Managing Soil Erosion Risk

Giles Forward (DEWNR) speaks to us about their monitoring program to assess and manage soil erosion risk in South Australia.

The Department of the Environment, Water and Natural Resources is monitoring the risk of erosion levels across South Australia. Senior project officer Giles Forward tells us more about the project.

Field Erosion Surveys in South Australia

We commission of a monitoring program where we do drive-by field surveys in the agricultural cropping districts of South Australia. We’ve selected particular road transects across the main agricultural cropping regions and we go along those roads looking at the same paddock sites four times each year.

It’s about 5500 sites that we’ve used and we do a set of paddock observations of the amount of ground cover and whether there’s soil being disturbed or not and what sort of cropping phase or pasture phase the paddock is in at that time. We score the cover rating from a scale from one to eight whether it’s for a full standing cover through to completely bare soil, we do a rating for how disturbed the soil is: whether it’s completely firm, or whether it’s been tickled up a little bit or whether it’s been cultivated, we really put that information together with also with the soil type and landscape type overall estimate of the erosion risk.

Monitoring Risk Target Levels for Soil Erosion

From our field erosion protection surveys, we were able to estimate the overall erosion risk for the amount of land protected at different times of the year and so from year to year we can really monitor that one of the key targets that we gather this data for is the south Australian strategic plan target T70.

Its called sustainable land management. that aims to achieve a twenty percent improvement in the protection of a agricultural cropping land from erosion from the baseline year of 2003, through to the target year of 2020. We’ve been doing these surveys since year 1999 nearly twelve years of data.

And we certainly can see an improving trend in soil erosion protection. We’ve seen that despite recent drought years that so erosion protection has continued to improve. So its really the credit to improved farming practices.There’s been a large increase in the use of no till &  zero till practices over that 10 to 12 year period and we think that’s gone a long way to explaining the improvement in soil erosion protection that we’ve got from our field survey.

The Benefits of Reducing Erosion

The benefits, I guess, primarily are that the valuable topsoil is being retained in the paddock, so that the fertility of the soil can be maintained and improved. If soil erosion does occur it can cause damage, emerging crops any practices that can Minimize the amount of time that the soil might be exposed through a cultivation or burning will certainly help to reduce that erosion risk.

And likewise, managing grazing to maintain adequate cover on the ground can also help quite a lot. Standing stubble will give better protection from wind erosion, then there’s stubble that’s been flattened down to the ground. On sloping land that might be prone to water erosion, it’s a bit different in that we want to protect the ground from the impact of rain drops so it’s actually it’s more important to have an even cover across the ground to cover over as much ground as possible.

The cropping lands are well on their way to reaching the target, but there’s a way to go yet we’re still hoping there can be further improvement in soil erosion protection over the coming years.