Soil Health in the river Beult Catchment
About the Project
Soil is a farmer’s most important asset, and is also a vital element in the ecosystem. For both farmers and wildlife, healthy soils can be the foundation for a healthy landscape. So in 2020, farmers from the Upper Beult Farmer Cluster have been investigating soil health.
The Soil Your Undies soil health test is a novel method of gauging soil health through assessing the level of activity of the soil biology. This simple test requires a pair of cotton underpants, a spade, a marker post and the desire to find out what is really going on under your feet.
You can download the ‘how to’ guide here.
Aims
- To use the Soil Your Undies method to experiment in
soil health testing - To get famers in the cluster thinking about their soil biology
and make the link with healthy crops and profitable farming
Method
For this experiment, farmers took home a large pair of white cotton underpants and at the end of March, buried them in one of their fields.
The idea for this experiment was to leave the underpants in the soil for a couple of months, and see how much they degrade to discover the level of biological activity going on. Soil full of fungi, bacteria and invertebrates is a healthy soil, so the idea is, the less of the pants left after two months, the healthier the soil! Healthy soil means healthier crops, which will be less susceptible to disease and require fewer chemical inputs, a win-win for the farmer and for wildlife!
Results
Four farms have managed to locate their buried treasure and dig them up. A few more are still searching their fields, and a few are planning to bury their pants later this year.
We think the weather and clay soils may have impacted the pants degradation (or lack of) as much as the soil biology.
Graham and Amy at Ramstile Farm buried their underpants in semi-improved meadow, out of reach from any grazing stock on his mixed livestock farm. Looks like the biology was starting to do its thing with some considerable holes showing up. Underpants modelled by Graham (left).
Martin and Maryann at Green Farm rose to the challenge and buried their underpants (cut in two) in the unimproved permanent pasture on their farm in Shadoxhurst.
After eight weeks, the pants are almost wearable! What caused this lack of degradation? It’s likely to be heavily influenced by the extreme weather in spring, which lurched from saturated soils to drought in a short time period.
Mixed with the heavy clay found on Green farm, it seems it will take a bit longer for the biology to work its way through these
Alan Higgs at FGS’s Stanford Bridge Farm also split his pants and buried the two halves across two field types (arable and permanent pasture).
The arable field results show that some of the cotton underpants has been torn away, but are mostly intact. In contrast, the permanent pasture looks to have had a lot of activity!
So what’s going on at Stanford Bridge that has led to so much activity in the pasture?
Alan very modestly thinks this could be partly down to his positioning of the pants. He carefully chose a spot of slightly higher ground, which wasn’t saturated in the heavy rain.
This meant that as the ground warmed up in spring, the worms, fungi and other microbes were able to really get to work
At Little Omenden Farm, David and Elizabeth Harrison buried the full underpants, rather than chopping it into pieces, which may have made it harder for the soil biology to break down the cotton.
These were buried under arable reversion permanent pasture, which has a good plant diversity. However, similarly to Green Farm, they also think the characteristic clay of the Low Weald, coupled with the extreme weather, made the conditions tough for much microbial activity to have an impact in the short time frame
Additional Factors
Underlying soilscape
The underlying soil type in the Upper Beult is likely to have had a big impact on this experiment, and from the
Magic Maps soilscape layer (see below), the predominant soil for all farmers in this area is defined as:
Slowly permeable seasonally wet slightly acid but base-rich loamy and clayey soils.
Magic Maps, Soilscape for Mid and South Kent, Weald clay across the Upper Beult catchment. Red dots denote the rough locations of the four farms where the pants featured here were unearthed.
Weather
It’s very likely the unusual weather also played a role in how active the clay soil could be, with three times the average rainfall recorded in February, and extreme drought in May. Resulting in a swing from saturated claggy soil to something bone dry and cracking! The graph below shows just how unusual this spring’s rainfall was!
Regional rainfall for Kent, as recorded by Southern Water
Outcomes
This was never a strictly scientific experiment, but a somewhat fun way to start thinking about soil biology!
The results aren’t enough to draw proper conclusions that the soils tested are simply good or bad. It’s clearly much more complex than that. However, it can only be a good thing to be considering soil health on the farm more deeply.
Here is a link to a useful talk on ‘how to reduce inputs’ from the AHDB, which is really insightful on the topic of soils. This includes a practical discussion among farmers in different parts of the UK about improving their soil structure. The below image was taken from Simon Cowell’s presentation, showing organic matter build up on his clay soils, through his adoption of various regenerative practices.
This screen shot from his presentation, shows clearly where the worms were mixing the soil, with some of the rich topsoil infiltrating the denser clay subsoil
Soil structure improvement, photo from Simon Cowells presentation on AHDB webinar, How to reduce inputs.
Takeaway ideas
Could some of the principles of regenerative agriculture help improve the clay soils of the Beult?
1. Increase crop diversity.
2. Armour the soil surface.
3. Minimise soil disturbance.
4. Continuous living roots.
5. Livestock integration.
6. Mob grazing/ holistic management.
Map showing farms who have buried underpants on their farms.
