A summary of the 3rd Webinar in Hope Farm's 20th Anniversary series, by Sophie Mott, RSPB’s Conservation Advisor for Cambridgeshire
Here we are again! If you’ve gotten this far perhaps you’ve seen the previous two webinar posts or indeed the webinars themselves. In case you haven’t, I’ll tell you what it’s all about. Hope farm is celebrating its 20th Anniversary this year, and to celebrate we’ve put together a series of five webinars involving scientists, conservationists and farmers to cover some topics important to farming today and for the future. There are blogs about the available on youtube, the links to which are at the bottom of each blog or can be found on the Farm Wildlife channel. Also, there are still two more webinars to catch! Find the registration links at the end of this blog.
This webinar began with an introduction by the RSPB’s head of Agricultural advice, Richard Winspear. Richard explained the premise of ecological intensification as allowing nature to do the work for you, looking after the wildlife in the soil, crops and field margins to boost natural pest control and pollination. When Hope farm began, its mission was to manage portions of the land for wildlife whilst continuing to manage the rest of the land for crop production. The stark results of this speak for themselves, with 3x as many breeding farmland birds, even more wintering birds, 4x more butterflies, and 19x more bumblebees at hope farm than either when we set a baseline 20 years ago, or when compared to a control farm with the bees. Job done? Well, over the last 5 years Hope farm has moved on to looking at what can be better done with the 90% of land used for crop production still, rather than conservation purposes, including another evolution of our integrated pest management and soil management. The biodiversity supported by the crops is at least as important for nature recovery as the wildlife habitats. Hope farm’s contractor has found that managing the whole system to restore the soil, pollinators and pest control has improved the profitability of his business as well as the biodiversity his farms support.
Sustainable innovations with the ASSIST project – Ben Woodcock
With this, Richard introduced our first speaker Ben Woodcock. Ben is an ecological entomologist with the Centre of Ecology and Hydrology. He researches management solutions to enhance biodiversity and ecological function in arable and grassland farming systems. Ben is also an investigator on the ASSIST, Achieving Sustainable Agricultural Systems, project.
Ben began with an overview of the ASSIST project. Which is a five-year research program collaboration between Centre of Ecology and Hydrology, Rothamsted Research and the British Geological Survey. It is focused on developing innovative farming systems that increase crop productivity and resilience to future threats such as climate change and reducing the environmental and ecological footprint of agriculture. By looking at aspects of high input farming, aspects of low intensity farming and trying to find the middle ground where they can integrate to be the best of both worlds with good productivity and profitability but also thriving biodiversity.
The project was born off the back of a piece of research by CEH at Hillesden farm. This is a 1000ha site that up until the early 2000’s had never been in any agri-environment scheme. The site was split into 15 “farmlets” of about 50-60ha each. Each farmlet was either a;
Originally, this research was targeted at measuring biodiversity but as the farm was able to provide detailed yield mapping, the project extended to include analysis of yield, taking into account land taken out of production. What this analysis revealed is that for the first four years, the yields between the treatments showed little difference and remained below the regional average (the dotted straight line). However, in years five and six, the entry level scheme with 3% land for wildlife and entry level scheme plus with 8% land for wildlife produced yields above the regional average and significantly above the cross-compliance land. In year six, the two schemes also begin to separate with the scheme with 8% of land for wildlife breaking away again and producing yields much higher than the regional average or other two treatments, figure 1.
Figure 1. Graph of yield analysis of the three treatments; cross compliance – black line, ELS with 3% land manage for wildlife – blue line and ELS Extra with 8% land managed for wildlife – red line. The dotted line shows the regional average yields.
Ben mentioned another study demonstrating the importance of the landscape agricultural land is surrounded by. With 10 years of yield data from Defra, it was shown that yield stability and resistance to extreme events like drought or flood, are increased in areas of agricultural land associated with semi-natural habitats. Why is that? The semi-natural habitats are providing ecosystem services such as;
However, a third of pollinator species declined in their range from 1980 to 2013. With similar loses among other taxa. There is a good suggestion that this is a result of a range of different practices. It’s not just the species loss that’s important. Whilst all pollinators; a honeybee, solitary bee and bumblebee spend very different amounts of time on each flower they visit. Each species is functionally unique, and those differences are crucial in understanding how they can deliver these ecosystem services. Looking at national patterns of functional diversity in pollinators, we have deficits in functional diversity in areas of high agricultural production. This pattern isn’t unique to pollinators. Ben also mentioned some research looking at functional groups of predators and their resilience to insecticides. When exposed to sub lethal doses of pyrethroid some species were unaffected and continue to predate on aphids as normal, others had a feeding depression ranging from one to five days in which they struggled to predate aphids. Worryingly, some of the commonest species are the most sensitive to insecticide use, showing these depressions. Having a diverse generalist predator community acts as an insurance policy in maintaining natural pest control following exposure to insecticides, as averaging across all species you are likely to have a few that do not experience the depression. Additionally, a large meta-analysis study has shown that increased yield in OSR and improved predation by generalist predators are directly link to functional diversity of the invertebrate community.
So, in order to get this diversity, we need to build and develop approaches to integrate biodiversity within intensive farming systems. Enhancing beneficial services provided by biodiversity including; pollination, pest control and management of soil and protection of water resources on farms. One of the key problems is that arable agriculture is a destructive system. With each harvest, you get a wiping out of both systems. So, we need to establish non-crop habitats to support populations of beneficial invertebrates. This has been shown to be especially important for pollinators. Since 1930, 76% of key flowering plants have declined in our countryside. Providing field margins and set aside areas provides simple mechanisms to increase key resources for native biodiversity. These habitats are not just for pollinators. A lot of predators also need pollen and nectar in addition to refuge habitats suck as tussock grasses. Parasitic wasps, for example, need a good source of nectar in order to produce the eggs that parasitize pests. A big issue as well is a need to break up big fields. After each harvest, the invertebrates that have sought refuge in the wildlife habitats then need to get back out in the crop. If you’ve got huge fields, there is a real question as to whether they can reach the middle of them. Figure 2 shows you what has been seen in research and is common trend among invertebrates. The further into a crop you go the fewer beneficial invertebrates you find. This isn’t true for every species but is for a good number of them.
Figure 2. The chart on the left shows a decline in abundance of bumblebees the further into the field you go. Similarly the chart on the right shows the abundance of a range of sward active / flying predators at 10m into a field and 50m into a field
So we need to develop innovative approaches to help maintain these populations in field centres. This is part of the big field study in the ASSIST project. The study is comparing cross compliance fields, with no agri-environment improvement to fields with margins and then again to fields with the margins but also with infield strips providing runways to help support and transport these beneficial insects back into field centres, figure 3.
Figure 3. Demonstration of the three field types in the ASSIST trial. One with no enhancement, one with field margins and one with field margins and infield strips. Replicated across several farms.
This study is still ongoing but preliminary results are promising. In rates of parasitism of aphids, figure 4, what we can see is that in the business as usual field with no enhancements, the rates are very low. As we move into the field with margins it gets better and as we go into the final all singing all dancing field, we get significantly higher rates.
Figure 4. Rates of aphid parasitism in the three treatment fields
Plasticine slugs have been used to identify the predation rate of ground beetles on slugs in a crop which follow a similar trend to the aphids parasitism with the infield strips field supporting higher numbers of predation and a reduction in the number of slugs, figure 5.
Figure 5. Rates of predation by ground beetles on slug populations
Earthworm populations are also being monitored and again, seem to be following the same increasing trend with more earthworms in the field margin treatment than the conventional and even more in the infield strips treatment. These things are a really good indication that this final treatment is having direct benefits for lots species.
In summary, in UK agricultural the big increases in crop yields have already been obtained, we can’t realistically aim for too much more, especially in our current intensive, chemical based systems. The solution will depend on; better agronomy, new crop varieties (GM), new agro-chemicals, precision farming and new technology and biodiversity linked ecosystem services. We need to fit biodiversity into the future of agriculture. Biodiversity can provide an additive value to the existing agricultural systems, in terms of yield resilience and pest control. It can take time for these services to increase, it doesn’t happen instantly. You need to create the good habitat and allow populations to increase before it gets better over time. The key idea here is future proofing the agricultural system. If we provide the biodiversity and support those key ecosystems then in the future when you might have increased resistance to pesticides or removal of pesticides, you have the potential to provide a compensatory mechanism to help those management systems and might be not be as reliant on those chemicals anymore anyway.
Practical Ecological farming at Hope farm – Georgie Bray
Next up, Richard introduced Georgie Bray. Georgie is the manager at Hope farm, starting with the RSPB in 2017 as the farms assistant manager. She is a 3rd generation farmer herself, growing up on her arable family farm in North Essex. Georgie has a BSc Zoology degree from the University of Nottingham along with an MSc focusing on bird ecology, nature writing, conservation genetics and conservation agriculture.
Georgie started by talking about the wildflower margins at Hope farm. Hope farm has 6.8ha of wildflower margins (3.2% land), and 3.2ha of pollen and nectar mixes (1.7% land). Georgie explained that is difficult to prove the yield benefits from the invertebrates these habitats support on an everyday farm. Hope farm practices as many of the principles mentioned by Ben and looks at how the whole farm changes as a result. The flower mixes sown on the farm are very diverse to try and support as much wildlife as possible creating a balanced ecosystem that will better enable the farm to tackle and pest and disease issues. These habitats are not just for invertebrates though they are often what we talk about. They support many mammal and bird species also which play their part in the wider ecosystem.
Figure 6. Three wildflower margins on Hope farm drilled at different times of year. All photos taken in May 2020.
In the above photos, figure 6, you can see three wildflower margins. The left-hand photo has very few flowering plants or diversity within the margin and is heavily dominated by grasses. The photo in the middle has lots of flowering plants but is dominated by a singular species so offers little diversity, this can be very common in the first few years of margin establishment. The photo on the right has lots of diversity, a good balance of grasses and flowers and a good number of flowering plants. What is different about the three margins is the effort. The photo on the left was drilled with a cheaper seed mix than the other two, cut twice within its first year and subjected to an annual cut and remove the following autumn. The photo in the middle received the more expensive mix but the same management as the left photo. The photo on the right also received the more expensive mix and additionally more intensive first year management, being cut every few weeks within its first summer and autumn cut and remove thereafter. Georgie then looked at the profit of these margins based on their countryside stewardship incomes. In countryside stewardship all three of these wildflower margins are paid at £539/ha. Averaged over the five years of the agreement, the left margin costs £390 to establish and maintain, a profit of £149. The middle margin costs £500, a profit of £39 and the right margin costs £550, a profit of -£11. The margin on the right was part of a trial so the decision to undertake intensive management was to ensure a good habitat quickly for the trial, it shows that results can be achieved quickly but it is potentially non-profitable to do so under the current scheme. Georgie pointed out that with the right management flower margins get better over time and some of the best flower margins on Hope farm are around 15 years old.
Next Georgie moved on to cultivations, organic matter and legacy effects at Hope farm. Autumn 2019 was a tricky drilling year for winter crops as it was exceptionally wet. Winter wheat is the most profitable crop for Hope farm and was planned to be drilled in 80ha across the farm. Due to the weather, only 5ha were drilled. The 5ha was one small field. This field is consistently well performing, it’s reliable to travel on and has been able to be direct drilled for the last four years as the soil is healthy and resilient. Unlike the rest of the farm which has been in agricultural production for much longer, this field was only converted to arable land 40 years ago, previously it had been long term grassland. Perhaps there is something to consider there.
Figure 7. An NDVI map showing biomass in a crop of OSR in a field split into quarters of different treatments
This leads nicely into the farm is looking at cover crops and compost and how they may impact soil health and biodiversity. For the biodiversity you’re best off checking last month’s blog or webinar for more information about the trial and results. Looking at one field in the trial growing oilseed rape, a crop getting harder to grow each year, you can see the treatments in different quarters of the field; control, compost only, cover crop only, both compost and cover crop on this NDVI map showing the biomass in the field taken in May of the harvest year, figure 7. This field had flea beetle and pigeon pressure quite uniformly. No insecticides were used but you can see the differences in crop growth. The control quarter was near crop failure, harvesting 0.5 t/ha. The cover crop quarters were harvesting 4.5 t/ha in the very dark green spots and the compost and other green areas were harvesting between 2.5-3 t/ ha which is a profitable crop.
Figure 8. An NDVI map showing biomass in a crop of winter wheat in spring of 2019 in a field that was previously two fields under different management.
Good soil management is showing some obvious benefits there but what about the legacy effects? Does it matter long term? The short answer is yes. This can be seen in one field in particular at Hope farm. 2018 was a tricky year for spring crops like the wheat that was in this field, figure 8, as we entered a drought early in the spring. Regardless of that what you can see is the exact line where a hedgerow used to be separating this field into two. The left-hand side, in red, has been in an arable rotation for over 100 years. The right-hand side was long term grassland until 40 years ago. There is something very different about each side of the old hedgerow in terms of crop establishment and growth. 40 years on and the effects of the previous low intensity grassland soil is still positively impacting crop growth today.
Hope farm regularly adds organic matter back to its fields. Organic matter is said to improve structure, above and below ground diversity, and macro and micro nutrients. Has this been the case at Hope farm? Yes. Hope farm has seen changes in nutrient levels of;
The soil structure is visually better, and the land is more resilient to travelling. The biodiversity is improving across all taxa. As well as organic matter increases of up to 2% in soil in five years. Sounds wonderful on all fronts, but it does come at a cost. Cover crops cost around £30/ha, compost (use at 30 t/ ha), costs around £375 /ha, chicken manure (used at 10t /ha, costs around £125 / ha and results are not immediate. A large component of these costs is transport so if you are able to use a local source or are in a mixed farming system, these costs may be greatly reduced. Additionally, once the changes begin to happen there are all the benefits previously spoken about along with cost savings on other inputs needed such as fertilisers and pesticides and increase yields as we saw with the OSR, 0.5 t/ha and 4.5 t/ha is quite a different gross margin.
In summary, the Hope farm experience shows that high inputs early on pay dividends for habitat creation for wildlife, as we saw with the flower margins, and for soil management and crops as we’ve seen from the NDVI maps. Adding organic matter has got high short-term costs but good long term pay offs. Looking at the legacy effects from the two pasture fields converted to arable land, the benefits are still visible 40 + years later in terms of soil resilience and crop growth. Managing for the long term is difficult, especially with the uncertainty in the current economic climate but it is important to start to make steps towards these changes as soon as possible to ensure a longer term financial and ecological stability.
If you’d like to watch the previous webinars there can be found on youtube here;