THE IMPACT OF EROSION ON THE PRODUCTIVITY OF A FERRALSOL AND A CAMBISOL IN SANTA-CATARINA, SOUTHERN BRAZIL

The impact of soil erosion on soil productivity was estimated for a Rh odic Ferralsol and a Eutric Cambisol in Santa Catarina, southern Brazi l. Over equivalent periods, total soil losses were an order of magnitu de different (868 and 68 t/ha respectively on the bare soil control), yet the impact on maize yield per tonne of soil lost was far greater a t the Cambisol site with less erosion. Similar interesting contrasts b etween sites were found for the other measures of impact with decline in pH and phosphorus and increase in free aluminium being the most obv ious induced soil differences. The results demonstrate the variable na ture of erosion impact according to soil type and they highlight the i mportance of examining a number of measures of impact before pronounci ng on the sustainability of any particular agricultural practice.