Effect of fallowing practices on runoff and soil erosion in south-eastern Australia

Abstract

The effect on runoff and soil loss of four methods of preparation of fallow was investigated at each of three sites in north-central Victoria. There was a chemical fallow treatment (uncultivated) and three scarified treatments (smooth, medium and rough cultivation). When the results from the three sites were combined, there was 10.7 mm runoff from the uncultivated treatment, 5.1 mm from the smooth, 0.8 mm from the medium and 0.3 mm from the rough scarified treatments. Soil loss from the uncultivated treatment was 103 g/m2 compared with 87 g/m2 from the smooth, 22 g/m2 from the medium and 13 g/m2 from the rough treatment. The concentration of sediment in the runoff was negatively correlated (R2 = -0.56 to -0.98) with runoff. It ranged from 1.21% (w/w) for the uncultivated to 5.06% (w/w) for the rough scarified treatment. The results show that a regimen of minimum scarification to produce a rough surface, and then use of herbicides to control weeds, reduces soil loss compared with either an uncultivated or a smoothly cultivated soil surface.