Monitoring soil health on farm

Date published: 16 July 2025

“Proper functioning of the soil depends on all three aspects working together. To optimise and better understand soil health, it must first be measured to get a starting point.”

The Soil Nutrient Health Scheme (SNHS) provides all farmers in Northern Ireland with invaluable information about the chemical status of the soil in their fields. But how do farmers measure the physical and biological status of the soil in their fields?

In autumn 2024, CAFRE initiated a project to measure soil health across the CAFRE farms at Greenmount Campus and Glenwherry. Two simple measures were chosen alongside routine soil analysis. “It was decided a Grass VESS (Visual Examination of Soil Structure) evaluation and completing worm counts would be two methods of analysis that could be compared across the different fields. VESS can give a clear assessment of soil structure, while the worm counts provide a guide to the biological health of the soil,” commented Sinéad.

In each field three soil pits 20x20x30cm were dug and their location GPS recorded.  “It is important to pick a representative number of places in a field to assess or measure, as fields can vary in their slope and soil type which can affect the number of earthworms and structure of the soil,” added Sinéad.

CAFRE used VESS and earthworm information and calculated an overall score. This is based on the soil health scorecard developed by AHDB to benchmark and determine how the fields on the farm are performing from a physical and biological perspective.

Initially 54 fields were assessed, which included 20% of fields on the Beef and Sheep Centre: 22% of fields from the grassland area at the Dairy Centre, 35% of arable fields and 14 improved in-bye fields at the CAFRE Hill Farm. Overall, of the fields sampled, 48% had good soil structure with 50% moderate soil structure and 2% poor soil structure. Earthworm numbers were typical or intermediate for both the beef and dairy farms with 84% of fields on the arable platform surveyed having good or intermediate earthworm numbers. However, two of the arable fields had low earthworm numbers and this, coupled with moderate soil structure, highlighted that something needed to be done to improve the soil health of the fields in question. 

As a result of the VESS and earthworm assessment for the arable field shown in Photo 1, CAFRE Crops Technologist, Tanya Maguire took remedial action by working with the Farm Team to plant a cover crop of leafy turnip and fodder rape in September 2024. This was sown after winter wheat had been harvested, to improve worm numbers and soil structure.  The structure of the soil before the cover crop was classified as “moderate and platy” with large aggregates, low porosity and low earthworm numbers.  However, after a period of three months the cover crop had established (Photo 2), earthworm numbers had increased, and soil structure had improved from "platy” to visible smaller aggregates with more pore spaces.  The benefit to soil structure of having a living root in the soil to feed soil biology and improve soil structure will be of carry over to the next crop.

DAERA’s Farming with Nature Transition scheme is now open until 4^th August and farmers with land designated as arable on LPIS can apply for funding (£225/ha) to establish a multi-species winter cover crop on their arable fields - improving soil health and water quality.  Applications can be made through DAERA Online services as long as the business does not currently have a live EFS agreement. 

Visual evaluation of soil structure and worm counts are quick, easy and cheap ways of determining the health of your soil and can provide benefits in terms of production and sustainability whilst protecting the environment. Autumn and spring are the best times to assess earthworm numbers on farms.

Why is soil health important?

Good soil health is crucial for efficient and sustainable food production. Healthy soils will cycle nutrients better for the growing plant, increase water infiltration and storage while also providing further ‘ecosystem services’ which help regulate climate, sequester carbon and improve water quality.

Farmers must consider carbon, phosphorus, water quality, ammonia and biodiversity whilst also producing food sustainably and profitably.

Management of soil will dictate how well these functions are delivered. Soil type, cultivation, drainage, inputs, crops grown, livestock and machinery operations all impact on the physical, chemical and biological status of soils. 

For further information about how to measure the physical and biological status of your fields, contact your local CAFRE Adviser.