Nature and magnitude of soil erosion in sugarcane land on the wet tropical coast of north-eastern Queensland

Abstract

This paper reports measures of soil erosion in sloping sugarcane land under conventional cultivation and various no-tillage surface management techniques and explores the reasons for the differences measured. Soil erosion from conventionally cultivated ratoon cane lands was measured in the range 47-505 t/ha.year, with an average annual loss of 148 t/ha.year. No-tillage practices reduced this erosion to <15 t/ha.year. Groundcover did not affect soil erosion significantly. In the absence of hydrological data, it is anticipated that consolidation of the soil surface at harvest, rather than ground surface cover, is the dominant factor reducing soil erosion. The effect of groundcover on soil erosion is less than the accuracy of the measurement techniques employed (¦ 20 t/ha.year). Physical and chemical analyses of in situ and eroded soil indicate that sediment from the no-tillage practice may be transported further from the erosion site and carry a more mobile fraction of nutrients.