Soil Permeability - Page 9
Page 9 of 9
Best practice principles for the management and monitoring of soil drainage and waterlogging
Dryland crops and pastures
- Retain stubble
- Soil colour provides an overview of aeration and drainage status of soil.
- Loosen compacted zones and improve soil structure (increase soil OM, application of gypsum on sodic soils).
- Adopt zero tillage and controlled traffic
- Implement soil management strategies such as ‘raised beds’ for cropping, where appropriate.
- Monitor water tables to assess whether management change is depleting or restoring the natural water resource, and as a trigger for action.
- Applying foliar N fertilizer when crops resume active growth can reduce N deficiency induced by waterlogging.
Note: Application of foliar N on already waterlogged crops may not reduce existing damage; high rates of N can burn foliage. - Harvest water (banks and dams) and encourage water use higher in the landscape
- Direct water away from waterlogged areas and safely into grade banks and drainage channels
- Plant belts of perennial plants to use the water more effectively. Address position in the landscape (may be more pertinent to increase water use on upper slopes to reduce in-flow)
- Minimise fallow periods and maximise the frequency of plant cover
- Waterlogging and surface flooding can occur from water generated from neighbouring properties. Neighbours should work together to solve the problem.
Irrigated crops and pastures
- For tree crops, where water tables occur within 1 m (sandy soils) or 2 m (clay loams) of the soil surface, waterlogging stress is likely to be severe. Salt from the water table has readily moved into the root zone due to evaporation at the soil surface.
- Monitor the level of the water table. Water tables rise and fall from winter to summer and after irrigations, and can indicate over- or under-watering. If water tables rise into the root zone, waterlogging and root rot will occur.
- Schedule irrigation to maintain or improve crop yield, manage salinity problems, assist with drainage and irrigation management and to make more efficient use of fertilisers, and the water resource.
These options will give plants a greater ability to use dissolved nutrients and will contribute to reducing nutrient loss. Importantly, the same management mechanisms can also reduce groundwater recharge and assist other measures in managing areas prone to salinity. Note: Where improved soil drainage results in more deep drainage to groundwater, salinity problems may be exacerbated.