Contribution of natural soil compaction on hardsetting behavior

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• 作者：Fabiola ; Neyde ; Giarola ; Balarezo ; da Silva ; Alvaro Pires ; Imhoff ; Silvia ; Dexter ; Anthony Roger
• 关键词：Natural soil compaction ; Hardsetting soil ; Physical properties ; Micromorphological features
• 刊名：Geoderma
• 出版年：2003
• 出版时间：April, 2003
• 年：2003
• 卷：113
• 期：1-2
• 页码：95-108
• 全文大小：532 K

文摘

Many soils in tropical countries present genetically inherited compacted layers, which are commonly referred to as hardsetting. The occurrence of hardsetting is attributable to certain soil physical, chemical and mineralogical properties. We hypothesized that natural soil compaction contributes significantly to the occurrence of a hardsetting behavior in soils from Brazil. The aim of the study was to determine the effect of natural soil compaction on the occurrence of hardsetting horizons of a clayey Yellow Cohesive Latosol. This effect was analyzed: (a) in thin sections and microclods, by determining micropedological features, (b) in soil clods, by measuring tensile strength, and (c) in undisturbed samples, by determining the relationship between penetration resistance and effective stress. The analysis of thin sections and microclods revealed a denser particle packing for the hardsetting horizon. Tensile strength of the clods was significantly higher for the hardsetting horizon, probably due to higher packing of particles. For the variation in effective stress (σ′), the increment in penetration resistance (SS) was higher for the hardsetting horizon, which also had a higher bulk density (D_b). The natural soil compaction was the main factor that, directly or indirectly, influenced the physical and morphological properties analyzed and was responsible for the differences observed between non-hardsetting and hardsetting horizons, confirming the tested hypothesis.