Is chiseling or inverting tillage required to improve mechanical and hydraulic properties of sandy clay loam soil under long-term no-tillage?

- Soil compression, shearing, and hydraulic properties were studied.
- Soil properties analyzed pertain to two groups: functional and composition.
- Inverting and chisel tillage have little or short-lasting effects on soil structure.
- Reconsolidation over short-time profoundly affects soil structural condition.
- Soil tillage is not need to improve soil structure of sandier subtropical soil.

Dynamic soil properties as affected by machine-soil interaction are potential indicators for the evaluation of management and traffic effects on soil structure. Our objective was to determine compressive, shear, and hydraulic soil properties in a sandy clay loam Hapludalf, under continuous no-tillage and tillage operations to ameliorate soil physical conditions. The studied tillage systems were long-term (13 years) continuous no-tillage (NTc); chisel tillage two years before the experiment (CH2); inverting tillage performed on NT soil, 2 years before and just-before the experiment (IT2,0); and chisel tillage performed on NT soil 3 years before and just-before the experiment (CH3,0). Soil precompression stress, compressibility coefficient, cohesion, angle of internal friction, aggregate resistance, bulk density, porosity (total, macroporosity, microporosity), and water retention (field capacity, permanent wilting point, available water, and drainable water) were determined for 0.01-0.03 m (surface) and 0.10-0.12 m (subsurface) soil layers. The results show inverting and chisel tillage of soil previously under long-term no-tillage has little and/or short-lasting effect on soil composition and functional physical properties. Soil reconsolidation over time significantly affects soil structural condition. Thus, soil tillage is not need to improve soil structure of sandy clay loam subtropical soil. Furthermore, the terms capacity and intensity properties should not be used as synonyms to composition and functional properties, but they should rather be reserved to the thermodynamically basic quantity-intensity-capacity concept.