A summary of the first Webinar in Hope Farm’s Technical Webinar Series 2022/2023, by Helen Mason, RSPB’s Investigations Intelligence Manager (on sabbatical at Hope Farm).

Hope Farm Webinar 1 series 2022/2023 - Farming for resilience and a positive environmental footprint

Here we are again for more fascinating insights through our technical webinar series! You may have previously seen Hope Farm’s 20th Anniversary webinar posts in 2021 and it doesn’t stop there, as there were three new webinars in the series for 2022/2023.

If you are new to our technical webinars, we involve scientists, conservationists and farmers to uncover and share valuable insights and research on topics important to farming now and in the future. It’s easy to catch up on any of the webinars - recordings are available online, or you can read about them here.

Dunnock at Hope Farm. Image (c) Kevin Pigney

The first of the three webinars focused on ‘Farming for resilience and a positive environmental footprint,’ with speakers including:

  • Professor John Starkey, Rothamsted Research
  • Dr Sam Cook, Rothamsted Research
  • Georgie Bray, RSPB Hope Farm manager

RSPB’s Senior Conservation Scientist working on carbon and soils research, Rob Field, introduced the webinar. Rob explained that post-war productivity gains of UK agriculture have been accompanied by a number of negative unintended consequences for the environment including dramatic declines of farmland biodiversity and pollution of watercourses. At the same time in recent years, yields have plateaued, with an increasing gap between the potential of new crop cultivars and the yields actually achieved in farmers’ fields. This might partly be a consequence of degraded natural environment and the ecosystem services it provides to agriculture including pollination and the regulation of crop pests.

Rob then introduced the ASSIST programme (a five-year research program collaboration between Centre of Ecology and Hydrology, Rothamsted Research and the British Geological Survey) and how the programme has attempted to quantify the potential of these services and their providers to improve the resilience of yields in the context of other constraints on productivity including things like abiotic stress particularly climate change.

Hope Farm has first-hand experience of this, having participated in the ASSIST project relating to improving food production efficiency and remaining resilient, whilst reducing our negative environmental footprint in farming.

Prof. John Stalkey - Some thoughts on Regenerative Agriculture

Our first speaker professor was John Stalkey, an agroecologist with Rothamsted. John has a background in weed science and is now responsible for a range of projects including ASSIST, all aiming to better integrate nature and nature-based solutions into commercial production systems.

To lead into the discussion around the need for regenerative agriculture, John began with the history of Rothamsted. Rothamsted was founded as an agricultural research station in 1843 by Victorian scientist Sir John Bennett, a contemporary of Charles Darwin, along with his colleague Sir Joseph Henry Gilbert. They set up a series of experiments called “Broadbalk” measuring the impact of fertilisers on crop yields, which amazingly can still be seen at Rothamsted today. [Ed – this is apparently the World’s longest running farm study - from 1843 to date!]. Broadbalk summarises how we got to where we are now in terms of modern crop production systems, and importantly illustrates why we may need to change our approach …

The Broadbalk experiments look at the effect of different organic and inorganic fertilisers on soil fertility, along with the nutrients required to improve yields in strips of wheat, each 300m long x 6m wide.

To test the combinations, strips received organic fertilisers, inorganic fertilisers, both, or no fertiliser. Over the years, modifications have been made to the experiments including splitting out the strips to control weeds so that parts of the field could be fallowed every five years; using sections to look at other treatments such as rotation and the effect of pesticides; evolving away from cropping winter wheat (as would have occurred in the 1800’s) to align with innovations in crop husbandry and agronomy to mirror industry.

Effectively the experiment has become a yard stick for monitoring and charging the impact of changes in crop husbandry and yield, as demonstrated by the classic yield graph – Figure 1.

Figure 1. The Broadbalk experiment history of crop yields: blue line (bottom), no fertilizer; pink and purple lines (middle), optimum inorganic fertilizer or farmyard manure plus extra inorganic N; orange and green dotted lines (top), wheat following a break crop. Blue box [1] indicates impact of the Green Revolution and blue box [2] the Yield plateau. Winter wheat cultivar introductions are noted on the horizontal axis.

The data shows how the various methods compare against a UK average of around eight or nine tons per hectare and the dramatic impact of crop breeding and cultivar improvements on yields, which tripled during the Green Revolution [See Fig1 Box 1, and cultivars on horizontal axis]. This saw the first dwarfed or short-strawed varieties with dramatically higher harvest index in yield, and importantly, the increase in yield potential was only realised when combined with inputs of inorganic fertilizer and pesticides. John explains that the next striking point is the ‘Yield Plateau’ [Fig 1 Box 2] observed since about the early 2000’s where we’re not seeing the incremental increases in yield.

This indicates there might be an issue with the current cropping system that we’re pursuing: we’ve become locked into simplified systems with high inputs because that’s what modern crop varieties have been bred for. John asks, “Does the yield plateau suggest that we might need alternative approaches…?” then suggests a few reasons for regenerative approaches:

  1. There is a limit to how much we can improve crops. A lot of yield has been improved by changing plant architecture (shortening straw) but we already have very short crops now focussing on bulky grain
  2. We’re losing the crop protection battle in terms of pests, weeds, and diseases evolving resistance to chemical pesticides. Blackgrass is a very good example with increasingly high impacts on gross profit due to the evolution of this weed to be resistant to so many herbicides now;
  3. Increasing input prices mean we are locked into high input systems, that require high levels of production to draw a profit – often with unintended negative impacts on biodiversity; Mapping Farmland Bird declines against UK winter wheat yields illustrate the increase in the green revolution almost directly mirrors the decline in farmland birds (including the plateau).
  4. Declining soil health, which has been monitored by using soil carbon as a proxy (see fig. 2). For arable land use, 38% of soils were in poor condition.

Figure 2. Graphs indicating the soil health in different land uses across the UK. Those soils sitting in orange zone are in good condition, whilst soils in the purple zone are degraded. Samples are taken from a national database of soils in different land uses.

With those above points, John illustrated a few issues with intensive industrialised farming systems that needed addressing not just for the externalities but also for the threats they are to the sustainable production of crops in those systems and that's what's behind a number of calls for alternative approaches to agriculture or more sustainable approaches to cropping systems.

Whilst regenerative agriculture is in trend at the moment as a potential solution, John also outlined a definition from the literature to help identify what was referred to in the rest of the webinar:

“Regenerative agriculture is an alternative means of producing food that, its advocates claim, may have lower-or even net positive-environmental and/or social impacts”

John went on to explain how we can think about regenerative agriculture, a collection of ingredients to fit the above definition. That may be reduced tillage, increased green cover, addition of organic matter, livestock, crop diversity and habitat creation. Whilst regenerative practices have been termed as Integrated Pest Management, Ecological Intensification just to name a few, the ingredients remains relatively consistent. It is this collection of practices that are being scrutinised under the ASSIST project.

The ASSIST project was then introduced in its broadest sense. The philosophy was to try and provide an evidence-base for regenerative agriculture. These were the main parts to the project outlined:

  1. Quantifying the potential contribution of biodiversity and natural capital on farm to food production systems; 
  2. Finding ways to mitigate the impact of crop husbandry and crop production on ecosystem services and natural capital to have a better balanced and functioning ecosystem.

With that, Rob introduced the next speaker – Dr Sam Cook.

Dr Sam Cook – The ASSIST Farm Network: testing sustainable intensification within real arable systems

Sam began by outlining the conflict between food production and nature-based capital, with high input farming feeding the world but causing some problems environmentally on one hand, and organic agriculture really looking after the environment but not really producing so much food in comparison. A resolution of the conflict could be achieved with maintenance of conventional systems whilst reducing the environmental impact or in organic systems increasing yields without further increasing negative environmental impacts. This is what ASSIST has tried to quantify – the benefit of sustainable management practices that enhance ecosystem service processes vital for supporting crop production.

After discussing potential designs with farmers, three main methods were tested in the experiment:

  • sown field margins to support biodiversity beneficial to crop production (pollinators and natural enemies off crop pests – eat the pest and provide free pest control);
  • growing cover crops to increase biodiversity and improve soil structure;
  • adding organic matter which again helps soil structure and enhances the soil functions.

Getting biodiversity into the crop was one of the focusses of the trial. Field margins are known to support biodiversity, but evidence also shows insects struggle to move far out in to the fields. For example, you see half the number of ladybirds 50m into the crop compared to 10m from the field margin. Bees also see a similar decrease from the field edge. This is why in-field strips were planted.

Flowering species were chosen to benefit what we thought would attract specific groups of bees for pollination, parasitic wasps which lay their eggs inside aphids and pest prey and killed them and other predators that come in like hoverflies and ladybirds that eat the pest insects. We also included tussocky grasses to benefit the predatory ground beetles and spiders that take the prey as they drop to the ground, or climb up the crop foliage and take the pests from the crop plants.

Sam outlined the way the system was monitored – across 18 farms based mainly in South East England. The same design was implemented across all farms (fig. 3). Sampling this was done on a spatial grid, based on the 96 metre distance of the infield strips (fitting with tractors and boom lengths). Sample points were along the transects at 12m, 24m, 48m, and 96m from the crop edge, giving 24 total sampling points. This was done to quantify the background levels of biodiversity what's there in terms of insects in total include the key service providing taxa so these butterflies, natural enemies, with a focus on service delivery linked to impacts on yield, not just proxies.

Figure 3. Experimental design of the ASSIST trial. T1 was designed with no additions, T2 to support ecosystem services at either end of the field, and T3 to support ecosystem service delivery in the middle of the field.

Things investigated during the experiment included:

  • insect interactions on different flowers
  • slug/snail counts
  • weeds (blackgrass) percentage cover
  • pests (aphids, parasitised aphids, cereal leaf beetle)
  • natural enemies (hoverfly larvae, spiders, ladybirds, lacewing eggs)
  • prey activity (artificial slugs / caterpillars to identify bite marks, sentinel prey aphids)
  • pollinators
  • soil health (earthworms)
  • yield (hand harvested)

In-field margin establishment: good for grasses like crested dogstail and red fescues, but less so for the tall fescues. Flowering plants like yarrow, common knapweed, oxeye daisies and clovers did well, whereas field scabious, fleabane, and tufted vetch didn't really do well in in any of the sites.

In-field margin ecosystem delivery: from creating complex food webs, representing interactions between insects and different plants, they found hoverflies and some parasitoid wasps really liked the oxeye daisies and wild carrot, whilst bumblebees really liked knapweed.

Pest predation: more aphids were predated when placed on soil surfaces than plants, showing importance of ground predators for controlling pests. There were also more aphids predated upon under T3 (in field wildflower treatment).

Earthworms: more worms in T3 compared to the control

Yield: concentrating on the cereals and rape crops, the differential between treatments increased as the trial progressed. This indicated, that in these crops, sustainable management systems are having a positive effect on yield, with T3 on average being best.

Now work continues to see what barriers there are to the uptake of these kind of systems, with really good indicators of the positive effects these practices may have in cropping systems.

After that fascinating talk, Rob introduced Georgie Bray (Hope Farm Manager).

Georgie Bray - Practicalities of delivering for nature, for ecosystem services on farm

Georgie began by introducing Hope Farm, and the reasoning for purchasing the 181ha site in south Cambridgeshire – to show that wildlife can thrive on a profitable arable farm. This demonstration element is achieved with years-worth of monitoring and implementing of regenerative and integrated pest management practices. This is underpinned by the Farm Wildlife key actions.

On talking through the key actions, Georgie touched on the need to look at existing habitats on farm, as hot spots for wildlife that can be connected across the farm. This could be done using field boundaries to start, looking at flower-rich habitats for example. Winter bird seed mixes are farmland bird focused, but provide an essential life-line for seed-eating birds. Ponds too have been dug out to improve water-holding capacity which in turn provide a life-jacket for lots of species on farm. 

Georgie went on to discuss some of the ways that managing these habitats is planned across the farm to give them the best chance of delivering for nature, as intended, and in turn make best use of public money that funds the habitat management. Some win-wins included picking nutrient poor soils if the soil varies on the farm, perhaps at the top of the hill where the sunlight gets there, but the nutrients may be lost due to runoff to the lower parts of a slope. This would be an excellent place to plant wildflowers that thrive in nutrient poor soils. Connecting habitats is important, to make nature able to access the whole farm, rather than just a convenient corner, so that nature can in turn deliver those ecosystem benefits.

When thinking about what to plant, Georgie outlined a need to see what mix is best suited for a given area. Sam had already outlined some key plants that are better for certain species. Also thinking about native cultivars rather than non-natives that might be less beneficial for our native beneficial invertebrates. Thinking about ensuring delivery for pollinators across the whole season, means thinking about when species are flowering throughout the year. The beginning and particularly end of flowering season can be tricky times for pollinators to find food. Ensuring you have flowers in early March (blackthorn) right through to late September and beyond (bird's foot trefoil, flowering species in winter seed mixes, ivy) soon makes you think about areas beyond wildflower strips that may provide valuable pollinator resources.

Once you have areas and mixes planned, Georgie talked about the need to take your time to ensure good establishment of these habitats. The seed is often expensive, and with the mixtures you plant there are few or no options for herbicide control in most conservation habitats. Taking the time to get a good seedbed, ensuring enough time to control any weeds pre-sowing, and then waiting for the right weather conditions is critical. Speaking to the seed-merchant you are buying from is often a good way of checking on the soil temperature requirements and moisture needed for successful establishment. Check these before going ahead as they are quite different and often more temperamental than most cash crops.

After establishment, it was explained that some remedial management may still be required, often with mechanical means of weed control in your flower margins (mowing). All the way through management of habitats, it’s worth keeping sight of what you are trying to deliver, what nature you are trying to boost, and keeping vigilant of risks that may reduce a habitats potential to deliver. For instance, if thistles creep into a margin they are no problem and still deliver pollinator resources to a certain extent if in small numbers. But if they smother a margin, they reduce the diversity of resources you are providing, making it less useful for nature and a big source of problematic weeds across the farm – so best to get on top of before this point! Always be aware of your agreement too, as many of these habitats that can provide ecosystem services on farm are paid through some form of stewardship.

Finally, Georgie spoke about the remaining area on farm – beyond the habitat provision out of cropped area. Regenerative practices in field are a key way of making the whole farm better for nature, alongside many other benefits (soil health improvements and associated benefits). Making these changes that Jonathan spoke about at the beginning of the webinar, slowly and in a stepwise fashion, are a good way of setting the farm on the journey of being more sustainable in the long term. Making all the changes at once is a good way of making mistakes and not always knowing what has caused the problem. If you set out a longer term plan for slowly introducing new methods into the system though, it makes the whole journey a less stressful one!

To finish the webinar before opening up to questions, Georgie highlighted some useful sources of information that are often referred to whilst trying to make management decisions on farm. Links to those and where to find more information about the work we’re up to are found below:

Farm Wildlife

Nature Friendly Farming Network



RSPB Hope Farm

For further information, please contact Georgina Bray: georgina.bray@rspb.org.uk