The four-year study by the UK Centre for Ecology & Hydrology (UKCEH) was carried out alongside Rothamsted Research and explored various agroecological methods and their financial viability across 17 farms in southern England.
It showed that incorporating nature-friendly practices within farming – agroecology – increases biodiversity, pollination by bees, natural pest control and numbers of earthworms.
This boosted crop yield, but the cost of creating the habitats and the loss of some productive land on which to create these habitats affected the profitability of these systems. New subsidies may therefore be required to support farms’ transition to sustainable agriculture.
Trialling agroecological methods
Scientists worked with farmers to co-develop the trials using simple management practices within three different agricultural systems on each of the farms:
1) Business-as-usual – typical intensive agriculture and no nature-friendly farming.
2) An ’enhanced’ ecological farming system which involved planting wildflower field margins to provide habitat for bees, beetles and spiders, and sowing overwinter cover crops to capture carbon and retain nutrients in the soil.
3) A ‘maximised’ ecological system’ which added to the enhanced system by also planting in-field strips of wildflowers – ‘stripey fields’ – to provide ‘runways’ for beneficial insects to get further into crops, and the addition of organic matter in the form of farmyard manure to improve soil health.
Benefits for nature and farmers
The enhanced and maximised ecological systems saw increased populations of earthworms, pollinators such as bees and hoverflies, as well as natural predators of crop pests such as ladybirds, lacewings and spiders. This reduced populations of pest aphids and snails, and increased the seed numbers and thereby yield of flowering crops like oilseed rape.
There was also higher soil carbon and overall increased crop yields on the farmed area due to healthier soils, greater pollination and natural pest control.
The study also found the enhanced ecological system was as profitable as intensive farming, but only due to agri-environmental subsidies.
While the various benefits for biodiversity, soil carbon and yield were greater in the maximised ecological system – which included planting in-field wildflower strips and buying in farmyard manure – the study found that the average farm would require increased subsidies to make it as profitable as intensive farming.
Future-proofing farms
UKCEH ecologist Dr Ben Woodcock, who led the study, published in the Journal of Applied Ecology, explained: “Without the introduction of new financial incentives, many farmers will be deterred from adopting agroecological farming practices and systems. This could leave them locked into high input, intensive farming systems and more exposed to the impacts of pesticide resistance, declining soil health and climate change.
“Agroecological methods are good for biodiversity, food security and, in the long-term, provide more secure farm incomes but habitats can take several years to establish, so agri-environment subsidies are essential to helping farmers transition to these more sustainable systems.”
Demonstrating the effectiveness of agroecological practices to farmers could be a critical step breaking farmers free from ‘intensification traps’, the study authors said.
Professor Jonathan Storkey, an ecologist at Rothamsted Research, said: “This study confirmed that managing land on farms for wildlife is not in direct conflict with food security but can support sustainable production by increasing yields and reducing pest pressure. These ‘ecosystem services’ could potentially substitute for chemical fertilisers and pesticides which negatively impact the environment.
“However, our analysis has shown that realising these benefits will require additional support for farm businesses that currently operate on very narrow profit margins. As input costs increase, however, these agroecological approaches may become more attractive.”
Training and increasing experience will enable farmers to get the most out of measures that support nature like wildflower field margins, for the types of habitats needed to support beneficial insects have very different requirements to crops, the study authors said.
