We talk about the importance of having healthy soil. But what do we actually mean? What is healthy soil? Healthy soil is essentially soil with a functioning ecosystem.
Typically we use indicators like organic matter, nutrient levels, pH, cation exchange capacity, the depth and colour of our topsoil, water infiltration, and the presence of soil aggregates and earthworms to assess the health of our soil. Or the ability of our soil to provide outcomes like “sustain the productivity, diversity, and environmental services of terrestrial ecosystems”[1] and, for farms and gardens, to grow strong, pest and disease-resistant plants and nutrient-dense food, even when weather conditions are not ideal.
But functioning soil ecosystems are needed to improve these measures and achieve these goals![2]
Soil Ecosystem (in red circle)
The issues we experience with our soil, like low levels of organic matter, soil carbon, poor drainage, and nutrient deficiencies in food, tell us that our soil ecosystems are not in good working order. That’s why it doesn’t make much sense to spend our time, energy, and money improving these symptoms when we can improve the system itself!
Soil Organisms create Healthy Soil
By giving our soil organisms a decent diet they have the resources to:
- Maintain soil structures supporting soil life and root growth
- Break down organic waste materials into organic matter
- Produce acids and enzymes that release nutrients locked up in the sand, silt and clay particles in the soil [4]
- Recycle the nutrients from the organic materials and mineral particles and make them available for our plants to reuse
- Control soil pathogens and soil-derived plant pests and diseases through complex predator-prey relationships [5] [6]
- Naturally form beneficial symbiotic associations with plant roots [5]
Get the practical help you need with our Handbooks on building healthy soil for Gardeners and Farmers
References – What is Healthy Soil?
[1] FAO, 2020, Towards a Definition of Soil Health, The Intergovernmental Technical Panel on Soils, ITPS Soil Letters # 1, September 2020 (https://www.fao.org/3/cb1110en/cb1110en.pdf)
[2]Lehmann, J., Bossio, D.A., Kögel-Knabner, I. et al. The concept and future prospects of soil health. Nat Rev Earth Environ 1, 544–553 (2020). https://doi.org/10.1038/s43017-020-0080-8
[3] Wendy Seabrook, How to Build Health Soil, Learning from Nature (https://www.learningfromnature.com.au/how-to-build-healthy-soil/)
[4] Elaine Ingham, 2016, Roots of your Profit, Oxford Real Farming Conference 2016
[5]Thakur M.P., Geisen S., 2019, Trophic regulations of the soil microbiome. Trends Microbiol. 27:771–780. DOI: 10.1016/j.tim.2019.04.008
[6] FAO 2008. An international technical workshop Investing in sustainable crop intensification. The case for improving soil health. Integrated Crop Management Vol.6-2008. FAO, Rome: 22-24 July 2008
[7] Wendy Seabrook, Growing Nutritious Food Requires Functioning Soil Ecosystems, Learning from Nature (https://www.learningfromnature.com.au/how-to-build-healthy-soil/)
Diagram of soil ecosystems © Learning from Nature and soil organism – © Andy Murray
