5.1.7—Soil transformations

A transformation changes form or chemical identity; decomposition, weathering, nutrient cycling and salinization are not simple movement.

Decomposition changes organic matter into smaller compounds; weathering changes parent material; microbes transform nutrient forms; and evaporation after irrigation can concentrate dissolved salts until solid salts accumulate, producing salinization.

Dead leaves become mineral nutrients through decomposition; the nitrogen is chemically transformed before plants absorb it.

Nitrate moving downward unchanged is a transfer; a transformation changes its chemical or physical form.

A process can include both movement and transformation; identify which step the question asks about.