The aim of the project is to provide tools and measures that enhance our understanding of the impact of farm practices on soil organic matter and soil carbon.
What will the project be doing?
The project is being funded through Agri Tech Cornwall and is a partnership project between Duchy College Rural Business School and Rothamsted Research North Wyke.
The project will:
Develop a robust sampling methodology for measuring soil organic matter and soil organic carbon on-farm;
Investigate the relationship between soil organic matter content and ‘proxy’ measures that farmers can use without laboratory analysis;
Investigate the relationship between current and historic management practices, soil carbon and farm economics;
Develop knowledge exchange tools for farmers and advisors in relation to soil carbon management and planning.
How can I get involved?
The project is working with farmers and growers across Cornwall and the Isles of Scilly. To get involved contact the project team at the Rural Business School on 01579 372376 or firstname.lastname@example.org
The results from the project as well as information on the research and methods will all be available through this page as the project progresses.
Below is an explanation of some of the proxy tests that we are carrying out on-farm to see whether there is any relationship between these tests and levels of soil organic matter.
Soil Health Testing
To investigate the soil carbon levels in your fields, you can carry out soil sampling for laboratory analysis as with conventional nutrient testing or you can use proxy measures of soil health.
These proxy measures include worm counts, visual evaluation of soil structure (VESS), aggregate stability, infiltration rates and the burying of cotton pants.
Worm counts will give an indication of soil health as they are impacted by pH levels, waterlogging, compaction, tillage and organic matter levels.
What is the best way to assess worm activity in my field?
Sample at three locations across the field.
Extract a soil block one spade depth and width onto a plastic sheet
Sort through the soil and count and identify worms.
Return worms and soil.
There are three main types of earthworm:
Epigeic – litter-dwelling, small red worms
Endogeic – topsoil-dwelling, pale and green worms
Anecic – deep-burrowing, large dark worms
These worms play different roles in maintaining soil health; epigeic worms are important for carbon cycling, endogeic are important for soil aggregation and nutrient availability and anecic worms create deep burrows that improve aeration, infiltration and root development. It is therefore important to have worms from each of the groups in your fields.
A guide to identifying worms can be found at AHDB’s Great Soils website.
Dr. Jackie Stroud at Rothamsted research is running a project looking at worm counts on farms across the country. To find out more visit WormScience.org
Aggregate Stability refers to the degree to which a lump of soil maintains its structure when submerged in water.
Healthy soil will have a low aggregate stability score, organic matter and carbon acts as “glue”, binding soil particles together to give a good soil structure. If an aggregate has a high score, the soil is more susceptible to erosion and compaction as there is nothing holding particles together.
While you have the soil block extracted for the VESS test, take a fistful of soil home with you
Place the soil on a tray to air dry for 3-5 days
Once dry, extract three lumps 3-5mm in diameter and place them in a dish of water so they are fully submerged
Score the samples using the aggregate stability score (below) after 5 minutes and 2 hours
Aggregate Stability Scores:
0. if the lump remains intact,
1. if the lump collapses around the edges but remains largely intact,
2. if the lump collapses into angular pieces,
3. if the lump collapses into small rounded pieces, forming a cone,
4. if the lump completely collapses into single grains.
The rate at which water infiltrates into the soil is a good indicator of soil structure, particularly compaction.
Healthy soil has a short infiltration time, because pore spaces allow water to infiltrate down into the soil. These pore spaces encourage root development, soil aeration and the retention of water for use by plants.
Compacted soil has fewer pore spaces and so infiltration times will be longer.
Choose three sites across the field that represent ‘normal’ soil conditions (not in gateways, tramlines or tracks), clear away any vegetation or residue from the surface.
Insert a cylinder (e.g. tin can with both ends removed) a few inches into the soil
Pour 107ml of rainwater into the cylinder and start the stopwatch
Time how long it takes for water to infiltrate, stop timing when the water is gone and the soil is glistening
A detailed guide to carrying out the infiltration test can be seen below and here
Burying cotton pants is a good way of looking at the microbial activity in the soil. Healthy soil supports communities of microbes that are important for decomposition and the cycling of carbon and nutrients.
When you have dug a soil pit for the VESS test, place a pair of white, 100% cotton pants in the pit
Make sure the pants are spread wide in the pit, not scrunched up at the bottom
Fill in the pit and mark the location
Return in three months to dig up the pants and look at the degradation
Healthy soil will have lots of microbes that will break down the pants and create holes in them. Unhealthy soil won’t have the important microbial communities and the pants will remain intact.
Check out the hashtag #soilmyundies on Twitter to see how the test works in the field.
Agri-tech Cornwall & the Isles of Scilly is a £10m project to increase Research Development and Innovation in the Agri-tech sector across Cornwall and the Isles of Scilly. Running to March 2020, it is funded by the European Development Fund, Cornwall Council and the Council for the Isles of Scilly.