acacia auriculiformis), Sabia (Mimosa caesalpiniaefolia) and Inga (Inga spp. ), in Conceição de Macabú County, Rio de Janeiro State, Brazil. Soil samples from the 0-0.10 m and 0.10-0.20 m layers were collected and analyzed in July, 2015. Lower bulk density and higher total porosity and macroporosity values occurred under forest. The higher microporosities were associated with higher bulk densities and lower values of total porosity and macroporosity (pasture and Acacia). The soil under pasture, even when compacted, preserved the largest amount of mesopores, perhaps due to the fasciculate root system of these plants. It was concluded that revegetation leads to changes in the soil surface layer so that its physical attributes become similar to those found in the forest and differ from those of pasture, with an increase in quality to support forest ecosystem functioning.摘要 利用豆科乔木开展植被恢复，是退化区域生态修复的常用手段。本研究以巴西里约热内卢州孔塞桑-迪马卡布县内，次生林、牧草地以及金合欢（*Acacia auriculiformis*）、萨比亚（*Mimosa caesalpiniaefolia*）、印加树属（*Inga spp.*）3种豆科乔木林下的典型强发育湿润老成土（Typic Hapludult）为研究对象，旨在评估其土壤物理质量。研究于2015年7月采集0~0.10 m与0.10~0.20 m土层的土壤样品并进行分析。结果显示，次生林下土壤容重更低，总孔隙度与大孔隙度更高。牧草地与金合欢样地的微孔隙度更高，同时伴随更高的容重与更低的总孔隙度、大孔隙度。牧草地土壤即便处于压实状态，仍保留了最高的中孔隙含量，这或许与该类植物的束状根系有关。研究表明，豆科乔木植被修复可改变土壤表层的物理属性，使其趋近于次生林的土壤物理特征，与牧草地的土壤物理性质产生显著差异，同时提升了支撑森林生态系统运转的土壤质量。