Written evidence submitted by Rothamsted Research (SH0104)

NOTES FROM ROTHAMSTED RESEARCH VISIT

Visit date: 9 February

Monitoring and data

It was pointed out that measuring and determining “soil health” is a complex area for several reasons:

• Different indicators need to be measured at different timescales. For instance, soil organic matter (SOM), which contains approximately 50% soil organic carbon (SOC), reacts more slowly to interventions (over decadal timescales) compared to above-ground biodiversity that can respond within several years. This means that in many cases farmers can only realistically be paid to adopt certain actions as opposed to being paid because a difference has been measured.
• Different measuring systems can lead to different results – for example, the loss on ignition (LOI) test is one of the cheapest and most widely applied methods for measuring SOC, but there is no agreed standard protocol. Many factors may influence its accuracy, such as furnace type, sample mass, duration and temperature of ignition and the clay content of soils. Variation between different commercial laboratories can be significant. It is also necessary to understand the maximum levels that a soil can achieve – not all soils will have the same capacity for carbon sequestration for example, because of the strong influence of soil texture upon organic carbon storage capacity (coarser soils inherently store less organic carbon). When considering carbon stocks (t/ha), it is also important to have a measure of soil bulk density (dry weight / volume).
• Unlike air and water quality, where there are clearly identified thresholds for good/bad quality, it is not so straightforward for soils, due to their variety of types and usages. Some indicators – such as the soil microbiome – present challenges because there is a lack of evidence and agreement regarding whether there are organisms which indicate the health of soils and plants etc. Further, if specific beneficial organisms or populations can be identified, it is not clear the extent to which these could be managed in practical situations.
• A soil health assessment – like a human health assessment – is likely to be a mixed picture; there is no set of indicators which provide a clear picture. Measures such as the AHDB soil health scorecard have attempted to do so – although there was some debate over whether the scorecard was too subjective and simplistic. In the future, indicators may be found that act as effective proxies for other aspects of soil health. This is an active area of research at Rothamsted and elsewhere.

One participant suggested that soil scientists risk over-complicating data collection and soil health assessments. There are some things – such as the presence of SOC – that are nearly always a good thing. To some extent, with some caveats, “more is better” – it improves soil physical properties and, as microbes release nutrients from soil organic matter, less fertilizer is required for crops. However, very high levels of SOC can lead to losses of nitrate and phosphate, causing water pollution. SOC is not a pollutant or an element that needs to be maintained below a specific level.

ELM schemes ꟷ in particular the Sustainable Farming Incentive (SFI) ꟷ require land managers to assess soils and take measurements for monitoring soil health. However, there are few requirements about how this data will be used. There was agreement among participants and Members with the idea that this information needs to be fed into a national surveillance system to help monitor soil health nationally. Because not all farmers will be expected to join an ELM scheme, this would not be a full picture. However, it was noted that if farmer data could be made open to the scientific community this could be an enormously powerful data set to detect impacts of management of soil health including environmental context. Other countries such as France have better monitoring programmes which may warrant further investigation by the Committee. Many companies are now offering a soil surveying service to quantify SOC and other metrics of soil health (in part to access natural capital markets) but these data are often not publicly available and lack associated information on land use and field management.

The Committee heard about how new technologies could transform how we collect data on soils. By combining drone technology, satellite data and soil sampling, it may be possible to build a broader picture and be more strategic when sampling. The Committee was also shown how it may be possible, in the future, for farms to use sensors in the ground to measure soil attributes in real time – aspects such as moisture levels and emissions.

Advice for farmers

Due to the complicated nature of interventions to improve soil health, there was a conversation around where farmers get their advice, and how easy it is to know which farming techniques are backed by scientific evidence.

It was highlighted that most farmers rely on land managers and agronomists for advice. However, the former are often ill-equipped to provide advice on regenerative farming techniques. The latter include a range of types; some are 100% independent but some have connections with particular companies supplying specific products, so are likely to recommend products provided by these businesses. They also may specialise in the types of farming predominant in an area, and be focused solely in short-term agronomic outcomes, rather than long-term soil improvement. However, it was also highlighted that there is quality control of agronomic advisors through organisations such as the AICC (Association of Independent Crop Consultants).

Farmers currently lack clear advice on the appropriate avenue for integrating investment in soil health into farm revenue streams. Options include including land parcels in SFI, selling future carbon capture to natural capital markets (via intermediaries) or including it as in-setting to achieve net-zero for the farm. There is ongoing confusion about opportunities for blended finance from the same land parcel.

Land use

Questions were asked about how spatial planning for soils could be improved to ensure that different soils were used for appropriate purposes. It was highlighted that agricultural land classification does already exist and the government is planning to publish a land use framework. These documents will help decision-makers make better decisions about how their lands should be used, but this classification is based upon crop potential rather than soil organic carbon sequestration potential, or other ecosystem functions such as erosion or flood control, and so fails to address all aspects related to soil health. The science providing the underpinning evidence on heterogeneity in landscape properties that can inform targeting of option is now mature and available to support policy.

The government still appears to want these decisions to be made primarily at the “estate-level” which may not consider regional strategic or environmental needs – for instance, the issue of flood mitigation was mentioned that can only be addressed at a catchment scale. This potential for coordinated action by farmer clusters is currently being demonstrated in the Landscape Recovery Pilot Projects.

Alternative systems were pointed to, such as the Dutch model of spatial planning. One participant highlighted that the Landscape Recovery ELM scheme could better help regional environmental aims and help clusters of estates work together to put land to better use.

Problems with changing land use were acknowledged – for instance, one Member highlighted that land managers, choosing to plant trees for example instead of planting crops, may then force tenant farmers off their land. Other participants highlighted that large multinational businesses may similarly be encouraged to buy up agricultural land to capture the value being created by new ELM schemes. This could be a shame because:

• Many of these companies are not British and the government should be doing what it can to support British businesses
• These multinationals may be attempting to offset environmentally degrading practices elsewhere
• Any decrease in food production in the UK is likely to compensated for by imports that may well be grown under poorer environmental conditions than in the UK, e.g. on land recently cleared of natural vegetation and so emitting CO2 to the atmosphere or with adverse impacts on local biodiversity.

Encouraging changes to land management practices

While emerging soil carbon marketplaces can be a useful source of income for farmers, one participant made the argument that farmers need to be made aware that better soil health management in general – even without additional private sector financing – makes good economic sense when growing food. Financial gains (through either greater yields, or a reduced reliance on expensive inputs like fertiliser) often only emerge in the long term. This is risky for farmers as business owners. This short-term risk needs addressing. Furthermore, there may be no clear financial gains for the farmer in the short- or medium-term but the improved practice would be beneficial for longer-term sustainability of food production or for other ecosystem functions.

Potential ways in which the UK Government could help encourage a shift to sustainable practices included:

• creating a central soil strategy paper
• setting clearer and more ambitious targets. There was frustration that ambitions for sustainable soil management had been lowered to 60% of soils by 2030. There was some appetite for a clearer direction of travel that also factored in future risks of climate change i.e., prolonged periods of drought and more heavy episodic rainfall.
• Conflicts with other targets, such as net zero, were mentioned: for instance, livestock farming is good for soil health but enteric methane emissions contribute to global warming. Participants felt that to counteract this, more systems-thinking is necessary, looking at the complete food supply chain, to understand the impact of changes.
• Creating a vehicle for integrating disparate datasets on soil health collected by private companies and academic institutions.
• supporting more regional and national-scale soil surveillance programmes and on-farm experimentation to support innovative approaches to soil management.

Funding

There was a discussion about how Rothamsted Research and the other research institutions received funding for their work. In general, there was a feeling of uncertainty about how future funding would be structured given the need for longer-term strategic investment in research to support soil health. There was also discussion about how the ongoing political dispute over UK access to Horizon Europe funding was discouraging collaboration with European research centers. More integration between UK-level Government Departments and the devolved administrations would be useful.

June 2023