Differences in soil organic carbon and soil erosion for native pasture and minimum till agricultural management systems

Suspended sediment load estimation in an ungauged river in south‐eastern Australia

“…On average, it is estimated that 0.029 t/ha/year of sediment is generated across the whole catchment from the hillslope using SedNet. This is generally consistent with the soil erosion rates found in studies in Krui subcatchments and similar large catchment scale studies (Armstrong & Mackenzie, ; Hancock et al, ; Martinez et al, ; Wells et al, ) but is lower than figures published in the NLWRA for national and NSW sites (Lu et al, ; NLWRA, ; Wilkinson et al, ). Similarly, bank and gully erosion rates (0.02–0.001 t/ha/year) are orders of magnitude lower than rates found by the NLWRA () for NSW.…”

“…Similarly, the agreement between the estimated suspended sediment concentrations and observed data indicates that the two datasets have performed well in the model. Information from landholders indicates that land use has been consistent across the catchment since 1975 (Wells et al, ), and so the data used here are believed to be representative of current catchment conditions. As a result, historical (over a sufficient temporal range and during representative conditions) and modelled data can be used to overcome the issue of poor flow data availability.…”

“…Denudation rates were found to range from 0.02 to 0.07 mm/year for the Stanley subcatchment by Hancock et al () and Martinez et al (). Wells et al () estimated denudation rates at the paddock scale of 4 and 0.6 mm/year for a cropped and grazing site, respectively. These rates were found to be stable from 2005 to 2015 (Wells et al, ).…”

“…These land uses and the area occupied by each have been relatively consistent over the past 40 years (Hancock et al, ). Erosion rates have been found to be stable over the past 15 years, allowing for comparison between field data and the modelled results (Hancock et al, ; Martinez et al, ; Wells et al, ). Finally, there are also no surface or groundwater extractions from the river system, simplifying any analyses.…”

“…Here, the SedNet model is applied to a 585‐km 2 catchment in the Upper Hunter of NSW, Australia, to link hillslope erosion rates to long‐term sediment export. It forms part of ongoing research into erosion rates, their controls, spatial variation, and the impact of agriculture on soil sustainability across a large catchment in eastern Australia (Hancock et al, ; Martinez et al, ; Wells et al, ). The East Coast of Australia is identified as a separate climate zone to the rest of Australia (Timbal, ).…”