The chemistry of the pedoderm - part 3: Colophospermum mopane shrublands and woodlands in the central Kruger National Park, South Africa

The woody plant, Colophospermum mopane, occurs as either a shrub or tree in shrublands and woodlands, respectively, in the central Kruger National Park, South Africa. As a first step in identifying which soil properties potentially influence the structure of C. mopane in these landscapes, we investigated the soil chemistry of the pedoderm in shrublands and woodlands. A total of 39 composite pedoderm samples (0-2 cm) were analysed. Relative to the woodlands, the pedoderm of the shrublands had significantly lower mean concentrations of P, K, Ca, Mg, S, Mn, Cu, Na, B and C. Of the nutrients analysed, only B had a mean concentration likely to be constraining the growth of plants (0.16 +/- 0.01 vs 0.69 +/- 0.05 mg B kg(-1) in shrublands and woodlands, respectively). We suggest that the C. mopane shrubs do not establish as trees in the shrublands because deficiency of B limits their growth and increases the competitive strength of the grass sward relative to eudicot plants in the landscape.