Runoff (overland flow and A/B horizon interflow) was measured from 2 grazed
dairy pastures at Flaxley, South Australia, from 1996 to 1998. Runoff rang
ed from 0.4% to 10% of annual rainfall and >90% of this was overland flow.
Phosphorus and carbon were measured in runoff. As much as 2.3 kg/ha of phos
phorus and 10.7 kg/ha of total dissolved carbon were lost from the subcatch
ments in the wettest year. Over the study period, 98% of total phosphorus a
nd 86% of total dissolved carbon were lost in overland flow. Around 45% of
phosphorus was dissolved and 69% of total dissolved carbon was dissolved or
ganic carbon. The proportion of phosphorus present in the particulate form
decreased during each runoff season, and was highest in the wettest year. T
here was no consistent trend in the proportion of total dissolved carbon pr
esent as dissolved organic carbon because the factors found to affect disso
lved organic carbon loss were different from those affecting dissolved inor
ganic carbon loss. Predictive relationships based on factors such as the ti
me of year when the storm occurred and runoff volume have been developed fr
om the 3 years of data and they explain a high proportion of variability of
phosphorus and carbon loads.