Small Farm: What is a Healthy Soil?		AG1056
Carole Hollier, Rutherglen Updated: September 2006
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Agriculture relies on healthy soils to produce quality crops and pastures. But mention soil health and most people focus on soil fertility. There are many aspects that need to be considered when thinking about the “health” of a paddock.

Soil must be physically, nutritionally and biologically balanced be productive and stable. Soil structure decline, soil acidification and soil erosion are common soil health issues with the potential to severely restrict agricultural productivity on susceptible soil types, while erosion may also contribute to downstream sedimentation and turbidity within water storages.

Good soil health is about creating a robust soil that can withstand impacts, such as agriculture, without loss of fertility, structure and biological activity.

Victoria: the state of our soils

Many soil health problems occur as a result of natural processes, however agricultural practices can influence soil health.

• Clearing of native vegetation has changed the water balance in our soils and has removed vital groundcover.
• Severe soil acidity (pH Ca less than 4.5) has affected soils.
• Lack of surface vegetation had led to moderate to severe gully erosion.
• Dryland salinity affects agricultural soils.
• Severe soil structural decline (hardpans, surface crusting, sodicity and slaking) affects agricultural soils.

• Apply lime once pH drops below 5. Lime is the only way to reverse acidification! Lime will create a more favourable environment for soil biota.
• Retain and sow deep-rooted perennial grasses to reduce nitrate leaching.
• Apply maintenance dressings of lime as required, after the first remedial rate has been applied (approximately 150-200 kg lime/ha/year is needed to balance the acidification caused by agriculture).
• Match timing of fertiliser application with maximum demand by plants to reduce nitrate leaching.

• Slow or retard water flow to reduce erosion.
• Maintain groundcover through good grazing management and retaining stubble.
• Maintain and improve drainage line vegetation.
• Adopt land class fencing and whole farm planning practices to use land within its capability.
• Minimise soil disturbance.
• Repair active gullies early.

• Adopt good grazing practices: pay attention to stocking rates, remove livestock from wet areas, maintain vegetation cover.
• Adopt minimum tillage and direct drilling to improve soil physical conditions. Avoid cultivation if soil is too dry or too wet.
• Include a pasture phase to improve soil structure. This will improve physical soil features such as water infiltration and will increase organic matter to support greater numbers of earthworms and microbes.
• Retain stubble: to increase organic matter and improve water infiltration.

• Use appropriate cropping rotations for improved organic matter, disease breaks and more diverse nutrient sources for soil biota.
• Maintain soil fertility: soil test regularly and apply fertilisers according to crop and paddock needs.
• Retain stubble: improves soil organic matter (food source for soil organisms).
• Minimise cultivation: retains a food source for soil biota.
• Lime acidic soils: provides a more favourable pH for soil microbes and earthworms.
• Reduce compaction: limit traffic from machinery and over-stocking. Compaction reduces soil drainage, causing unfavourable soil conditions for biota.