Securing long-term ecosystem function in lowland organic soils (SEFLOS)

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The UK produces 58% of its own vegetables which have an estimated economic value of £1.2 billion annually. Many of these are produced on the lowland fen peatlands within the East Anglia region. This is particularly the case for field-grown salad vegetables with these peatlands supplying the majority of salad vegetables to all the major UK supermarkets. While these soils are recognised as being super-productive, they are also highly susceptible to damage which is threatening their long term economic future. For example, the average rate of soil loss from a combination of wind erosion and microbial breakdown of the peat lies in the region 1-2 cm depth per year. It is also widely predicted that the rate of loss is likely to increase with climate change making it a fragile resource. Some of the more shallow peats have already been completely lost, while the deeper peats have a finite lifetime estimated to be in the region of 75-125 years unless something is done to reduce the rate of soil loss. The recent House of Commons Environmental Audit Committee report on Soil Health identified the loss of soil from cultivated peatlands as one of the greatest threats to soil security in the UK. In response to this, our project aims to work with the horticultural industry and other key organisations to investigate new ways to save these peatlands from further rapid degradation and a loss of natural capital. We will focus on trying to reduce both the biologically-mediated loss of soil carbon and also the physical wind erosional loss of soil. We hypothesise that active management of the water table at strategic times of the year (e.g. during winter when there is no crop in the ground) can be used to reduce microbial activity in the soil and reduce losses of peat in the form of CO2. However, this must be done in such a way that it doesn't increase the release of other greenhouse gases (CH4, N2O) or result in other negative impacts on productivity or on soil quality. In addition, using outdoor mesocosm trials, we will explore other potential synergistic strategies that may complement water table intervention as a soil conservation measure (e.g. use of nitrification inhibitors, cover crops etc). As our knowledge of the amount of soil lost by wind erosion remains poor, we will also use field monitoring and controlled wind tunnel experiments to get a better quantitative estimate of this loss pathway. This will allow growers to decide on whether to invest in protective technologies that might reduce erosional losses (e.g. soil physical binding agents, winter cover). While this project will generate lots of fundamental knowledge on peatland behaviour under different management scenarios, it is important that the research also recognises the socioeconomic context in which these agricultural systems operate. A key part of this project will therefore be to evaluate the social, economic and environmental impacts of the alternative strategies and compare these against the business-as-usual scenario. To facilitate this, a stakeholder workshop at the start of the project with representatives from industry, environmental regulators and policymakers, local drainage boards and conservation bodies will be used to actively steer the project towards outcomes that are both practical, economically viable and provide the best environmental outcome. This will be complemented by a final engagement workshop towards the end of the project where the barriers to technology adoption are explored. This will lead to the production of a grower- and policy-orientated roadmap for future preservation of this fragile soil resource and will have a focus on balancing economic and environmental sustainability. Ultimately, the research simultaneously aims to protect this soil resource for generations to come whilst maintaining profitability, productivity, and UK government's desire for sustainable intensification, greater food security and reduced greenhouse gas emissions.