The Wonderful World of Soil Biology
case studies have demonstrated that by supporting the biological activity in their soil, they can increase the nutrient availability, health and productivity of their soils. This process is becoming more widely understood, as new technologies provide access to much more detailed information about the biology of the soil and how to adjust it to improve productivity and profit (see the recent ABC Landline episode on Soil Secrets).
Our case study participants used techniques such as the application of organic composts, worm juice and biological amendments to enhance the biological activity and productivity of their soils. (It is important that appropriate amendments are tailored to individual soils.) They also used stock management practices to control grazing pressures and distribute nutrients, the direct-drilling of seed and reduction or cessation of chemical inputs.
From sand to soil...
By focusing on restoring the natural biology of their soils, farmers in WA and SA have been able to regenerate nutrient-poor sands back into productive and resilient soils.
In the WA Central Wheatbelt, Ian and Dianne Haggerty of the Prospect Pastoral Company coat seeds with beneficial micro-organisms before sowing and apply biological fertilisers, including high grade worm liquid and compost extract, at the cost of $30 a hectare. By limiting soil disturbance through direct-drilling or no-till cropping, they also limit disturbance to micro-organisms and fungi. As a result, they are producing consistent crops and premium fat lambs on very limited rainfall (as little as 100mm in the growing season!).
Soil under the Haggerty’s crop is clearly improved with organic matter after just two crops, compared with the spadeful of sand taken from the edge of the property.
Similarly, David Clayfield of Clover Estate in SA adopted a soil biology building program. This incorporated an annual application of compost extracts (at 50 litres a hectare), as well as bio-fertilisers to help address plant nutrient imbalances, cycling and availability limitations in his sandy soils. As a result he can now grow pastures to help rear calves for export as dairy heifers with a 33% production increase, using 25% less irrigation. And look at the changes he’s achieved in his soil!
After 15 years of organic treatments, David Clayfield's sandy soils are darker with higher organic matter content and biological activity, enhancing nutrient transfer and water-holding capacity.
The Soils for Life Team