PORE CHARACTERISTICS OF SOILS FROM TWO CULTIVATION EXPERIMENTS AS SHOWN BY GAS DIFFUSIVITIES AND PERMEABILITIES AND AIR‐FILLED POROSITIES

摘要: Summary Gas diffusivity and permeability, air-filled porosity, were measured in undisturbed soil cores at six water potentials between -2 kPa oven dryness. All increased as potential fell. In silt loam 30 to 80 mm depth, relative air permeability 0.0013 5 × 10−8cm2 after direct drilling, 6 15 times greater respectively ploughing, presumably because of the larger volume large pores ploughed soil. These may also have been more continuous or less tortuous than drilled However, equal porosities up 0.18 v/v, apparently any given matric potential, gas within below previously layer isotropic. clay depth irrespective tillage but on drying.