Soil health: looking after what you’ve got

Soil health SM Farm

Soil is every farm’s greatest asset. It’s a multi-functional resource and supports many ecosystem services, including food production; nutrient cycling; carbon storage; water purification; and, a habitat for biodiversity.

‘Soil health’ is a term that is being discussed more and more by farmers, growers, agronomists and researchers but what does it really mean. What is soil health?

Tara Meeke, Land Management Technologist at the College of Agriculture, Food and Rural Enterprise (CAFRE), said: “It is the capability of soil to function as a living system which sustains plant, animal and human health.

“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 per cent of soils healthy by 2030.”

Getting the most from your agricultural soils means actively managing them and making changes to prevent damage and build soil fertility.

Investing in soil health is a ‘win-win’ situation for farmers. 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.

Tara Meeke continued: “Knowing the condition of your soils is the key to making informed management decisions on-farm.

“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 per cent 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 (20cm x 20cm x 20cm) 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.

Examine the structure of the soil particles, rooting depth and colour/smell of the soil. This will allow you to determine if compaction and/or drainage is an issue.

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.

Tara Meeke concluded: “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 and a (20cm x 20cm) 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 per cent of the farm each year to improve pH levels.

“If soil pH or nutrient indexes need 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.”

For further information on improving your soils go to the CAFRE website or contact your local Agri-Environment Adviser.

n www.cafre.ac.uk/industry-support/knowledge-transfer/project/sustainable-soil-management/improving-soil-and-sward-performance/

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