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April 2019

Earthworm Engineers #1 – Ecosystem Services

5184 3456 Sectormentor for Soils

Welcome to the first post in our Earthworm Engineers series where you can learn from some of the best science about the value of these amazing creatures. We’re so excited that Professor Jenni Dungait is now the editor of the European Journal of Soil Science – and she’s made some important earthworm papers open access for a month. We’ve picked our favourite four and summarised them in this blog series.

Access the earthworm archives in the European Journal of Soil Science, to learn more about the science behind on-farm worms!


#1: A review of earthworm impact on soil function and ecosystem services 

This paper reminds us of the many reasons why earthworms are farmers’ best friends. We can separate earthworm species into three categories: surface-dwelling worms (epigeic), deep-burrowing worms (anecic), and network-creating worms (endogeic). All three of these worm types play an important role. In their soils, earthworms are considered ‘ecosystem engineers’, and they earn this title for several reasons…

First, earthworms actually create soil! Worms feed on leaf litter on the soil surface then bury the organic matter into the soil, allowing it to be mixed and decomposed, and eventually incorporated as soil organic carbon within soil aggregates. This same process also allows for nutrient cycling in the soil, which is helped by the soils’ increased surface area due to the networks of earthworm channels. In eating soil and moving it around, worms have even been shown to heal soils that are polluted, by breaking down the contamination.

The presence of earthworms improves the soil structure, as the pore network created allows for a higher ‘bulk density’ of stable aggregates. This pore network can also improve plant root penetration, and the water infiltration ability of the soil, by creating space for the water. The increased drainage and the creation of water-stable soil aggregates can also reduce runoff on farms, as well as soil erosion by up to 50%.

Photo from Jackie Stroud’s Earthworm Quiz on wormscience.org

As earthworms burrow into the soil and bury organic carbon, they also help the process of carbon sequestration – the locking up of of CO2 from the air into the soil. But this soil carbon can be re-released again as greenhouse gases, especially when the soil is disturbed during ploughing. The process of building up carbon in the soil is complex, and varies depending on how much organic matter is available to the worms on the soil surface.

Considering all of these earthworm endeavours going on beneath our feet, it’s unsurprising that this paper finishes by reporting that the presence of earthworms has been widely shown to improve the growth of plants above ground. Now we’re completely convinced that earthworms really are the engineers of their ecosystem!

If you’re not all wormed out – read part 2 of our Earthworm Engineers series here.


Earthworms are one of the best indicators of soil health – find out how to monitor earthworms on your farm.

Will Godwin – Hampton Estate

1440 1079 Sectormentor for Soils

The beautiful family run Hampton Estate is nestled in the sandy soils of Seale, near Farnham in Surrey. Most of the farmland is in woodland or grass and twenty years ago Guernsey dairy cattle grazed the estate. The family have since switched to a Sussex cattle herd and started producing grass fed beef to sell direct to their local customer base. Their cattle are raised on tasty grass and lovely Surrey sunshine! Hampton Estate are members of the Pasture Fed Livestock Association and in the process of having their beef pasture for life certified. Pasture fed systems with good grazing management can be very regenerative for soil health. Hampton have started using Sectormentor for Soils to monitor and understand how soil health is changing across their farmland.

The estate has some very special gardens filled with hops! This speciality crop has been grown in the local area for hundreds of years, despite a lot of production being wiped out by a fungal disease called verticillium wilt. Many other farms gave up their hop gardens, but Hampton has maintained growing this traditional crop with high biosecurity measures. Their hops are used in three major breweries across the country. The infrastructure required to grow hops is extensive and to fit in with the natural landscape Hampton uses tall poles made of chestnut from their own woodland.

Hampton are developing their farm strategy around building soil health and improving their sward. Using Sectormentor for Soils they can create a baseline for where their soil health is at now and give them an idea of where they want to go. Growing good grass is essential for their pasture fed cattle and so one approach they will take is to increase species diversity and deeper rooting plants in the sward. This will increase their resilience in times of drought as deep roots can reach water and nutrients further down in their sandy free draining soil. A more diverse range of broadleaf plants and root systems will increase the potential to sequester carbon from the atmosphere and put it into the ground. Hampton is monitoring the % of different plant species and their density to see how this changes over time in their pasture fields. As they collect more information about their pasture with Sectormentor for Soils they will be able to compare plant species readings with soil structure and earthworm readings to see if there are any trends and links in their improvement.

“I’d been looking for a tool to monitor soil health just like this, I’d tried other tests but they were always so complex and involved lab testing. It’s great to have a set of simple tests that I can do easily myself.” – Will Godwin, Hampton Estate

We spent the day soil monitoring pasture fields under different management approaches with Will Godwin. Will is part of the estate management team and works very closely with Bridget and Bill Biddell who own and manage the Estate on behalf of the wider family. Heading out to the field with Will and Bridget was great fun and the excitement about digging holes and hunting for worms was palpable! Will had expertly crafted an infiltration rate pipe from a piece of drainpipe, sharpening one end to make it easier to get into the ground. He used an old water bottle with 444ml of water marked on it to ensure the exact same amount of water was used each time. An old dustbin lid made an excellent examination tray for the soil block and Bridgett didn’t seem to mind us using her freezer bags to collect samples for the slake test!

We started on a very sandy permanent pasture field grazed throughout winter by their steers and very poached up in places. On this field we found no worms at all! This meant Will recorded an earthworm count of 0 in Sectormentor for Soils and we all agreed this is definitely an opportunity to improve how the soil on this field is managed to increase earthworms for the next time it is monitored. Next we headed to a permanent pasture field being rested after grazing last year which had an abundance of wigglers, seventeen in one soil pit, and even a dung beetle popped its antlers up. At the time we didn’t realise it was a dung beetle, but took a photo of it using Sectormentor for Soils so Will could look back at a later date to identify the beetle. This field had a dense thatch of grass on the surface which slowed the infiltration rate down considerably. The third field we tested was a grass field cut every year for hay which had a few worms but an exceptionally fast infiltration rate. In addition to these fields Will plans to monitor two more pasture fields and one hop garden.

Going forward Hampton plans to start a new grazing system, to improve sward quality and soil health across the estate. Changes in the way the herd is managed and trying mob grazing to encourage tall grass and deep root growth are central to the strategy. Over in the hop gardens, although they cannot return the biomass from the hop plants back to the soil due to the verticillium wilt disease risk, there are plans afoot with Rob, their Agronomist, to plant green manure cover crops in between the rows of hop plants. Verticillium wilt only affects broadleaved plants and to avoid attracting it to the garden the cover needs to be a cereal to mitigate this risk, so rye and oats are good options. The cover crop will anchor the soil, protecting it from erosion, photosynthesising and putting nutrients into the soil.

Sectormentor for Soils will help Hampton monitor how their soil is changing as they experiment with new farm management approaches to improve soil health. For example, with a new approach to grazing the fields over winter, such as mob grazing, Hampton will hope to see an improvement in earthworms, sward density and soil structure. All of these are what we call ‘soil health indicators’ and are easily monitored using soil tests with Sectormentor for Soils. All the information Hampton collects using the Sectormentor for Soils app is visually displayed on their online account making it easy to look back at their soil health records and analyse how things have changed over time.

What are Will’s management objectives:

  • Improve soil health across the estate
  • Increase grass and broadleaf species
  • Understand best grazing technique to optimise grass growth

What is Will monitoring:

  • Earthworms
  • Infiltration
  • Slake (Wet aggregate stability)
  • VESS (1-5)
  • % of undesirables % of bare soil
  • % of grasses, broadleaves, no. of species of each

 

Interested in using Sectormentor for Soils to monitor soil health and manage your farm both above and below ground?

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