In recent updates from the Footprint Farms, we’ve shared insights into the progress and implications of chemical soil test analyses. While understanding the balance of chemical constituents in our soils is vital for optimising the efficiency of inputs, there’s also a growing awareness of the importance of nurturing the biological component – the living army within our soils.

A complex web of life

Bacteria, fungi, archaea, protozoa, nematodes, earthworms, and other microorganisms found in the soil pack a serious punch in terms of cycling nutrients and improving soil structure. They are also unique and fascinating creatures.

The springtail, for example, one of the most abundant microscopic insects in our soils, derives its name from a spring-like tail structure it keeps tucked away under its body.

When threatened, it releases this spring, causing it to execute up to 370 backflips per second as it spins through the air to evade danger. In addition to these little-known acrobatics, springtails play a crucial role in maintaining soil health, both by consuming dead material and by keeping populations of soil bacteria and fungi in balance.

Similarly, bacteria are unsung heroes of soil health. Healthy populations of bacteria can release nutrients for plants, fix nitrogen, enhance soil structure and aggregation, and improve water infiltration and retention.

Bacteria also provide a food source for other soil microbes, such as protozoa and nematodes, which in turn play important roles in balancing soil biodiversity and boosting soil health.

In healthy soils, this diverse army of life exists within a complex web of earthworm burrows and fungal hyphae, both of which also aid in root and water infiltration, naturally boost soil fertility, and buffer against compaction, drought and erosion.

Maintaining the living army in soils

Unfortunately, some management practices can damage the living components of soil over time. Pesticide application and the buildup of pesticide residues in soil, for example, can impact on the health and diversity of soil life.

As soil biodiversity dwindles, its capacity to provide essential ecosystem services also diminishes. This decline often results in decreased soil productivity, necessitating larger quantities of costly chemical inputs to sustain yields.

Paradoxically, this reliance on chemical interventions further exacerbates the degradation of soil biology.

Footprint Farmer Gareth Culligan is passionate about maintaining both optimum chemical balance and healthy biological activity in his soils. Gareth uses direct drilling, cover cropping and companion cropping on 600 acres of arable farmland in Co Louth.

Luckily, there are many simple ways to break free of this cycle and ensure this army of creatures continues to boost soil health and promote plant productivity for free.

Minimising the use of chemical inputs, as well as boosting soil organic matter, avoiding soil compaction and erosion, reducing or eliminating ploughing (where possible), increasing plant diversity, and keeping soils covered are all practical approaches our eight Footprint Farmers are implementing to nourish and sustain the living element of their soils.

In doing so, they are taking steps to ensure the long-term productivity of their farms.

Read more on recent results of chemical soil analyses of N, P, K and other nutrients on the Footprint Farms.

Top tips: get earthworms working for you

Earthworms eat their bodyweight in soil every day. In doing so, they break down organic matter, naturally fertilise the soil and make nutrients more readily available for plant roots.

They also aerate soil through their burrowing behaviours, and exude a sticky mucus which helps to form soil into ‘crumbs’, improving water and root infiltration and bolstering the soil against compaction.

On the basis of these freely provided ecosystem services, in its 2008 Benefits and Costs of Biodiversity in Ireland report, the Department of Environment estimated the marginal value of the earthworm to the Irish economy each year as in excess of €2.6bn, while research conducted at Colorado State University in 2023 revealed that the earthworm contributes to as much as 6.5% of global grain production.

Concerningly, land drainage, the use of pesticides and chemical fertilisers and repeated ploughing can all damage earthworm populations.

In the UK, a recent study by the British Trust for Ornithology (BTO) estimated that the population of earthworms has declined by over 30% in just the last 25 years, with potentially serious consequences for soil health and productivity.

Fortunately, earthworm populations will bounce back if given the chance: minimising the use of chemical fertilisers, pesticides and herbicides, keeping soil covered, and boosting soil organic matter are all practical steps that can be taken to boost earthworm populations.

Learn more: soil-enriching power of fungi

Fungi that naturally exist in healthy soils play key roles in breaking down organic matter, improving soil structure and releasing nutrients for plant growth.

Fungi also have beneficial relationships with the roots of 80% of land plants. These ‘mycorrhizal fungi’ release enzymes that unlock plant minerals and convert them into a soluble form for plants. In exchange, plants provide fungi with carbon.

The application of fungicides and chemical fertilisers can damage these fungal networks, inhibiting their ability to enrich the soil and unlock nutrients for plants.

Minimising the use of chemical inputs, increasing soil organic matter, and switching to minimum disturbance methods of crop establishment where possible are all actions that can help to get fungal networks working for you – boosting both soil health and plant productivity.