A simple laboratory infiltration method for measuring the tendency of soils to crust

Rainfall simulation experiments give an indication of the tendency of soils to crust or seal but are time-consuming and require several kilograms of soil per sample. We developed a laboratory infiltration method that is less time-consuming than rainfall simulation and uses less than 40g of soil. The method involves the leaching of an agitated 1:5 soil/water suspension through a packed soil column, which simulates the crusting process. The preparation of a dispersed soil suspension is a key feature of the method as it simulates disturbance of a soil surface by rain. This laboratory infiltration method was performed on sandy, granite-derived soils from annually burnt as well as unburnt plots in the Kruger National Park, South Africa and gave results which correlated strongly with results from rainfall simulation experiments on the same soils. We suggest that this new method may be useful for assessing the effect of different land management practices on the tendency of soils to crust.