A/Prof. Greg Hancock1, Dr Veikko Kunkel1, Dr Tony Wells1, Dr Cristina Martinez2
1The University Of Newcastle, Callaghan, Australia, 2School of Agriculture and Food Sciences, The University of Queensland, , Australia
There is much to learn regarding its spatial and temporal distribution as well as how soil organic carbon moves through the landscape. Of particular interest is how soil organic carbon movement is related to soil erosion and deposition. This study examines the spatial distribution of soil organic carbon in a (562 km2) catchment in relation to soil erosion and deposition from 2006 to 2019. The results demonstrate that the spatial distribution of soil organic carbon concentration on average is stable. However, differences were found in soil organic carbon when concentrations were compared between samples collected at different time periods. The environmental tracer caesium-137 (137Cs) was used to assess erosion and deposition patterns. We found a significant relationship between soil organic carbon change and erosion and deposition at each sample point. That is, sample sites with an increase in soil organic carbon corresponded with an increase in 137Cs concentration (depositional sites) while locations with a decrease in soil organic carbon corresponded with a decrease in 137Cs concentration (erosional sites). The results were confirmed using a Monte-Carlo assessment. The reason for the soil organic carbon change and soil movement was the largest rainfall event (since 1969) in the area. The findings suggest that soil organic carbon can be translocated by significant rainfall events.