Soil health: ‘The most valuable tool on your farm is your spade’

‘Soil health’ is a term coming up more and more frequently among farmers, growers, agronomists and researchers, but what does it really mean – and how do you know how your own farm is faring?

Tara Meeke, land management technologist at the College of Agriculture, Food and Rural Enterprise (CAFRE), explained that soil is every farm’s greatest asset.

“It is the capability of soil to function as a living system which sustains plant, animal and human health,” she said.

A healthy soil system requires the chemical, physical and biological properties of the soil to work in harmony. The EU has set a target to have 75% of soils healthy by 2030.

She explained improving soil health increases crop yields, provides resilience to climate change and aids carbon sequestration.

“Regularly walking your fields will help identify potential issues, such as areas of poor crop growth, ponding, run-off or erosion,” Meeke continued.

“To check the chemical properties of your soil, you’ll need to take soil samples and get them analysed.

“This should be carried out every four years to test pH, P, K, Mg and organic matter content.

It doesn’t need to be the whole farm at once. Look at fields that aren’t performing or any that you’re planning to reseed. If you test 25% of your land every year, in four years you’ll have tested it all.

“The most valuable tool on your farm is your spade. Lifting your spade and digging soil pits (20cm³) is a great way to check the physical condition of your soil. It is best to assess the soil when moist, typically in spring or autumn.”

Meeke explained farmers should examine the structure of the soil particles, rooting depth as well as colour and smell of the soil.

“This will allow you to determine if compaction or drainage is an issue,” she said.

A well-structured soil has round crumbly particles that can be easily broken up between your fingers and plant roots that go down through the soil.

“Also, the soil should smell earthy or have little odour at all. If the soil appears to be clumped together, difficult to break apart and the roots are restricted to the top few inches there may be a compaction problem.

“If the soil smells pungent it is a good indication there is poor drainage or lack of oxygen in the soil.

“To assess the biological health of your soils look no further than the earthworm. They are a key indicator of soil health as they are sensitive to changes within the soil environment such as pH, waterlogging and compaction.

Counting the number of earthworms in your soil pits provides an indication of soil health – a (20cm³) soil pit should contain 7-10 earthworms.

“Once you have identified the condition of your soils it is important to record this information and draw up a plan to improve soil health.

“For example, liming 20% of the farm each year to improve pH levels. If soil pH or nutrient indexes need to be addressed, then an application plan should be determined using RB209.

“To make optimal use of fertilisers and manures, the CAFRE Crop Nutrient Calculator which is available through DAERA online services, can be used to calculate crop nutrient requirements and produce a nutrient management plan.

“If drainage is required it is advised that the drain layout of the field be mapped so that they can be maintained in years to come.”