Thanks to everyone who took part in the Spring 2018 on-farm pilot worm survey. This pilot study is now the AHDB factsheets available to download below. This is a thorough test for those with 60 - 180 mins time per field to perform a detailed earthworm survey.
A quick summary #60minworms infographic is available & FAQ below.
The results have been analysed and this study has been submitted to an academic journal for publication.
The scientific analysis of the #60minworm survey (Spring 2018) suggests that a less intensive sampling effort (#30minworm survey) can provide a good evidence for basic earthworm biodiversity in a field.
How has this summer drought impacted earthworm populations and how quickly will they recover? Please help by taking part in the #30minworms survey.
As always, any comments and feedback gratefully received.
What was the #60minworms survey?
This was a Spring pilot study (March-April 2018) to support farmers interested in measuring soil health using their earthworm populations. It involved digging 10 soil pits and counting and analyzing the worms in-situ. The data was then emailed to me, I sent back the results and we had a 'wormshop' in May 2018 to discuss how to improve the method etc.
It isn't just a worm count. This survey informs on the presence and types of earthworms in the soil - this is a useful indicator of over-cultivated, underfed soils, as two groups of worms - surface and deep burrowers can become rare or even locally extinct in over-worked soils.
How did people rate the #60minsurvey ?
I'd hoped for 100 fields to be tested and I was delighted with 126 field results returned. The method and results feedback were highly positive, the method being easy to follow with people having good confidence in the data they collected. A key training need was identified - better support for separating adults/juveniles and determining the ecological group of the adults was needed. To help with this I've made an earthworm ID quiz for people to practice, and a YouTube video demo - plus encouraged people to check out the OPAL species guide. A few people reported signs of deep burrowers - but none found in their soil pits. To solve this potential underestimation I've modified the method to include these deep burrowing indicators - middens and pencil size burrows. The workshop participants were positive about the test - 100 % would recommend and 100 % would do the test again. There was a big interest in digitizing the method, so I've made the new protocols available by .pdf and there will be a web-form for data entry when worm sampling season starts.
Now, not everyone who asked for a #60minworm booklet took part. I asked a few people and it came down to time; and it did take someone 3 hours to complete the #60minworm survey. Thus, I've been looking at the trade-off between data quality, sampling effort and time - to best support participation rates - which indicated halving the number of sample pits and simplifying the interpretation could work well and has led to the #30minworm pilot study this Autumn.
This is very much a collaborative process - providing data helps me to look at general trends to provide information on how to realize soil health in practice, and if you have method feedback please do share so that the protocol is practical and feasible. To date, the #60minsworm survey was highly rated for it's usefulness to informing on soil management practices by participants.
What did you find out from the #60minsurvey ?
The results were in agreement with the body of scientific literature that tillage is detrimental to earthworms. None the less this is subject to local conditions, the top 10 fields in the survey were managed under NoTill, MinTill and traditionally ploughed. This is why monitoring is so important, particularly because. earthworms can improve plant productivity.
Once the paper has been peer-reviewed and published it will be available to answer more specific questions - so please check back for updates.
What will the Autumn #30minworm test show?
This is a simplified protocol so I've simplified the analysis. The threshold for a 'green/pass' score is 4/5 soil pits containing at least one earthworm (adults and/or juveniles) AND at least 1/5 soil pits contain at least one adult surface, topsoil or deep burrower in an arable soil. There is a lower threshold for horticultural soils. This will provide information on how widespread earthworms are in a field; and their basic biodiversity.
The long drought will likely impact earthworm populations. The closer the earthworm type lives to the surface, the more likely it is to have been negatively impacted by the dry soil. Taking part in the survey will help to understand the impact and recovery of these important ecosystem engineers.