Figure 2.

Temporal and spatial distribution of 4 main aluminum (Al) forms in soils around bayberry tree roots. The concentrations of aluminum (abscissa axis) in different soil depth (axis of ordinates) from sample soil of the different tree ages of T10 for 10 years old, T20 for 20 years old, and T30 for 30 years old were showed for exchangeable Al in (a), for colloidal Al in (b), for hydroxyl Al in (c), and for humic-acid Al in (d). The different letters represent significant differences in different tree age bayberry (p < 0.05).