Soil Health is our Wealth

Our soils are precious resources and underpin sustainable food production and many other important ecosystem services for society. Our soild support the production of food, feed and fibre. There are many other functions supported by soil including, the re-cycling of nutrients, sequestration of carbon & regulation of our climate, purification and storage of water. Soils are also an important habitat for biodiversity. Researchers David Wall and Giulia Bondi have more information on soil.

Soil – a precious resource

In Ireland our grass-based animal production and high yielding arable cropping systems rely heavily on the availability of healthy soils to deliver high quality, profitable and sustainable food production on farms. The traditional view of high quality soil, measured by the soils performance for crop production alone, is now considered inadequate, as it does not consider the wider impact that soils have in the environment and for society.

From a food supply point of view, the health status of the soil also extends to food safety, human and animal nutrition and health. In addition to food, feed and fibre production, our soils support many other essential soil related services including, the re-cycling of nutrients, sequestration of carbon & regulation of our climate, purification and storage of water and soil are an important habitat for biodiversity. The sustainable management of agricultural soils as stated as being critical for achieving the targets set out in the Irish Governments FoodWise 2025 strategy for agriculture and more recently in the EU Farm to Fork and Biodiversity strategies and protecting soil resources is a specific objective of the post-2020 EU-Common Agriculture Policy (CAP).

How do we define soil health

Soil quality has been described as the soil’s ability to provide a range of different services through its capacity to perform the functions mentioned above under changing management and climatic conditions. Recently this term has been replaced by ‘soil health’, which emphasises the soil biological community as a key driver of soils capacity to deliver multiple functions. Soil health has been defined as the continued capacity of soil to function as a vital living ecosystem that sustains plants, animals and humans. In light of this, developing knowledge and understanding of factors affecting soil health and monitoring the trends in soil health over time is required to better manage and protect our agricultural soils for future generations.

What indicators can we used to assess the health of our soils

Holistically the health of our soil depends on the interaction and status of the three fundamental charactistics of soils; soil physics soil chemistry and soil biology. Researchers at Teagasc Johnstown Castle recently completed the first national inventory of soil health across Ireland using a set of standard indicators in the SQUARE project. Of the range of physical indicators measured soil structure can be considered a key factor that supports all other soil functions. The decline in soil structural quality which leads to soil degradation and compaction is often the consequence of more intensive management practices. This can also lead to reduced capacity for water to infiltrate and drain through the soil, to store water and to purify water in the landscape.

Chemical indicators in soils provide much information in relation to nutrient cycling, primary production and carbon sequestration functions in soils. In particular soil pH and soil organic matter were identified as a key factors, which regulate nutrient availability in soils and the delivery of different soil functions including carbon sequestration and macro/micro nutrient cycling. Soil biology have been described as the “engine of the soil” and that soil biodiversity and the soil microbiome is at the centre of soil functioning. Biological indicators provide valuable information on the effects of past and current management on soil health. For example, the abundance and presence of earthworms is a useful and easily identifiable soil health indicator. However, much of the soil biology cannot be seen with the naked eye and requires more sophisticated analysis, which may not always be practical for routine in-field soil health assessments.  

What next

Going forward we will need a long term monitoring of soils to detect changes in soil health over time and to act as an early warning system before problems arise on farms. Simultaneously we need practical management solutions for protecting the health and quality of our agricultural soil or for remediating soils which have been previously damaged. This knowledge can be integrated with knowledge transfer services to provide advice to farmers and farm advisors. We have made a good start but we have a long way to go!

Acknowledgements

Funding from DAFM, we acknowledge the farmers for providing access to field sites across Ireland, Laboratory and field staff at Teagasc.