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Luis Eduardo Akiyoshi Sanches Suzuki, José Miguel Reichert, Dalvan José Reinert, Cláudia Liane Rodrigues de Lima, Degree of Compactness and Mechanical Properties of a Subtropical Alfisol with Eucalyptus, Native Forest, and Grazed Pasture, Forest Science, Volume 61, Issue 4, August 2015, Pages 716–722, https://doi.org/10.5849/forsci.14-172
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Degree of compactness (DC) is a useful parameter to evaluate management effects on soil structure and crop growth and development. We used DC in soil structure evaluation in a Typic Paleudalf with the following land uses: (1) native disturbed forest with undergrowth of shrub species; (2) 5-year-old pasture; (3) 20-year-old Eucalyptus saligna stand (eucalyptus 20); and (4) 4.5-year-old, second-rotation Eucalyptus saligna stand (eucalyptus 4.5). We determined soil bulk density (BD), porosity, saturated hydraulic conductivity, and reference bulk density (BDref) of compacted soil at −33 kPa matric potential compressed at 200, 400, 800, and 1,600 kPa (respectively, 29, 58, 116, and 232 psi) loads. DC was calculated as the ratio between field BD and BDref at 200, 400, 800, and 1,600 kPa until a DC (using BDref at 1,600 kPa) of 75% soil microporosity increases and then decreases with a further increase in compactness. BD and BDref depend directly on clay content, but their ratio, DC, depends only indirectly on soil texture. DC is affected by land use and varies with soil depth: in pasture, compaction caused by animal trampling is more pronounced in the layer 0.00–0.10 m, whereas in eucalyptus 4.5 harvest in first-rotation DC increases until the 0.40 m soil depth. For eucalyptus and native forest, the layer 0.00–0.10 m shows low DC associated with high organic matter, biological activity, and roots.
