Conceptual framework for capacity and intensity physical soil properties affected by short and long-term (14 years) continuous no-tillage and controlled traffic

•Soil mechanical and hydraulic properties were measured on soil with controlled traffic.•A framework with 4 phases (initial, intermediary, transitional, and near-stabilized) conditions was proposed.•Final stage of lowest entropy after 14 years of no-tillage is near steady-state, but still in “loosening” process.•Soil capacity and intensity properties should be measured to fully assess soil system behavior over time. Recent studies have shown harmful effects of soil compaction in no-tillage system (NTS), but there are indications that soil structure improves with time of NTS adoption. We formulated the hypothesis that topsoils of NTS initially have worse soil physical conditions than those under conventional systems, but these conditions gradually improve with time also down to deeper depth, even when the soil is wheeled by farm machinery. Our objective was to evaluate the effect of a long-term no-tillage system and machine traffic on soil mechanical and hydraulic properties. The treatments and soil conditions consisted of five periods since the last conventional tillage (or age of NTS) in a Hapludox: 0.2, 1.5, 3.5, 5 and 14 years, with and without traffic; named recent tillage, and initial, intermediate, transition and stabilized NTS phases. Soil samples were collected from soil layers 0–7, 7–14 and 14–21cm depth to determine soil porosity, precompression stress, compressibility coefficient, saturated hydraulic conductivity, air permeability, water retention curve, bulk density and organic carbon. Conventional tillage of soil previously under no-tillage significantly affected soil capacity properties, resulting in high macroporosity and deformation susceptibility, low bulk density and precompression stress. Intensity properties were affected initially by an increased soil pore obstruction, negatively affecting air permeability and saturated hydraulic conductivity, from 0 to 21cm soil depth. However, after five years of no-tillage there was an increase in microporosity and, although small, in soil organic carbon, especially in the 0–7cm soil layer; thus, soil water retention and soil intensity properties (like soil water and air permeability) were also improved, regardless of farm machinery traffic. Over time, soil reconsolidation occurred, which resulted in reduction of the compressibility coefficient and degree of compactness, mainly in the upper layers (0–7 and 7–14cm). However, in the deepest layer with the least disturbance, the degree-of-compactness a