Long-Term Land Use Impacts on Near Surface Soil Physical Properties.

Soil processes and properties are affected by long-term land use and management.  The physical alteration of soil properties due to long-term land use and management can impact soil structure which is important for mass and energy transport in soil. These soil properties and processes influence the soil temperature and moisture regimes.  The most noticeable changes in soil properties due to long-term land use and management include soil organic matter content, soil bulk density, soil porosity, hydraulic conductivity, and soil water retention.  Therefore, the known capacity of long-term land use and management to alter soil physical properties necessitate detailed investigations of their effects on soil physical properties and is essential for developing best land management practices.  Therefore, the objective of this study is to examine how long-term land use and management practices on the same soil affect near surface soil physical properties.  Near surface soil physical properties under the following long-term land uses (> 20 years) are examined:  crop land, short-rotation sweetgum (Liquidamber styraciflua L.) plantations, switchgrass (Panicum virgatum L.) bioenergy crops, and pasture. Soil samples are collected from an overall depth of 0 – 15 cm in 5 cm depth increments and the following soil properties are measured: soil organic matter content, saturated hydraulic conductivity, bulk density, soil water retention, and pore size distribution. Analysis of variance (ANOVA) is performed to determine and report the differences in near surface soil physical properties among the different land uses.