Towards guidance for the design and placement of vegetated filter strips

A combined field, laboratory and modelling approach to the study of vegetated filter strips (VFSs) was carried out in order to provide guidance on optimum design and placement for trapping sediment from overland flow. Monitoring of fifteen established filter strips in the Parrett Catchment, England, informed on the complexity of intercepting flow pathways to optimise filter strip performance. Results suggest that a 6 m VFS will trap an average of 1.74 t year -1 of material from a field of 1 ha, but this is highly variable depending on design, placement and management factors. In most cases the majority of coarse sediment is trapped at the upslope edge of the VFS and is typically >85% sand. A revised Morgan-Morgan-Finney model was tested against a range of field and laboratory datasets and an efficiency coefficient of 0.7 was achieved. When testing the model against the field results from the Parrett Catchment, an active filter strip area was used. This took into account only the area of the filter strip effective in trapping sediment due to the convergence and bypassing of flow pathways. In the field, filter strip performance will be improved by reducing concentrated flow reaching the strip and ensuring that flow does not bypass the strip through burrows and gateways, using in field erosion control, maintaining level ground between the field and filter strip edge and managing the strip to maximise the density of vegetative material, particularly the number of vegetative stems. Potential applications for the research include a field based Decision Support System, design of filter strip biophysical architecture and catchment planning.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Multiple ecosystem services from field margin vegetation for ecological sustainability in agriculture: scientific evidence and knowledge gaps

Background: Field margin and non-crop vegetation in agricultural systems are potential ecosystem services providers because they offer semi-natural habitats for both below and above ground animal groups such as soil organisms, small mammals, birds and arthropods that are service supplying units. They are considered as a target area for enhancing farm biodiversity. Methodology: To explore the multiple potential benefits of these semi-natural habitats and to identify research trends and knowledge gaps globally, a review was carried out following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A total of 235 publications from the year 2000 to 2016 in the Scopus and Web of Science databases were reviewed. Results: The literature showed an increasing trend in the number of published articles over time with European studies leading in the proportion of studies conducted, followed by North America, Asia, South America, Africa and Australia. Several functional groups of organisms were studied from field margin and non-crop vegetation around agricultural lands including natural enemies (37%), insect pests (22%), birds (17%), pollinators (16%), soil macro fauna (4%) and small mammals (4%). Ecosystem services derived from the field margin included natural pest regulation, pollination, nutrient cycling and reduced offsite erosion. Some field margin plants were reported to host detrimental crop pests, a major ecosystem dis-service, potentially leading to increased pest infestation in the field. Conclusion: The majority of studies revealed the importance of field margin and non-crop vegetation around arable fields in enhancing ecosystem biodiversity. Promotion of field margin plants that selectively enhance the population of beneficial organisms would support sustainable food security rather than simply boosting plant diversity. Our analyses also highlight that agro-ecological studies remain largely overlooked in some regions

Towards guidance for the design and placement of vegetated filter strips

A combined field, laboratory and modelling approach to the study of vegetated filter strips (VFSs) was carried out in order to provide guidance on optimum design and placement for trapping sediment from overland flow. Monitoring of fifteen established filter strips in the Parrett Catchment, England, informed on the complexity of intercepting flow pathways to optimise filter strip performance. Results suggest that a 6 m VFS will trap an average of 1.74 t year -1 of material from a field of 1 ha, but this is highly variable depending on design, placement and management factors. In most cases the majority of coarse sediment is trapped at the upslope edge of the VFS and is typically >85% sand. A revised Morgan-Morgan-Finney model was tested against a range of field and laboratory datasets and an efficiency coefficient of 0.7 was achieved. When testing the model against the field results from the Parrett Catchment, an active filter strip area was used. This took into account only the area of the filter strip effective in trapping sediment due to the convergence and bypassing of flow pathways. In the field, filter strip performance will be improved by reducing concentrated flow reaching the strip and ensuring that flow does not bypass the strip through burrows and gateways, using in field erosion control, maintaining level ground between the field and filter strip edge and managing the strip to maximise the density of vegetative material, particularly the number of vegetative stems. Potential applications for the research include a field based Decision Support System, design of filter strip biophysical architecture and catchment planning