• At Glenalpine and the Strathalbyn black soil paddocks , there did not appear to have been any new erosion initiated as a result of the trials . Rather , erosion occurred as a continuation of existing gullies . The types of gullies in these paddocks ( dominantly linear gullies ) were relevant to this finding and suggested those gully types , particularly gullies < 1m deep , are more amenable to the trialled grazing management practices .
• At the Strathalbyn alluvial site , the trial has demonstrated reductions in erosion have been achieved , with up to 98 per cent effectiveness ratios in some years . The stomping treatment was undertaken in conjunction with earthworks , capping and seeding . While efforts have been made to limit the influence of major earthworks on the trial outcomes , the effectiveness of the trials is likely a combination of these factors .
• Persistent erosion processes in the Dunn ’ s Paddock remediation site suggests challenges are likely to be faced for alluvial gully remediation using only techniques and materials commonly available to landholders .
• Lidar change detection analyses were considerably impacted by survey data acquisition schedules when ground vegetation cover was high . As such , ALS surveys were affected by high levels of noise from vegetation signal , persistent in the data . This outcome limits the ability of the data to effectively identify erosion or depositional zones .
• The limit of detection used in ALS change detection analyses has a substantial influence on the quantities of detectable erosion and deposition and should be carefully considered in the interpretation of results from multiple survey analyses .
• Even at high resolutions , ALS data does not have the ability to detect fine-scale erosion processes , such as hillslope erosion or gradual wash erosion ( e . g . where processes are anticipated to be << 5 cm per year ). There is limited effectiveness in monitoring processes below this threshold , particularly across broad landscape areas .
• ALS survey data is most beneficial on bare ground surfaces or where vegetation cover is low so that a true ground signal can be detected . As a monitoring tool , it is likely to be most effective at detecting gully head retreat , sidewall erosion and channel erosion .
The May 2022 consensus field visits , facilitated by Dr . Christian Roth , observed project sites at Glenalpine , Tabletop , Hellsgate and Desmond , and Strathalbyn .
‘ Overall , there was a greater acceptance of experiential or qualitative
evidence by scientists than at the start of the Stomping out Sediment project . Conversely , graziers were more comfortable being challenged in their understanding of underlying processes and supportive of further monitoring or even follow-up research . There was consensus that experiential and qualitative data was legitimate , but that ideally it is backed up by quantitative measurements , recognising that in some instances appropriate methods are still lackinWg ( e . g . to measure soil health ) or too resource intensive ( measuring runoff and sediment discharge ).
’
— Dr Christian Roth
Some of the key conclusions from the site visits included :
• The main grazing management principles to emerge from the discussions and the actual practices being implemented across project sites converged on the following :
o Increasing the distribution of watering points , in conjunction with fencing out smaller paddocks around each watering point .
10 o Planned rotation of cattle mobs . Size of mobs and duration of graze in each paddock