Dr. Patrick Forrestal of Teagsc Johnstown Castle outlined that there are three pillars of soil health at the recent Irish Tillage and Land Use Society’s (ITLUS) Winter Conference.

In order to maintain soil health all three pillars need to be adhered to and any pillar can only partially compensate for neglecting another.

Those three pillars of soil health are:
  • Physical;
  • Biological;
  • Chemical.

“We have entered an era where I think we need all tools in the toolbox to be able to sustain production. You can have great or poor soil in both organic and conventional systems,” Patrick noted.

There’s a recognition there that we can’t have this take, take attitude and expect our soils to remain healthy and productive.

In order to improve soil health we need to understand the pillars of soil health.

Biological pillar

The biological fraction of the soil is made up of ‘the macro’ and ‘the micro’. The macro fraction of the soil is made up of larger organisms like earthworms, but the micro fraction is made up of tiny organisms like bacteria.

Paddy explained that if you counted the entities in one teaspoon of soil you would be counting for six and a half years. In order for biological processes to take place in the soil these organisms need to be protected.

Chemical pillar

The chemical pillar of the soil is made up of enzymes. Paddy described these chemical enzymes as the “jaws” of the microbiota. The chemical enzymes that these microbiota secrete breakdown the substances around them and speed up the rate of reactions in the soil.

Nitrogenase is an example of one of these enzymes, it is used in the nitrogen fixing process in legume crops.

Physical pillar

Texture, structure and aggregation are fundamentals of soil health.

“You can’t do a huge amount to improve the texture of soil, but if you have brown water running out of your fields during the year you’re losing a portion of the clay fraction of the soil, which is really a tremendously important and powerful part of the soil fraction that you have,” Patrick explained.

Organic manures

Adding organic manures to the soil can help all three pillars.

“The addition of organic manures to the soil – or green manures – feeds the communities in the soil and the soil food web,” Patrick explained.