THE SOIL BELOW A TERMITE MOUND

Summay Concentric cones of whitened soil extend approximately 20 ft. below a termite mound in Southern Rhodesia. The pale colour is due to finely divided carbonates; the outer cone contains about 4 per cent. carbonates whilst the inner cone, riddled with termite galleries, has about 2 per cent. carbonates. The pH pattern shows highest values in the inner cone due to the presence of sodium salts. Termite activity thus gives rise to calcareous and sodium‐influenced soils in an area of leached ferrallitic soils. Physically, the soil below the mound has the same arrangement of horizons as the surrounding ferrallitic soils, namely, mineral material (M horizon), over a stone horizon (S horizon), over weathering granite (W horizon). The overlap of the inner cone and horizon W indicates that this arrangement of horizons has been brought about in part by termites carrying material up from the W horizon through the S horizon to the M horizon or mound at the surface. Termite activity has thus influenced both the pattern of salt distribution and mineral‐soil horizons.