Legacy effects of extreme flood events on soil quality and ecosystem functioning

Lead Research Organisation: Bangor University
Department Name: Sch of Environment and Natural Resources

Abstract

The UK and many areas of Europe have witnessed unprecedented flooding this winter. Severe long-term flooding of agricultural land can have disastrous impacts on ecosystem functioning as well as having severe consequences on the economic and social wellbeing of rural communities. The persistence and magnitude of floodwaters in parts of the UK (e.g. Somerset Levels) provide a unique opportunity to investigate the impacts of long-term floodwater inundation on soil health and ecosystem service delivery. The aim of this 'Urgency' project is to: (1) provide vital information on the negative effects of recent flood events on soil functioning, (2) identify potential tipping points in terms of inundation time, (3) quantify rates of ecosystem function recovery and any potentially irreversible effects, (4) identify potential future intervention measures to promote ecosystem recovery, (5) provide stakeholders (e.g. landowners, Defra, NFU, EA) with critical scientific information to be able to make informed decisions (i.e. to minimize immediate impacts such as production losses) and respond and adapt to potential future flood events.

Planned Impact

The research area and associated aims of this NERC Urgency project are of international relevance, highly topical and central to the delivery of the new NERC science strategy. The work is also integrally aligned with needs of Defra who are co-funding the more applied aspects of this proposal.
Impact in the user community will be realised through the development of KE partnerships with those involved in policy and operational management of the environment. To this end, we have already held a suite of meetings and discussion sessions with a wide range of stakeholders prior to finalising our proposal, in order to ensure that their interests and concerns are properly represented in our NERC Urgency project, and that the science we propose is transferable and useful beyond the immediate academic beneficiaries.

Defra are co-funding this proposal (£60K) thereby demonstrating their clear commitment to the project in terms of supporting the science and dissemination elements which will greatly contribute to the project's impact. Six other stakeholder organisations have provisionally agreed to help co-ordinate the field sampling, provide access to data and facilitate dissemination events. All will be invited to attend the final dissemination workshop. These include Government organisations (Environment Agency, Natural Resources Wales), landowner organizations (National Farmers Union, Farmers Union of Wales) and agricultural industry representatives (Hybu Cig Cymru, EBLEX).
We will deliver KE through a 5 step process:

1. All the Academic Project Partners and Defra in particular have participated in the final formulation of this bid, providing valuable suggestions to hone the programme to ensure that anticipated outcomes meet their interests and operational needs;

2. We will develop links with the wider stakeholder community through the project website and existing KT networks in which we are already involved, and will ensure wider public engagement through Universit Science Days and local and national media;

3. We will produce three factsheets on specific policy implications of our research findings for our stakeholder organisations, making these publicly available through our project website and the publicity activities of our stakeholder organisations;

4. We will engage with the wider academic community through: (i) providing access for external researchers to our data; (ii) publication of 3 papers in international peer reviewed journals; (iii) feedback on our findings to the national and international policy arena through Defra and our participation as expert members of the IPCC, WG LUCCG etc, (iv) presentation of our findings at conferences, and (iv) a contribution to Planet Earth;

5. We will host an end-of-programme interactive workshop on 'Soil Responses to Long-Term Flood Inundation' targeted specifically at the wider stakeholder community. This will report on the current state-of-knowledge, implications for future land use management, implications for future land use policy, potential mitigation measures to reduce the impact of flooding, and identify priority areas for future research and potential avenues for funding.
 
Description Worked with farmers to develop new flood resilience strategies.
Found that existing interventions used by farmers to recover from flood do not work and that new strategies are needed.

Executive summary
This study explored the effects of prolonged flooding on soil microbial, chemical and physical properties through regular sampling of fields on five commercial farms for 9 months following the 2013/2014 winter floods, and through controlled laboratory experiments. The effect of using equipment to alleviate compaction and poor soil condition of flooded soils was also determined on two commercial farms. Finally, a survey was conducted with the aim of determining farmers' perceptions of the relative threat of flooding to their businesses compared with other potential threats, and to assess what adaptation strategies have been used on farms that have been flooded, and what management strategies have been tried to alleviate flood affected soils. The online survey had to be adapted to a face-to-face survey at a large agricultural show, due to farmer survey fatigue in the flooded area.
Monthly sampling of flooded fields on the commercial farms provided evidence that: earthworm numbers were reduced by flooding but number recovered within 3-9 months of the flood water receding; the electrical conductivity of soil remained higher in flooded fields for the majority of the monitoring period; agricultural crop biomass was severely affected by flooding, with crops such as swedes and spring onions being completely destroyed, resulting in farmers re-cultivating and planting new crops. During the sampling visits we noted that recently sown pastures were not as flood resilient as permanent grassland swards.
The laboratory studies demonstrated that during flooding organic N is mineralised to ammonium which accumulates in the soil until flood water recedes. However, in one experiment we measured increased ammonia emissions during the flood period under warmer temperatures. Soil nitrate concentrations reduce during the flooding period. However, once the flood water has receded then ammonium is nitrified to nitrate, and nitrous oxide is emitted. In contrast, methane is emitted from flooded soil when organic matter is present particularly under warmer temperatures, but following flood water removal the soil becomes more aerated and methane emissions cease, as greater CO2 fluxes are observed. These findings suggest that flooding is likely to increase the emissions of greenhouse gases and ammonia from agricultural land, but this needs to be verified in the field, e.g. via exploration of atmospheric concentration data for GHG emissions and ammonia from tall towers during recent flood events.
There was no consistent effect of slot seeding or use of a sward lifter or soil aerator on soil properties or pasture yields on the commercial farm large-plot experiments.
The farmer survey resulted in 50 completed questionnaires. Respondents considered flooding to pose the lowest threat to farm businesses compared to other threats, e.g. severe frost and snow, and a reduction in farm subsidies (which also scored high in terms of a threat that farmers felt they had least control over). However, those farmers who had experienced extreme flooding gave significantly higher scores for the degree of threat that flooding poses to their businesses, and significantly lower scores for degree of control.
Exploitation Route Working with DEFRA to bring in new guidance.
Working with Welsh Government on new agri-environment measures.
Sectors Agriculture, Food and Drink
URL http://agrisoils.bangor.ac.uk/index.php.en
 
Description Used by Natural England in official report. Helped Welsh Government who subsequently funded a National Research Network in this area. Completed Defra report part-funded by the project: http://sciencesearch.defra.gov.uk/Default.aspx?Menu=Menu&Module=More&Location=None&Completed=0?ojectID=19462
First Year Of Impact 2015
Sector Agriculture, Food and Drink,Environment
Impact Types Economic,Policy & public services
 
Description COFUND
Amount £326,230 (GBP)
Funding ID Jinyang Wang 
Organisation European Commission 
Sector Public
Country European Union (EU)
Start 02/2016 
End 01/2019
 
Description NRN Ser Cymru
Amount £473,291 (GBP)
Funding ID NRN5 
Organisation Welsh Assembly 
Sector Public
Country United Kingdom of Great Britain & Northern Ireland (UK)
Start 11/2015 
End 10/2018
 
Description Conference talk 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Postgraduate students
Results and Impact talk at ETH Switzerland
Year(s) Of Engagement Activity 2016
 
Description Conference talk 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Postgraduate students
Results and Impact BSSS annual meeting in Wales
Year(s) Of Engagement Activity 2016
 
Description Conference talk 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Postgraduate students
Results and Impact Talk on flooding by Antionio Rodriguez
Year(s) Of Engagement Activity 2016
 
Description Farmer working group 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact Expert panel at Royal Welsh Show
Year(s) Of Engagement Activity 2016
 
Description Talk at John Innes 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Postgraduate students
Results and Impact Conference talk on flooding by DL Jones
Year(s) Of Engagement Activity 2016
 
Description defra debrief meeting 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Policymakers/politicians
Results and Impact Policy meeting with defra on project results
Year(s) Of Engagement Activity 2015