Soil physical characteristics
The dominant soil of a land resource inventory area is mapped according to the following key soil physical characteristics: topsoil gravel content, rock outcrops and surface boulders, and particle size.
Topsoil Gravel Content
The gravel content (%) of the top 20 cm of the soil profile (0–20cm). The amount of stones affects a number of hydraulic characteristics of the soil as well as its workability and root penetration characteristics. The classes are as described in Webb and Wilson (1995).
Rock outcrops and surface boulders
The coverage of rock outcrop and surface boulders (%). Rock outcrop and surface boulders act as a hindrance to machinery and constrain management practices. The classes are as defined in Webb and Wilson (1995).
Particle-size class describes the proportions of sand, silt, and clay in the fine earth fraction of the soil except, in the case of skeletal soils ( >35% coarse fraction) where it applies to the whole soil. Particle size is important for soil trafficability, soil workability, and moisture storage capacity and permeability. The classes are as described in Webb and Wilson (1995).