The soil is home to a quarter of all living land organisms from a wide range of taxa.
Nearly all soil organisms can’t make their own energy and so need to eat plant residues, soil organic matter or other soil organisms.
The majority of soil organisms are invisible to the naked eye so they are often observed by measuring what they do. Earthworms are the most beneficial macrofauna in UK soils, they’re engineers that make pores within the soil and also mix organic materials into the soil.
Within the soil there are micro-organisms which are often grouped by size, they’re collectively known as soil biota. These organisms interact with one another – larger organisms often prey on the smaller organisms and there is a complex food web below ground.
Megafauna: 20 mm upward, e.g. rabbits and rodents.
Macrofauna: 2 to 20 mm, e.g. beetles and snails
Mesofauna: 100 micrometres to 2 mm, e.g. mites
Microfauna and Microflora: 1 to 100 micrometres, e.g. bacteria and fungi
On farms, soil organisms can work together with inputs to give more effective and resilient regulation of grassland systems. However, whilst there are some general principles, there is no one recipe for management that will put all soils in good health.
To have healthy grassland soils, farmers should aim to:
• Increase organic manure inputs and provide a range of types – through careful manure management and use of composts
• Increase plant diversity – with grass/clover leys and other mixed species swards for grazing and conservation. Use mixed species for whole-crop silage
• Reduce tillage intensity – if soil structure is good, consider overseeding rather than ploughing for ley invigoration, get the timing of aeration or sward lifting right
EBLEX and DairyCo are launching a new website called Healthy Grassland Soils in March which will provide more details on soil biology...more updates in the next edition.
