Soil Health: The how, the why and future directions

As part of LEAF’s ten-year plan for the development of LEAF Marque, we are focusing on soil health. University of Reading, Masters student, Sam Brook is carrying out a scoping study for LEAF and here he discusses the outcomes of the LEAF member survey and next steps.

My previous blog focused on the literature review and farmer interviews, here I’ll summarise the survey results and discuss conclusions and next steps.   LEAF wanted to know about their members’ views on the following six key areas related to carrying out earthworm counts, visual soil assessments and soil erosion assessments.

Scientifically defensible as a proxy for soil health

Currently widely practised by farmers

User-friendly

Able to produce results that are useful and meaningful

Time and cost efficient to carry out

Able to produce results that can be used as an auditable benchmark for LEAF

What LEAF farmer members are doing

A high percentage of LEAF farmer members use soil-health tests (SHT) of some description, usually on a time-scale of every 3-4 years. Visual soil assessment (VSA) is the most popular SHT, followed by earthworm counts (EWC) and then a distant third is soil-erosion assessment (SEA). The results can be considered encouraging from a SHT control-point perspective, although this positivity is tempered by the fact that only 16% of respondents test soil health annually. 

What is user-friendly

VSA and EWC are generally well-regarded by farmers in terms of ease-of-use. SEA polled considerably worse, suggesting a gulf in usability between VSA and EWC on the one hand, and SEA on the other. This data corroborates the findings uncovered in the literature review in my previous blog.

 Producing useful and meaningful results

All three tests polled poorly when it came to farmer opinion on the reliability of the tests to monitor soil health. However, it is not clear whether this is the fault of the tests, or due to the interpretability of the notion of soil health itself. Only half of respondents considered these tests helpful and capable of capturing soil health. Again, there was a clear divide in terms of farmer opinion on the usefulness and meaningfulness of VSA and EWC versus SEA

Time and cost efficiencies 

 EWC and VSA were deemed cost-efficient by respondents, as opposed to SEA. However, due to low equipment costs, time is a more important factor. Taking the concept of ‘time is money’, it is difficult to discern between the two limitations. None of the three tests are viewed by farmers as usable across the whole farm – probably due to the high time-demands placed on farmers – which means the question of scale for the LEAF control point is very important. It should be comprehensive enough to be meaningful, but also not over-ambitious and burdensome for farmers. 

Achieving auditable benchmarked results

EWC and VSA polled as SHTs that produce reliable and auditable SH data, whereas SEA did not. Once again farmer-respondent opinion reflects findings of the literature review. Farmers seeing the auditability of the tests is a positive sign as it suggests there is good buy-in to the concept of using these tests to measure soil health. 

Conclusions in brief 

Overall, the conclusions to the research questions can be summarised as follows: 

Although the project is limited by scope of the survey and most crucially by the number of respondents (5% of LEAF farmer members completed the survey), I think that it can be considered successful in answering the 6 main objectives that LEAF wanted to cover. During the course of the project it became apparent that there were certain flaws and oversights, but it has been a useful fact-finding exercise that LEAF can now use to take things forward to the next stage. Based on my experience of my research, I can suggest the following course of action: 

Next steps

From a personal point-of-view, it has been an interesting and informative undertaking; I certainly hope it has been as useful for LEAF.  I know that based on this work, a recommended control point has been added to the next version of the LEAF Marque Standard, which goes out for public consultation on the 30th November - you can get involved here.  These were big questions that were asked, and whilst I did my best to answer them, I think it’s fair to say that it was not an easy task: soil health does not easily lend itself to simple, straightforward conclusions! That aside, I hope you have found the project interesting, and thank you very much to all those of you who took the time to fill out the survey (and even more so those who I interviewed). 

My work with LEAF is now over for the time being but I start work as a trainee tomato grower in December on a LEAF Demonstration Farm, so my relationship with LEAF is set to continue into the future!

A summary report is available here and the full set of data available here. If you'd like a copy of Sam's full dissertation, please email alice.midmer@leafuk.org