Biological farming is all about farming with respect to natural processes…looking after your soils, not only the soil chemistry but also the biology and soil physical structure. Soil carbon, as organic matter, is the secret weapon of biological and organic farming.
Healthy soils function to:
- maximise sustainable plant growth and plant health
- sustain biological activity
- store and cycle water and nutrients
- decompose organic matter
- bind toxic compounds
- suppress pathogens
- protect water quality and enhance catchment health
Soil carbon significantly enhances all characteristics of healthy soils; soils with low organic matter content cannot achieve the above functions.
Soils are very complex chemical and biological systems. The soluble and exchangeable nutrients typically make up less than 1% of soil mass. Soils have a large store of bound nutrients often regarded as the ‘Totals’ – historically these nutrients were ignored. We now know soil processes and biology can access this potentially vast nutrient source (see the diagram below).
Rock phosphate fertiliser was historically avoided, as the nutrients were considered inaccessible to plants… but now it’s having widespread success in biological and carbon based farming systems. After all, what is superphosphate? Its rock phosphate boiled in sulfuric acid to artificially solubilise nutrients! However, altering these natural processes can affect soil health, impacting on soil biology, leachate loss and binding of soluble phosphorus.
Soil Management with Compost
Compost can be used to sustainably manage soils. The organisms inherent in compost build soil structure, decrease water use and re-establish natural disease controls. The soil foodweb cycles nutrients into plant available forms and bind leachable nutrients into an accessible weak organic matrix.
Additions of good quality compost can increase:
- soil organic carbon
- cation exchange capacity
- soil buffering capacity – an inherent liming value
- release and cycling of nutrients
- water holding capacity
- soil biology
- better crop yields
- binding of agro-chemicals
- carbon sequestration, reducing greenhouse emissions
- carbon offsets for trading
So what can you do…? While it’s not easy, it’s worth it!
- Use Soil Health Cards. They’re freely available on the internet.
- Use soil analysis as a tool to reduce and target fertiliser applications.
- Use pesticides, fungicides, or both, only after careful consideration.
- Return organic matter to the soil, then manage this most valuable asset.
- Understand soils need the biota, bacteria and fungi
Article kindly provided by the Southern Cross University Environmental Analysis Laboratory.