Page "Tropic of Capricorn" Paragraph 8

As with the Tropic of Cancer, most places along the Tropic of Capricorn have arid or semi-arid climates, though with the Tropic of Capricorn this unfavourable environmental state is exacerbated by the fact that in Australia and Southern Africa tectonic activity and glaciation have been largely absent since the Carboniferous 300 million years ago, so that the aridity is compounded by extremely infertile soils.

This results in a generally scrubby vegetation, with perennial grasslands occurring in less infertile cracking clay soils.

In Australia, areas on the Tropic have the most variable rainfall anywhere in the world and thus even the wetter areas cannot be generally farmed since irrigation sources invariably dry up in drought years.

In southern Africa, where rainfall is more reliable, farming is possible though yields are low even with fertilisers.