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The Greening measures in the Common Agricultural Policy require that ecological focus areas (EFAs) comprise 5% of eligible hectares on arable farms (where arable land exceeds 15ha). The objective is to safeguard and improve biodiversity on farms.
Farmland habitats (including eligible and non-eligible EFAs) can support an abundant, diverse community of species, which in turn play an important role in the delivery of essential ecosystem services. These services support production, nutrient cycling, flood regulation, climate regulation, aesthetic value and biological control of pests. Therefore, conserving and enhancing biodiversity is vital to sustainable production agricultural systems.
Sustainable production approaches are particularly important for tillage productions systems. For example, pest management in cereals is becoming increasingly challenging due to loss of active ingredients in the reregistration process and the development of insecticide resistance.
This has resulted in a lack of effective management options and the urgent need to develop more sustainable integrated control options. Increasing biodiversity can enhance the contribution of natural enemies to pest control.
Maintaining and enhancing farmland habitats will thus support beneficial species, such as natural predators of pest species, while also supporting many pollinator species and playing a role in reducing soil erosion and improving water quality.
Ongoing work at Teagasc, in conjunction with the University of Edinburgh and the Scotland’s Rural College (SRUC), will assess the effectiveness of EFAs to enhance ecosystem services such as pest management.
EFAs include landscape features such as hedgerows, drains, fallow land, buffer strips and margins that act as biodiversity hotspots in agricultural landscapes.
Arable field margins are herbaceous strips or blocks around arable fields that are managed to provide benefits for wildlife or to reduce water and soil run-off into watercourses.
Arable field margins include cultivated low-input margins, margins sown to provide seed for wild birds, margins sown with wild flowers or agricultural legumes and managed to provide pollen and nectar resources for pollinators and other beneficial insects and margins providing permanent grass strips with mixtures of tussocky and fine-leaved grasses.
As an area of non-cropped habitat, field margins may provide multiple benefits for biodiversity. To date, 276 tillage farmers in GLAS have sown 368km of arable grass margins. Field margins are used for foraging, nesting, feeding, as shelter or for migration and movement by various species.
Agronomic benefits
As a suitable habitat for insects, field margins also have the potential to provide additional agronomic benefits for the adjacent crop by providing ecosystem services in the form of pollination or pest control through promotion of natural enemies.
For cereal aphids, the major pest of cereal crops in Ireland, specific and general natural enemies include parasitic wasps, hoverflies, lacewings, ladybirds, ground beetles, soldier beetles, rove beetles and spiders.
Non-crop habitats may maintain populations of alternative hosts and prey for the parasitoids and predators of crop pests. This enhances natural pest control by providing the natural enemies of pests with alternative hosts and prey during periods in which host and prey density is low in fields or by increasing the fitness of natural enemies.
Wildlife habitats also act as sources of pollen and nectar, which are essential for many species. More diverse vegetation, including flowering weeds, for example, results in a greater availability of pollen and nectar, which may support higher densities of carabid beetles, syrphid flies and parasitoids. Field margins are also highlighted as one way farmers can support bees and other pollinators as a source of flowering plants for pollen and nectar, as well as grass tussocks for nesting sites.
Although the positive role of non-cultivated habitats for natural enemies, such as invertebrate predators and parasitoids, has been highlighted, relatively little is known about their role in the management of pests and their contribution to crop yields.
Teagasc research aims to identify the impact of various different EFAs on the effective delivery of ecosystem services contributing to the management of pests and to crop yield. EFAs, including arable margins, potentially have an application in an integrated pest management approach which combines cultural, physical, biological and chemical control options to achieve sustainable pest control. An experimental arable margin trialling a range of seed mixtures will be on display during the Crops & Cultivation open day.
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