How fast do soils form?
Rates of soil formation in North Queensland are being studied on basalt lava flows which are dated by K/Ar. In the semi-arid Hughenden- Charters Towers region (500-600 mm/year rainfall), soils form at rates of ~0.3 mm/1000 years. On the Atherton Tableland, (rainfall 1200-3500 mm/year) rates are significantly faster, up to ~4 mm/1000 years. By any measure such rates are exceedingly slow and are a reminder that current rates of soil erosion associated with farming are not sustainable.