Land degradation such as wind and water erosion, salinity and acidification can significantly reduce a farm's productive potential and impact the health of neighbouring rivers, wetlands and native vegetation.
Loss of surface soil from erosion has a major impact on productivity through the depletion of soil organic matter and associated soil nutrients. It destroys the surface structure of the soil resulting in surface sealing and compaction.
The Land Health program work with farmers to remediate land affected by:
- wind and water erosion
- dryland salinity
- land slips.
We provide management advice on land degradations issues such as erosion, salinity and acidification. Information is delivered through:
- farm visits
- field days
- soil health workshops
- grazing and sustainable cropping courses
- farm planning sessions.
- maintaining ground cover levels to maximise productivity whilst minimising soil loss and degradation
- erosion management plans
- monitoring and addressing dryland salinity
- matching land use and land capability
- being better prepared for climate change and the associated natural disasters
- undertaking works to control the remaining gully, rill and tunnel erosion
- coordinate strategies for managing landslips in high rainfall areas of the state.
Title: Topsoil loss — Protecting your farm's most valuable asset
Vision: Glenn Sturmfels , Agriculture Victoria kneeling in a grassy field
'Across Victoria, we are losing significant quantities of topsoil due to sheet, rill and wind erosion. Topsoil is the dark surface layer of the soil and is usually 10 to 20 centimetres in depth.'
Vision: Glenn is digging a hole in the field
'Topsoil is essential for growing crops and pastures, for feed grazing animals and as a source of food for the world's growing population.'
Vision: Close-up of dug hole
'It is priceless and irreplaceable.'
Vision: Sparse windswept field
'Over much of the state we are losing topsoil at an unsustainable rate, 5 to 10 times higher than it is being replaced by natural processes.'
'In a paddock like this the rate of soil loss could be 50 times higher than it's natural replacement rate.'
Vision: Heavy rain falling on ground
'On a yearly basis this would equate to about 13 hectare of lost topsoil, about 130 kg per hectare of lost organic matter and around 15 kg of lost nitrogen, phosphorus and potassium.'
Vision: Sheep moving across a field and barren ground leading to a large dam
'While difficult to quantify in economic terms, this landholder could easily be losing $100/ha/year in fertiliser alone without putting a value on the soil itself, organic matter and offsite impacts.'
Vision: Barren ground and different fields with barren ground
'In some of our more productive horticultural areas we are losing topsoil at an even higher rate due to slope, high rainfall intensity and excessive cultivation.'
Vision: Grassy field and a field of crops
'Topsoil is by far the most precious fraction of our landscape. We rely on topsoil to recycle organic matter, provide a habitat for biological activity and provide all the essential nutrients required for plant growth.'
Vision: Worms in soil
'Topsoil absorbs and stores large volumes of air and water.'
Vision: Pastures with sheep
'It is the powerhouse of our agricultural industry.'
Vision: Barren ground
'Over time erosion leads to surface sealing and compaction which significantly reduce plant establishment and growth.'
Vision: Glenn kneeling in soil eroded field
'What is causing this massive loss of topsoil?'
Vision: Foggy field, exposed land, overgrazed dry crops, bush fire ravaged landscape
'Topsoil loss is brought about by exposing our soils to wind and rain — the result of overgrazing, tillage or natural causes such as bushfire.'
Vision: Man in yellow raincoat with dog in rainy field
Vision: Water runoff in field from rain
'A lack of cover exposes our soil to the enormous energy of raindrops and wind. This results in massive damage to the soil structure and increasing volumes of surface runoff.'
Vision: Grassy hill and sheets of water running down a field
'The problem is magnified on sloping land as soil is swept downslope in a sheet of muddy water.'
Vision: Glenn on haunches demonstrating small gullies of water
'As this flow gathers speed it changes from sheet to channel flow and forms small gullies or rills across the paddock.'
Vision: Different landscapes showing result of wind erosion
'Wind erosion occurs when the speed of the air moving across the soil surface exceeds the ability of the soil particles to stay in place.'
'The very fine fraction of the soil containing most of the soil nutrients becomes suspended in the air and can travel for hundreds or thousands of kilometres.'
'Erosion mostly occurs during summer and early Autumn when our soils are dry, ground cover is low and summer thunderstorms are a common occurrence.'
'Often this erosion is barely noticeable to the eye, however it still has a significant impact.'
'What can we do to prevent sheet and rill erosion?'
Vision: Grassy fields
'In most cases the problem of sheet and rill erosion can be avoided by simply maintaining good ground cover at all times of the year, particularly during summer and late autumn.'
'100% ground cover will give you total protection although this is not always achievable.'
'However on steeper country or any landscape prone to soil erosion, pasture cover should be maintained as close as possible to 100%.'
Vision: Cropped fields
'Cropping should be restricted to slopes less than 5% and use techniques which minimise excessive cultivation.'
'Crop or crop stubble should be maintained to provide at least 50% ground cover and have at least one third of the stubble anchored firmly to the ground.'
'How can you assess ground cover accurately?'
Vision: Glenn demonstrating
'Make a square frame measuring 30 × 30 centimetres out of steel rod, stiff wire or timber.'
'Walk diagonally across a typical section of your paddock tossing the frame in a random fashion onto the ground.'
'Then use benchmark photographs to assess the percentage ground cover within your square frame.'
'Repeat the process 10 times or more and average the results.'