Soil
- Erosion Management
- Acid sulfate soils and potential acid sulfate soils
- Saline & sodic soils
Erosion Management
Conserve and maintain the structure, fertility and biological characteristics of your soil using one or a combination of the following techniques.
Where practicable, use minimum tillage planting systems to reduce the potential for soil erosion. For example:
- adopt spray-out fallow or retain fallow land under a cover crop;
- avoid cultivating land to a fine tilth; and
- minimise the number of cultivations in preparation of the plant crop and the maintenance of ratoon crops.
Where there is potential for erosion, adopt a modified contour system in which rows areplanted approximately on the contour, coupled with the use of contour banks and water ways.
Practise early fill-in of plant cane to allow soil to consolidate and reduce erosion.
To minimise erosion and improve soil health, adopt green cane harvesting and trash blanketing in those areas where this method is compatible with profitable cane growing.
Acid sulfate soils and potential acid sulfate soils
Acid sulfate soils and potential acid sulfate soils do not occur in all cane growing areas but where they do, special management is necessary.
If you cultivate soils with a potential acid sulfate soil layer between 0.4 m and one metre of the surface, you can minimise the potentially negative impact on adjacent areas by ensuring that:
- the depth of potential acid sulfate soil layers is determined;
- cultivation does not penetrate the potential acid sulfate soil layer or bring it to the surface;
- drains do not penetrate the potential acidsulfate soil layer unless the water table is maintained;
- natural water tables are not artificially lowered into the acid sulfate soil layer as this may result in the oxidisation of the potential acid sulfate soil layer;
- water storages should be designed appropriately;
- where potential acid sulfate soil layers are disturbed, bury them below the water table level.
If any of the potential acid sulfate soil layer is disturbed and oxidation of the potential acid sulfate soil occurs, you should try to minimise the negative impacts on adjacent systems.
Appropriate action may include:
- installing drainage schemes which do not further disturb the acid sulfate soil layer;
- increasing pH of leachate within 48 hours of disturbance by liming of drain edges and drain spoil;
- liming of soils to increase pH; and
- visual and pH monitoring of run-off from the drainage system after installation.
Controlled tidal flood gate management may be appropriate in established cane growing areas which contain potential acid sulfate soils.
The distribution of potential acid sulfate soils in Queensland is currently being determined by the DNR. Contact your local DNR office to determine whether maps are available for your area.
Saline & sodic soils
The following techniques may prevent the development of saline and sodic soils or aid in their management:
- ensure that drainage schemes in potentially saline areas are coordinated across the catchment to minimise the effect of discharge of saline water;
- soil ameliorants such as gypsum should be applied;
- where practicable, retain harvesting residue to reduce soil sodicity;
- maintain an adequate topsoil layer to prevent subsoils (B-horizon soils) being exposed as a result of levelling or clearing;
- where subsoils are exposed during levelling, a topsoil layer should be returned;
- adopt good irrigation management practices to prevent rising water tables.
