Time-controlled grazing and soil erosion control under a catchment scale experiment in South-east Queensland, Australia

摘要

Grazing systems affect pasture production and hence surface cover which is the protective layer of soil against water erosion. Time-controlled (TC) grazing as an alternative to conventional grazing systems has become popular in some parts of Australiaand rest of the world for its relatively higher pasture productivity. It involves short periods of intensive grazing which is of concern for environmental impacts and sustainability. To address some aspects of the issue, a runoff catchment experiment was established to investigate the effect of the newly adopted grazing system (TC grazing) on runoff and sediment loss from 2001 to 2006. The results show that sediment loss was reduced significantly over the study period as the surface cover increased. The reduction in soil erosion was achieved despite the fact that the increase in ground cover under TC grazing had little effect on runoff. Decrease in runoff and soil loss is mostly . attributed to the higher level of surface cover (90%) achieved during the second period of the study (2004-2006) compared with 65% for the first (2001-2003). Long rest periods in TC grazing was seen to be the major contributor to soil and pasture recovery after the intensive defoliations and subsequent increase in above ground organic material providing soil erosion control.