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

摘要: Recent studies have shown harmful effects of soil compaction in no-tillage system (NTS), but there are indications that structure improves with time NTS adoption. We formulated the hypothesis topsoils initially worse physical conditions than those under conventional systems, these gradually improve also down to deeper depth, even when is wheeled by farm machinery. Our objective was evaluate effect a long-term and machine traffic on mechanical hydraulic properties. The treatments consisted five periods since last tillage (or age NTS) Hapludox: 0.2,1.5, 3.5, 5 14 years, without traffic; named recent tillage, initial, intermediate, transition stabilized phases. Soil samples were collected from layers 0-7, 7-14 14-21 cm depth determine porosity, precompression stress, compressibility coefficient, saturated conductivity, air permeability, water retention curve, bulk density organic carbon. Conventional previously no significantly affected capacity properties, resulting high macroporosity deformation susceptibility, low stress. Intensity properties an increased pore obstruction, negatively affecting permeability 0 21 depth. However, after years increase microporosity and, although small, carbon, especially 0-7 layer; thus, intensity (like permeability) improved, regardless machinery traffic. Over time, reconsolidation occurred, which resulted reduction coefficient degree compactness, mainly upper (07 cm). deepest layer least disturbance, degree-of-compactness increased. evolution processes (from phase) for no-tilled proposed controlled uncontrolled systems as framework based field data process creating aggregates represented, at first, number contact points before they re-loosened strengthened same rearrangement particles, reducing aggregate increasing strength time. divided into 4 phases: initial (1.5 years), intermediary (3.5 transitional (5 (14 years) conditions. (C) 2015 Elsevier B.V. All rights reserved.