5.1.15 (HL)—Soil classification

Classify a soil profile by horizon depth, colour, organic matter and translocation evidence, not one visual cue.

Brown-earth-type profiles commonly show organic-rich surface and active cycling; oxisol-type profiles are deeply weathered, iron-rich and nutrient-poor. Treat these as evidence patterns, not labels without data.

A deep red, strongly weathered profile with low nutrient retention supports an oxisol interpretation more than a dark, moderately leached profile.

Iron, moisture and organic matter can all alter colour; combine depth, texture and chemistry.

A profile type is an inference from processes, not a name assigned from one horizon.