Estimates of erosion on potato lands on krasnozems at Dorrigo, NSW, using the Cesium-137 technique

Abstract

A paddock typical of those used for potato cultivation with respect to soils, topography and management was sampled in a grid pattern to determine the redistribution in the soil of the environmental isotope, caesium-137. The total erosion in this paddock, which had been used to grow three spring crops of potatoes in rotation with kikuyu-based pasture, was estimated from the proportional change of caesium-137 content relative to the content in a local, stable reference site. Over the sampled area (3.2 ha), total erosion was estimated to average 297 t ha-1, equivalent to 98 t ha-1 per crop. Comparative erosion estimates were made from the results of single transect sampling in a paddock used for two potato crops and in one under permanent pasture. Results suggest erosion rates of 57 t ha-1 per crop in the former site and 0.09 t ha-1 year-1 in the latter site.