Physical Properties of Soil Structures Identified by the Profil Cultural under Two Soil Management Systems

Abstract

ABSTRACT Soil structure plays an important role in water retention, infiltration capacity, porosity, and penetration resistance. The aim of this study was to evaluate the unsaturated hydraulic conductivity and physical properties of Oxisol soils (bulk density and macro-, micro-, and total porosity) in the structures identified using the profil cultural method in areas under two different management practices (perennial pasture and sugarcane). Three pits were dug in each plot to find out how homogeneous morphological structural units (HMSU) were organized in the soil. Next, unsaturated hydraulic conductivity (Ki) was measured in situ inside each HMSU using a triple-ring infiltrometer at multiple suction. Six samples were collected (two samples for each kind of structural organization in each pit) to determine soil bulk density, total porosity, and macro- and microporosity. Each management practice resulted in a distribution of structures in the soil profile. The behavior of morphologically similar clods was the same, regardless of the physical manipulation of the soil. The distribution of structures based on the management practice determines specific hydraulic conductivities in the soil profile.

Keywords

• soil use
• compaction
• soil bulk density
• soil porosity