Case study: Reversion of arable land to lowland chalk grassland

Author: Lynne Roberts:  The RSPB’s Manor Farm, Newton Tony, Wiltshire

Aims and setting

Chalk grassland is one of the richest landscapes for wildlife in the UK and is a habitat which has suffered significant losses in past decades. This case study focuses on Manor Farm in Wiltshire, now the operational base of RSPB’s Winterbourne Downs nature reserve, which was acquired by the RSPB in 2005 with the overall objective of creating a habitat 'stepping-stone' for wildlife between two internationally important chalk grassland areas: Salisbury Plain and Porton Down.

To enable wildlife species to thrive on the farm and expand their range from the neighbouring chalk grassland areas, much of the arable farmland was reverted to lowland calcareous grassland, a UK priority Biodiversity Action Plan (BAP) habitat. An initial reversion of about 40ha in 2006 has been followed by further grassland creation projects at the rate of around 25ha per year, and now almost 200ha of the total farm area of 296ha has been reverted to semi-natural chalk grassland.

Agri-environmental scheme grants from Natural England and capital grants from the Heritage Lottery Fund were major contributors to the reversion works.
This case study describes in detail the reversion of a 24ha area of arable land, started in 2008.

Site preparation and sowing

In order to select the most conducive sites for reversion, soil samples from across the farm were analysed. It is recognised that land with low nutrient levels, particularly available phosphorous, is the most suitable for creating and restoring species-rich grassland - the best sites will have a phosphate index of between 0 and 1. The results of this showed much of the farm to have high soil phosphate levels and two fields totalling 24ha with a phosphate index of around 2 were selected.

Machine-sowing of harvested seed was chosen as the most suitable method of starting off the reversion process. Natural re-colonisation was thought to be unlikely to produce the right levels of target species, since this requires plentiful supplies of nearby seed - something which could not be guaranteed, especially over such a large area.

A mixture of brush-harvested wildflower and grass seed was sourced from four local downland sites, including the Salisbury Plain Training Area, where there are several thousand hectares of good quality calcareous grassland. Using locally sourced seed increases the chances that the plants will thrive, as they will be better adapted to the local conditions.

After harvesting the last arable crop from the selected fields, a sterile seed bed was created by spraying with glyphosate and cultivating with a spring-tine cultivator to provide a good tilth. A few weeks later, in mid-September, the wildflower/grass seed mix was sown using a pneumatic fertiliser spreader, which blows out the seed from tubes spaced 1m apart along an 18m boom width.

Seed Sowing

The seed was mixed with kiln-dried sand to improve the flow of seed through the spreader and sown at a rate of 20kg per hectare. Four complete passes of the spreader were made to ensure good distribution of the seed. The fields were then rolled with a Cambridge roller to ensure good contact with the soil.  The approximate cost for this (in 2008) was just under £900 per hectare, split between herbicide (17%), seed (76%), dried sand (2%) and labour and diesel (5%).

Early establishment and management

In the first year, the sites looked very patchy, although many chalk grassland species were showing by midsummer, such as salad burnet and small scabious. The fields were topped once in early May, timing the cut to catch most of the black grass and other unwanted plants such as thistles and docks before seed set.

Patchy coverage in the first spring after autumn sowing

An early cut avoids topping more than 25% of the yellow rattle, which is a key species in the arable reversion process. Yellow rattle is semi-parasitic on grasses and clovers, suppressing grass growth and increasing the light available for other wildflowers to prosper.

The side shoots from the yellow rattle and the other chalk grassland species were then allowed to flower and set seed and a further cut was made in July. The arisings from this July cut were collected and removed to prevent mulching and help drive down the nutrient levels, allowing the flowering species to compete effectively with the grasses.

Yellow rattle helps to keep the sward open

Sheep were introduced in the Autumn/Winter to create a short open sward with occasional tussocks, which created some habitat diversity in an otherwise flat field. In the following two years, hay crops were taken to further reduce soil nutrients levels, with aftermath sheep grazing from autumn to early spring. Supplementary feeding was avoided to prevent the import of nutrients.

Assessing for habitat quality

By the third year after sowing the plant community was typical of early grassland creation, with a large diversity of species present - 37 species were recorded inside the assessment quadrats, with a further 21 species elsewhere in the sward. These included species which are characteristic of chalk grassland and typical of nutrient-poor conditions. Analysis of the species makeup showed that there were five 'dominant' or 'abundant' wildflower species: yellow rattle, ribwort plantain, black medick, self-heal and white clover. Of those recorded at lower frequencies, several were chalk indicator species, including harebell, perforate St. John's wort and field scabious, as well as those listed in the Natural England ‘species indicators’ table below. The woodier perennials like greater knapweed, oxeye daisy and wild marjoram were establishing well.

Of the typical grasses present, sheep's fescue was dominant, with quaking grass, upright brome, yellow oat-grass, meadow oat-grass and common bent also recorded.

Year three - a herb-rich sward is establishing

The following table shows the criteria for success set out by Natural England for this type of habitat and how the reversion fields measured up against these criteria:

The importance of soil fungi and organic matter

We found that some species were slower to establish than others. This is likely to be due to the abundance and diversity of mycorrhizal fungi present in the soil. Intensive arable agriculture reduces this diversity, and some plant species will not be able to exist on the land until the correct fungi arrive. It wasn’t until about four years after the start of the reversion that the first signs of fungal colonisation, the ‘fairy rings’, could be seen and species such as dropwort and devil’s-bit scabious began to appear. It was more than five years after sowing before any orchids were spotted, which is likely to be an indicator of the developing populations of mycorrhizal fungi.

Some good indicator species like saw-wort, have still not been recorded, although we know the seed was sown. This could be due to the soil conditions or plant associations not yet being right for them to get established.

Fairy rings show signs of mycorrhizal fungi

The levels of organic matter in the soil were extremely low to begin with, at around 2%, which is consistent with the land having been in long-term continuous arable cultivation. The establishment of permanent grassland will cause the organic matter levels to increase over time, especially where the land is grazed. The soil analysis results for 2017 showed that the levels in the early reversions had generally gone up to around 5-9%. The increase in soil organic matter goes hand in hand with bacterial and fungal diversity and with the locking up of carbon, making semi-natural grasslands like chalk grasslands in our landscapes a natural way of helping to tackle climate change.

Achievements for fauna

We saw an amazing transformation from cultivated land to herb-rich sward by year three, and even by the second summer after sowing there was visibly and audibly more insect life in the new grasslands. The most obvious insects are of course the butterflies, and from the second year we saw meadow brown, common blue, small blue, dark green fritillary , marbled white, ringlet and small skipper.

Other insects, such as moths, beetles, bees and flies had also colonised the grasslands, although no formal assessment was made in the early years to compare with the baseline survey taken at the start of the reversion process. However, in an invertebrate survey undertaken in 2016, one new BAP Priority species (the bumblebee Bombus ruderatus) and eight new Nationally Scarce species were recorded, including the six-belted clearwing moth and the picture-winged fly Merzomyia westermanni.

When farmland is taken out of cultivation there is a risk that some bird species associated with arable cropping might decline, so it was important to ensure that the key requirements of these species were maintained. To help ensure seed food availability for farmland birds on the farm, some strips of wild bird seed mixes were sown alongside natural features such as hedges. Farmland birds are regularly seen in the floriferous arable margins and the bird seed plots, and whilst the figures from the Common Bird Census recording took a little while to show real signs of benefit, the ongoing provision of suitable habitat has reaped rewards. Local populations of farmland birds such as skylark, yellowhammer, linnet, lapwing and corn bunting, all of which are currently species on the Red List of Conservation Concern, have either increased or been maintained, as the chart below shows.

Lessons learnt

We have learnt a couple of important technical lessons regarding nutrient levels and seed sowing as a result of our reversion projects.

  1. Where we started the reversion process with a phosphate index of around 2, it sometimes produced a thick grass-dominated sward very quickly, crowding out some of the sown wildflowers and emphasising the need for a lower initial phosphate index. Although haymaking can be used as a way of reducing nutrient levels in the soil once the wildflower seed mix has been sown, we have found that growing barley for a couple of years without a compound fertiliser prior to starting the reversion is a more cost-effective way of reducing the levels of key nutrients, especially available phosphorous. These crops are best grown with the application of ammonium nitrate fertiliser; this helps the barley pull up the phosphates from the soil without contributing to the nutrient load, as nitrates will leach readily from chalk soils.

 

  1. We did not mix the seed with any other agent at first and found that the seed clumped together in the machinery (termed 'bridging'). Mixing the seed with the kiln-dried sand improved the flow, but we have found in other reversion projects that it is even better to use a fertiliser spinner, which broadcasts the seed through a wider aperture.

 

All photos supplied by Patrick Cashman, site manager RSPB Winterbourne Downs

For more information, contact: patrick.cashman@rspb.org.uk

 

 

Case Study: Carabid beetles for natural-enemy pest control

Author: Kelly Jowett:

If there was an agent acting within your crops that could reduce eggs and first instar larvae of the cabbage root fly by up to 90%; reduce emerging wheat blossom midge by 81%; and reduce seed stock of crop weeds in the range of 65-90%, then I’m sure you’d want to keep it in there. Well, with a little effort you can have this voracious destroyer of pests working across your farm. Carabid beetles, sometimes known as ground beetles, eat ALL major crop pests, and weed seeds too, and are present in all farm habitats across the UK. This makes them ideal agents of natural enemy pest control.

Natural enemy pest control is a bit of a mouthful but is just what it describes: the eating of crop pests by the predators that would control them in a natural system. The problem for natural enemy pest control is that we are not dealing with a fully natural system. Since the post-war agricultural revolution, farmland has been subject to tremendous change. Over time this has caused substantial decline in the populations of carabid beetles and other natural enemies. Unfortunately, pest species are adapted to bounce back quicker - especially since large crop areas are ideally suited to support population booms. Whilst pesticide sprays are necessary in this system, they compound the problem - hitting the predators as well as the pests, added to associated resistance building.

The importance of biodiversity

Carabid beetles are incredibly variable. Of the 350 species in the UK, 30 of these are common in farmland. They range in size from 2mm to 3cm in length; some can fly long distances, some run up to 16cm per second; some breed in the autumn, and some breed in the spring. Each has their own habitat preferences, meaning that they are active at different times, tolerate different weather and farm management practices, and are better at eating different crop pests. Therefore, having a diverse range of carabid species will mean that you have the best chance of effective pest predation.

So what can we do to help boost carabid numbers and diversity?

Luckily carabid beetles are well studied and we already know a lot about what they need to thrive. We can break this down into areas to feed, areas to breed, and areas to shelter.

Areas to Feed

Of course we want them to feed in the crop or pasture area when pests are there- but pests are not there all the time (luckily for us!) to support the carabid beetles needs. So semi natural areas are essential to provide the invertebrate and plant resources for all year round food. Conservation headlands, grass/ flower margins, beetle banks and taking field corners out of management, can all provide these close to productive areas, so carabids can move quickly into the crop to eat the pests they prefer, when they appear.

Areas to Breed

Carabids lay their eggs in the soil, hatching into larvae- which take around 6 months to grow, before they pupate and emerge into adult beetles. The larvae are actually predatory on crop pests too, and eat more than adults as they need a lot of protein to grow. Some larvae also eat weed seeds, which is particularly useful as they live in the top soil levels in the crop area. To help larvae grow undisturbed in crop areas, minimum tillage systems may be useful.

Areas to Shelter

Carabids have two main periods when they need shelter: hibernation, and aestivation, which is a summer rest period when conditions are too hot and arid. At these times, the beetles take advantage of permanent habit with structure that creates a protective microclimate- such as hedges, ditches, banks, and at a small scale the tussocks created by some grasses.

Another important aspect is the shelter from machinery and chemical applications. These can cause direct mortality, or affect the carabids ability to feed and breed, so safe areas near to crops allow some beetles to thrive and repopulate when such management is necessary.

Linking up farm habitats

To preserve or enhance the diversity of carabids on your farm it is important to have a range of habitats, but also for them to be linked up. Firstly populations need those seasonal and foraging movements, but as conditions change, different species can immigrate into your farm from surrounding areas to boost your assemblage of species. Carabids move in the landscape in a variety of ways, flying species will use habitats as stepping stones, whilst running species may need ‘corridors’ of hedges and margins to encourage them to move around the farm.

Farm habitats for beetles. a) grass and flower margins, along with hedges provide food resources year round, and connect other habitats;
 b) beetle banks create stable resources in the centre of fields, to encourage beetle presence in crop areas;  (c) Peter Thompson
c) taking corners out of management encourages scrub and tussocky grasses- ideal for sheltering carabids.

Farm habitats for beetles: a) grass and flower margins, along with hedges provide food resources year round, and connect other habitats;  b) beetle banks create stable resources in the centre of fields, to encourage beetle presence in crop areas;  c) taking corners out of management encourages scrub and tussocky grasses- ideal for sheltering carabids.

But there is still work to be done

Although scientists have done a lot of research on carabids, there is still a lot we don’t know. My recent work has shown that different species are associated with different landscape features such as field boundary habitats, crops, soils, and management such as tillage regimes. If we can better understand which habitats are most beneficial for different beetles, it will become possible to tailor your farm habitats to get a good selection of predatory species that suit a farms particular pests.

Pitfall trapping to monitor farm habitats

Pitfall trapping is a quick and easy way to see what carabids you have on your farm, and if you do pitfall trapping periodically, you can track how the populations vary over time relative to your farm management interventions. For details see my factsheet:

 How to pitfall trap on your farm: Factsheet

Feed-back to scientists, especially me!

The main knowledge gap is how these habitats work in practice, over time. This is where we need to work with farmers closely, monitoring farm habitats, seeing what works, where, and why. But also, crucially, we need to know which interventions fit well into your farm business. Even if something works for beetles, if it’s going to be difficult for farmers to apply, it will not be widely applied!

Which leads me on to my plea: I need farmers to take my survey!

Watch my animation: Here.

Take a short introduction to ID quiz: Link to ID Quiz

Then take my beneficial beetles survey to tell me your opinions on carabids, management that may be useful for them, and monitoring. Link to survey

If you are motivated after reading this article to carry out pitfall trapping or set up monitoring on your farm, I would be happy to help with advice, and support with verification of carabid identification.

Email : Kelly.jowett@rothamsted.ac.uk or contact me on twitter: @kelly_jowett

Case study: Insecticide-free arable farming

Author: Martin Lines
Farm: Papley Grove Farm, Cambridgeshire: 160 ha farmed in-house plus 360 ha contract farmed

(c) Martin Lines

Aims:

In 2013, my agronomist recommended that I spray for black bean aphid, but conditions were too wet and windy for a period of ten days, after which aphid numbers had dropped and ladybirds were eating them, so I decided not to spray and saw no detrimental impact on my gross margin. This got me thinking about the pros and cons of insecticide use, as insecticides were becoming less beneficial due to resistance and were taking out the beneficials that were doing the natural pest control. Prior to this, I had already stopped using Dursban to control Orange Wheat Blossom Midge (OWBM) about 15 years ago because of the damage I could see this did to the insect life as a whole in the field. Also, my experience of contract farming an area of organic farmland for ten years led me to realise that insecticides were not necessary for yields in this system: the reduced yield of the organic land seemed to be more down to crop nutrition and weed pressure than pests or diseases. So I took the decision to do everything I could to control pests without insecticides and monitor the impacts on my yields and profit margins.

I took advice from my Frontier agronomist, who is very understanding of where I am coming from and where I want to get to. I also get ideas from events and social media.

Management:

Prior to 2013, insecticide spray decisions were based on a combination of thresholds and convenience. As the products cost £1.60 / ha and the operation cost £5 or £6 / ha, I would occasionally add an insecticide to a fungicide or herbicide application if its use was likely to be necessary, to save the money of running two operations. After 2013, the convenience use of insecticides stopped and I monitored against thresholds for the first few years and did not find a single justifiable case to spray. There were anxious moments in the early years when I would see signs of Barley Yellow Dwarf Virus (BYDV) on small areas, but in experience this did not result in a net economic loss. Pest numbers seem to have been suppressed from exceeding thresholds from year one. Subsequently, I keep an eye out on forecasts and look for visible signs of an issue but am more relaxed that I have built up the resilience of my soil, crops and beneficials to have confidence that I may never need an insecticide again. I am not saying that I will never use them, but as yet, I have not had a need to. I occasionally see OWBM, but timing of control for these is so critical, and the use of a summer insecticide is so damaging that I have resisted the urge I would have previously had to resort to the can. Cabbage Stem Flea Beetle (CSFB) problems seem to occur whether I use insecticides or not and the way I look at it now is that the more you use the chemical, the greater the risk of resistance build up.

I have broadened the range of crops I grow. Previously, I stuck to a rigid two wheats, oilseed rape, one or two wheats, beans, all winter-sown, and the ratio of crops in the ground would be roughly 70% wheat, 20% oilseed rape, 10% beans. Now I have added winter and spring barley and have no fixed rotation, tailoring the cropping in each field to weed pressure and soil health. So, for example, if I have a black-grass problem then I will not go with a 2nd wheat, even though this gives a better return than a break crop. In general, I grow less wheat, more barley, less oilseed rape and more beans than previously. I now average about 40% wheat, 30% barley, 20% beans and 10% oilseed rape. The reduction in area of oilseed rape is more due to the challenges of dry August / September than issues with CSFB. On paper this would seem like a less profitable rotation, but in reality, I have slashed my cost of production, which has more than made up for loss of yields and crop values and my net profits have increased. Books also say that incorporation of spring crops to reduce black-grass levels results in a net loss in profits, but in reality, incorporation of the full range of Integrated Pest Management (IPM) techniques more than makes up for this through reducing costs of production.

Ladybird on winter beans (c) Martin Lines

I use pest resistant varieties where possible, but take decisions based on the best contracts that I can get, so this is not a major consideration. I have moved back towards traditional recommended cropping intervals, but this is a balance to have full IPM and maintaining a balanced rotation, so unlike virtually all farmers, I am moving back towards five to six years between oilseed rape crops.

I drill cereals after mid-October if weather allows, rather than September to reduce black-grass and autumn aphid pressure. I avoid over-feeding crops with nitrogen fertiliser in one application to prevent rapid growth, making the crop more prone to pest and disease pressure.

Making the habitats to enable the beneficial insects and spiders to thrive is key to the success of this system. I started off with flower-rich margins around the outside of the fields, and now have been adding flower-rich strips every 4th tramline (120m) to improve natural pest control and insect pollination. I am forever increasing my habitat areas voluntarily until my agri-environment agreements expire and allow me to top up the payments based on the areas I am taking out of production. I see the benefits of the in-field strips on the yield maps of my oilseed rape and beans, with yields being 5-20% greater next to the strip and tailing off further into the field: this also reflects my observation of the number of bumblebees I see across the fields. The yield response is probably a combination of the effects of increased insect pollination and increased natural pest control. I have not looked at whether the enhanced pest control next to the flower strips shows any benefits in my cereals yields yet.

Field margin in flower at Papley Grove Farm (c) Martin Lines

What area/% of cropped land is now out of production for AES / voluntary habitats compared with pre-2013?

I have around 9% on rented land and 12% at home. I also see increasing soil organic matter and, where soil structure allows, direct drilling of crops as measures that benefit the natural pest predators in providing a more functional soil ecosystem within which they can thrive. Many of the measures I have adopted in the transition to regenerative agriculture have multiple benefits, and it is difficult to tease out individual cause and effect impacts.

As well as stopping the use of insecticides, I have also cut down on the use of herbicides, fungicides and molluscicides. I put this down to improved soil health, crop health and better rotations – a consequence of the holistic regenerative agricultural system. I am conscious that pesticides as a whole do damage to the functional ecosystem that boost my yields, and I am looking to reduce use across the board. I monitor slug levels, but if I see lots of beetles in the field, I see if they can do the job first and only treat areas that seem to be struggling. I am not looking to eliminate slugs from the field, but keep them at manageable levels, whilst maintaining a thriving food chain for the beneficials.

This year, I have tried a few new ideas to further benefit from the IPM approach. I have sown a mix of wheat varieties in my wheat field to avoid the pest and disease risks that can arise from a single variety monoculture. I have also undersown my beans with clovers and tried intercropping my oilseed rape with phacelia and clovers to see if these measures will disguise the crop from pests and boost beneficial numbers further.

Achievements:

Overall, crop yields are a little lower, but I think this is more because of the switch to direct drilling than the loss of insecticides. The yield losses are more than made up for by the reduction in costs of production and the net margins are up, despite reducing the areas of wheat, our most profitable crop. Last year, cost of production of my wheat was c.£72 per tonne, about half of the average across my peers. Prior to 2013, profit margins had stagnated, but the trend is now definitely upwards. The total farm profit is so variable from year to year, it is not possible to put an average percentage figure on it yet. I do feel my business is more resilient to the market and weather pressures.

(c) Abi Bunker, RSPB

There are visibly more beneficial insects and spiders. I don’t know what they are, but the ground is alive with them. There is noticeably more wildlife overall, especially the birds. The incidence of pest levels exceeding economic thresholds has declined to zero. This was apparent from year one, but probably accrued over the first few years. Prior to 2013, I might spray a cereal crop with insecticides in the autumn against BYDV, at ear emergence and potentially again for OWBM. In oilseed rape, I would spray between two and four times in the autumn for CSFB.

I also believe there are benefits in this approach to my personal health, with fewer potentially harmful chemicals to deal with.

There is no blueprint to IPM and I feel it has to be a whole farm and landscape approach as it is not as easy as conventional farming with pesticides. Farmers need support through Knowledge Transfer platforms to help them to reduce pesticide use – this is not readily available beyond organic farming.

Case Study: Adding Value to Chalk Grasslands: Creating Chalk Banks to benefit butterflies and other insects.

Author: Lynne Roberts . Farm: The RSPB’s Manor Farm, Newton Tony, Wiltshire

Aims and setting:

Manor Farm is a 296 ha working farm strategically placed between two of the largest tracts of semi-natural chalk grassland in the British Isles – Salisbury Plain and Porton Down. The RSPB purchased Manor farm in 2006 and have been reverting former arable land back to species-rich chalk grassland to create a landscape-scale stepping stone between these two areas.

Whilst this reversion has been very successful in establishing flower-rich grassland, even after several years the ex-arable fields still have unsuitable soil conditions for the plant species typical of very thin, nutrient-poor chalky soils. The fields are also rather flat as a result of historical cultivation, lacking the humps and hollows of natural grassland which help to create a variety of microclimates for a wider range of plants and insects.

For these reasons, in 2013 it was decided to create two large mostly south-facing banks to support viable populations of species characteristic of thin, chalky soils. Butterfly banks and scrapes can provide ideal conditions for butterflies, with sheltered sunny spots and bare ground for basking, alongside a mosaic of nectar-rich flowers for foraging adults and specific foodplants for growing caterpillars.

Funding for the creation of the banks was provided by the SITA Trust (now SUEZ) “Conservation of the small blue butterfly at RSPB Winterbourne Downs” project, and the Biffa Award “Saving a special place for Wiltshire’s endangered butterflies” project. Appropriate permissions for the work were also obtained.

Construction:

The site for the butterfly banks was flat terrain with a 20cm layer of flinty loam over chalk. Two large banks measuring 150m x 12m and 180m x 12m were constructed in two different fields. The loam topsoil was bulldozed into an S-shaped mound, oriented so that most of its length faced south. The mound was then covered with the chalk from the beneath the soil, leaving a wide 'scrape' area of bare chalk alongside.

The S-shape ensures that there are sides facing all possible directions, creating a variation in topography and diverse range of micro-climates. The idea is that this helps to increase the resilience of both plants and insects to the more extreme conditions predicted as a result of climate change. In the mornings, butterflies, bees and other warmth-loving insects can warm up on the east-facing side of the banks, which catches the early morning sun. During the main part of the day, they can use the warm, sunny, south-facing side. If it gets too hot on the south side, the insects can retreat to the north-facing side. As expected, during the middle part of the hottest July day on record in England in 2015, all the bee activity was on the banks’ north-facing slopes.

Construction begins

The first bank was initially seeded with a generic chalk grassland and wildflower mix as well as kidney vetch and horseshoe vetch, which are vital food plants for small blue, chalkhill blue and Adonis blue butterflies. On the second bank, only the kidney vetch and horseshoe vetch were introduced. The banks could have been left to regenerate naturally, but the butterfly foodplants were not growing in the vicinity and therefore seeding with specific species was preferred to ensure that the right plants established.

Development over time and ongoing management

The vetches were the first plants to establish and were flowering in the first summer after autumn sowing. Over the following two years other species, such as small scabious, ribwort plantain, harebell and quaking grass appeared, the coverage developing into a patchwork of abundant flowering species interspersed with bare areas - the ideal structure for butterfly habitat.

Vetches establish quickly on the bare chalk

The vegetation on the banks has become denser over time but has required little ongoing management as the tough conditions prevent many unwanted species from colonising. Sheep are our management tools, grazing from August onwards, when most flowering is over. This helps us to keep on top of any scrub encroachment and keeps the sward open, with some disturbance of the ground surface to create germination opportunities. Cattle would probably cause damage to the banks, so are avoided.

Where necessary, brush cutting is carried out in the summer and the arisings removed and taken to other areas of the farm which are species-poor and could benefit from wildflower sowing.

Brush cutting the coarser vegetation

Achievements:

Colonisation of the banks by breeding small blue butterflies was impressively quick - within the first three years, as the kidney vetch established readily. The abundance of suitable foodplants is particularly important for sustaining viable populations of butterflies, so the fact that small blues were seen on the banks in August, probably a second brood from eggs laid in June, was a good indication that suitable habitat for breeding had been achieved.

Small blue on its larval foodplant, kidney vetch

Other chalk grassland butterflies have also been recorded on the banks in the last few years: common blue, brown argus, marbled white, dark green fritillary and, excitingly, the marsh fritillary, a species in severe decline which has been attracted to Manor Farm by the abundance of scabious plants in the grassland. Good numbers of these species are now being seen on the farm as they are moving in from the neighbouring strongholds on Salisbury Plain and Porton Down. We have yet to record chalkhill blue, but the Adonis blue was a new record in 2018, so hopefully it will just be a matter of time before the chalkhills arrive.

The diversity of flora species continues to develop, with some of the less common chalk specialists such as devil’s-bit scabious, starting to appear on the banks.

In addition, we have shown that the fields containing the banks can still be used as grazing land, albeit in a carefully managed way.

Our experience and lessons learned:

Five years on we found that some plants had been harder to establish on the banks than others. The pioneer species kidney vetch and horseshoe vetch, two of our key butterfly food plants, established readily from seed and plug plants were not required. However, we didn’t have the same success with common rock rose, the food plant of the brown argus and cistus forester moth. This was easier to establish from plugs, although the sown seed may germinate eventually when conditions are favourable and the seed coat has weathered a little. Plugs are more expensive, so a pragmatic approach may be to try sowing seed first and then supplementing with a few plugs after a couple of years if the seed has not germinated. Germination rates of common rock rose can be improved by scratching the seed surface (scarifying) prior to sowing.

Where we sowed the generic mix, some of the taller plants have become dominant, greater knapweed particularly, shading out some of the foodplants, such as horseshoe vetch. We have therefore had to manage some of the less desirable species in order to help the key plants thrive.  This was not such issue on the second bank, where we had just sown the foodplants, with just the odd thistle to deal with.

We suspect that by creating the base of the banks from the flinty loam topsoil, the longer rooted chalk grassland species may be accessing nutrients from this base and gaining an advantage. Ideally, the bank would be created from pure chalk and the removed soil utilised elsewhere. A chalk-only bank would create the harsher alkaline conditions which favour the more extreme chalk specialists, including the kidney vetch and horseshoe vetch, and would slow the rate of encroachment by scrub species.

Although our butterfly banks are very large it is important to note that banks of any size can make a big difference to the survival of butterfly populations - even just moving soil around to create variation in the topography of reverted arable fields or pasture can help. Butterflies exist in small populations which are linked to create larger ‘metapopulations’, so even quite small areas of suitable habitat could provide a vital link in the chain.

All photos supplied by Patrick Cashman.   
For more information, contact: patrick.cashman@rspb.org.uk

Further examples of butterfly banks

Organisations such as Butterfly Conservation and Buglife have been constructing butterfly banks on several sites, both rural and urban, as a way of creating breeding habitat suitable for a number of different butterfly species. For further information see the following links:

Butterfly Conservation Fact Sheets

Case Study: Bare Ground for butterflies and moths

Case Study: British dung beetles – here to help

Author: Ceri Watkins, Co-Founder of Dung beetle UK Mapping Project

Species: Dung beetles

Why is farmland important for these species?

There are approximately 60 species of dung beetle in the UK. They are not the ‘ball rollers’ seen in warmer countries and on TV, instead they live inside the dung pile (dwellers) or in the soil beneath it (tunnellers). Livestock grazing provides much of the dung required for the survival of these beetles, although other animals such deer and badgers also contribute. Some species are rather specialised and require exacting conditions. For example, Volinus sticticus prefers horse or sheep dung in the shade and Onthophagus joannae is a sun loving beetle that favours sheep dung on light soils. Others are less fussy and have few specific requirements.

It is possible to find dung beetles at work all year round. Several species are winter active, although the vast majority are found in the spring, summer and autumn. Given the right conditions, dung beetles can decimate a pile of horse poo or a cow pat in just a couple of days.

Volinus sticticus (c) Katherine Child  

Onthophagus joannae (c) Katherine Child

How do dung beetles benefit farms?

Dung beetles provide a wide range of ecosystem services that help to maintain healthy pastures and soils. These include the most obvious, the consumption of dung thereby removing it from the fields thus reducing pasture fouling, but also some that you may not have considered. As the beetles tunnel down through the soil, burying the dung for breeding purposes, essential nutrients are recycled within the soil profile. This improves grass growth and provides a direct benefit to grazing animals. The larger species such as the Minotaur beetle (Typhaeus typhoeus) can tunnel a metre or more, this action breaks up the ground and improves drainage, especially useful on clay soils.

In addition, dung beetles also reduce nuisance fly populations by transporting phoretic mites that eat fly eggs and help control intestinal parasites by reducing dung suitability for worm larvae. The beetles are also an important food source for many other farmland favourites such as bats and birds.

Onthophagus similis with phoretic mites (c) Ceri Watkins

Habitat management

Continuity of the dung supply and diversity of habitat are key factors in supporting a diverse range of dung beetle species on the farm. If possible, maintain some outdoor grazing year-round, even if only a few animals. Planting a group of trees and grazing within them will provide variety of forage and shelter for livestock and support the shade loving dung beetles too.

Broad spectrum livestock wormers such as avermectin are detrimental to beneficial dung invertebrates. These chemicals are excreted in the dung for many weeks after treatment and a range of lethal and sub-lethal effects occur depending on the concentration. Such effects include slowing beetle larvae development, reducing the size attained at adulthood and reduced breeding capacity.

Cutting down the use of chemicals on the farm with a sustainable worm control policy that includes monitoring with faecal egg counts will help. Treating animals only when necessary will save money and also slow the rate of anthelmintic resistance. As a natural alternative in a rotational system, consider using herbal leys. Sainfoin, birdsfoot trefoil and chicory all have anthelmintic properties. The latter has been shown to reduce worm burden in sheep by as much as 40%. In permanent grasslands, mixing up cattle and sheep grazing works by reducing the stocking density of the parasite host – cattle and sheep worms are different species.

Benefits

Supporting dung beetles on your farm not only helps keep pasture and livestock healthy, it also represents good economic sense. It has been estimated that dung beetles save the UK cattle industry £367 million per annum through the provision of ecosystem services (Beynon et al., 2015). So, it really does pay to look after these useful little creatures.

For further information and dung beetle identification resources, please visit the Dung beetle UK Mapping Project website or get in touch via email or twitter.

Case Study: Using hay strewing as a technique to create species-rich grassland

Author: Jennifer Palmer

Farm: High Burnham Farm, Epworth

Aims

High Burnham is a large (+300ha) arable farm.  As part of the RSPB’s Axholme and Idle Farmland Bird Initiative¹ (Lincolnshire), an opportunity was identified to revert an arable field corner to a species-rich meadow.  The 1.7ha field corner sits within the base of a large L-shaped arable field.  Because of the clay-based soil type, the field corner lay wet so was deemed unsuitable for arable cropping hence it was left out of production for four years.

The low-lying field corner lends itself to a pastoral management and is less than 200m from Rush Furlong Meadow SSSI.

This will be the only parcel on the holding managed as grassland.  It is anticipated that hay will be cut by a local contractor used by the Lincs Wildlife Trust and aftermath grazing will be carried out by a local grazier.

Management

Verbal advice and a written proposal were provided to the landowners on species-rich grassland establishment and management.  The RSPB’s Hay Meadow and Arable Reversion topic sheets were used to supplement this verbal and written advice.  The landowners understood the principles of grassland management through knowledge of a local grassland SSSI.

Hay strewing is a tried-and-tested method for enhancing the botanical diversity of species-poor grassland² and can also be used to create diverse grasslands on arable land³.  It entails taking freshly cut ‘green hay’ from a local donor site and, on the same day, strewing (spreading) it onto a suitable receptor site.  It is a cost-effective method and ensures that the received seeds are of local provenance.

Two donor sites were identified and Lincolnshire Wildlife Trust kindly donated and cut the hay from Sedge Hole Close, a damp meadow (MG4 National Vegetation Community) containing cowslip, great burnet, lesser knapweed, oxeye daisy and cuckooflower.  Natural England consent would have been required for using SSSI hay.

Loading a trailer with green hay at East Lound with Matt Cox Lincs Wildlife Trust

Technical advice was followed to ensure the receptor site’s soil was suitable, through testing phosphorus (P) levels.  The soil sample results showed a P Index of 1 (low) so was deemed acceptable.  The farmer prepared the site by spraying off weeds using herbicide and creating a create a fine, firm and level seedbed, avoiding looseness at depth.

The site has no historical significance.

Because the donor site is an NVC MG4 vegetation community, containing abundant great burnet, we followed advice from a floodplain grazing meadow conference (attended by Helen Norford of Yorkshire Wildlife Trust) to spread the hay at reasonable depth (up to 10cm).

Once strewn, in the first year the vegetation growth should be cut up to 4 times and then the grassland should be treated as a traditional hay meadow thereafter.

Because the donor site was smaller than the receptor site (0.9 and 1.7ha respectively) we found that we had a deficit of green hay for the receptor field and a ratio of 1:1 (as recommended by Dr Duncan Westbury) would have worked better.  Partners therefore plan to revisit, survey and repeat if necessary next year.

Black grass growth will also be re-sprayed off this year.

The cost of the green hay was free as it was donated by Lincolnshire Wildlife Trust.

There was a minimal fuel and labour cost incurred by the farmer transporting the two loads of green hay from the donor site to the receptor site.

Achievements

Breeding skylarks have been recorded in adjacent fields during RSPB bird surveys and breeding skylarks are also recorded at Rush Furlong SSSI so the parcels should attract skylarks.  The parcel also offers potential lapwing nesting habitat, providing the additional scrape excavation works are undertaken. There are records of yellowhammers in the hedges and reed buntings nesting in the adjacent OSR crop.

Sitting within the Humberhead Levels NCA, the project meets multiple NCA priorities - the creation of lowland meadow (biodiversity priority) and permanent grassland (landscape priority).

Advice for other farmers

Don’t be tempted to miss out the soil testing step! If phosphorous index is anything above low, species-rich grassland creation may not be viable for your site at this moment in time.

Ground preparation is really important and if strewing onto established grassland, really open up the sward so that lots of bare ground is showing.

Orchids may take several years before they appear so don’t be disheartened if nothing happens for the first few years.

Expect to have to consider repeating the method to ensure a diverse sward.

Additional information

¹ The Axholme and Idle Farmland Bird Initiative covered the river catchment area in the Idle Valley and Isle of Axholme, an area of Lincolnshire, South Yorkshire and Nottinghamshire recognised as being nationally important for its farmland bird assemblage.  The project area was one of the RSPB’s Farm Advice Focus Areas and ran from 2012 to 2018 combining farmland bird monitoring and farm conservation advice.
² Natural England Technical Information Note TIN063, Sward enhancement: diversifying grassland by spreading species-rich green hay.  Also through own experience on land owned by the Malvern Hills Trust, following advice from Dr Duncan Westbury of Worcester University.
³ Visit to arable reversion hay strewing site led by Professor Ian Trueman, 15-18 June 2012, FSC Shropshire Wildflower Weekend.
⁴ Natural England Technical Information Notes: TIN035, Soil sampling for habitat recreation and restoration and TIN036, Soil and agri-environment schemes: interpretation of soil analysis.

Case Study: Helping hedgehogs on farmland

Author: Nida Al-Fulaij, Grants Manager, People’s Trust for Endangered Species

Species: Hedgehog

Why is farmland important for this species?

Hedgehogs are found throughout the UK in all habitats. They have historically been associated with farmland for centuries. Hedgehogs are insectivores, foraging in fields and on grassland for worms, and along field margins and at the base of hedgerows for beetles, snails and other invertebrates. They are considered a generalist species, inhabiting most areas of our countryside, our villages and many areas of our towns too. However, as the dominant habitat in the UK, farmland is particularly important for hedgehogs.

Hedgehogs, like all animals, need to feed, hide from predators and find mates. A variety of habitats that provide foraging areas and secure nesting sites is ideal. Both arable and pasture land can support healthy hedgehog populations. Wide, species-rich hedgerows with buffers of grassy margins on either side provide safe ‘highways’ for hedgehogs to move around the landscape. Hedgerows with wide bases that are managed on rotation should have healthy invertebrate populations for hedgehogs to feed on. Old hedges with dense root systems and lots of deciduous leaves are ideal for them to use as nesting sites, both during the summer and in winter as hibernation spots.

The denser the network of hedges, the more securely hedgehogs can move around, and the higher the availability of prey species for them to feed on.

Recently ploughed fields can provide a bounty of earthworms and other prey; hedgehogs can be found in-field taking the opportunity to feed on invertebrates once crops have been harvested.

Recent studies show hedgehogs are found nearer to farm buildings. These areas could be providing safety from predators on farmland with less robust and fewer hedgerows, and larger fields.

Hedgehog (c) Ben Andrew (rspb-images.com)

Habitat management

Hedgerows:

Increasing hedgerow availability provides more nesting and foraging areas for hedgehogs. Ensure that hedgerows are species-rich, contain native trees and are as wide, high and dense as possible. Maintaining hedge bases at least 2m wide with minimal or no gaps provides secure safe nesting sites. Managing hedgerows on a 3 year rotation ensures that hedges remain diverse and robust.

Field margins:

Field margins provide buffer zones to protect hedgerow bases. 2m margins in arable fields and 3-6m margins in pasture ensures the hedges are protected from trampling and grazing, whilst the grassland provides extra invertebrate prey. Beetle banks also provide buffer zones and extra foraging areas.

Fields:

Smaller field sizes with a mixed crop provides greater variety, and therefore greater food security, for hedgehogs and other wildlife. Increasing hedges and field margins on farms with fewer, larger fields, provides habitat for hedgehogs. Reducing tillage or moving to no-till or conservation agriculture reduces soil compaction, increases soil invertebrates and improves and increases the depth and quality of the soil organic layer.

Pesticide & herbicide use:

Reducing pesticide and herbicide use means that more invertebrate prey, in particular earthworms, will be available on farmland for hedgehogs to feed on.

The above management measures recommended to provide a healthy landscape for hedgehogs are typically those associated with traditional farming practices. There should be no problems, though many of the measures may be more time-consuming than those associated with farming on a larger scale.

Hedgerow with grassy margin (c) Gethin Davies

Peoples Trust for Endangered Species (PTES) and British Hedgehog Preservation Society (BHPS) have created an advice note detailing management and stewardship options that will benefit not only hedgehogs but other wildlife too (see link below).

Benefits and costs

Creating and managing hedgerows sensitively has financial costs but there are stewardship options available; individual ones for the management regimes listed above are detailed in the attached advice note.

Managing a farm for a species such as a hedgehog involves looking at the farm as a whole. Unlike species that fly, such as butterflies, hedgehogs needs the entire landscape to be suitable in order to thrive. Consequently, many of the management techniques recommended to improve habitats for hedgehogs will also provide a healthier landscape. A denser proportion of hedges and associated smaller field sizes both help to reduce soil erosion. Reducing tillage improves soil organic matter and reduces soil compaction.

PTES guide - How to help rural hedgehogs

Case study: Herb-rich leys

Author: Ian Boyd
Farm: Whittington Lodge Farm, Gloucestershire

Aims:

Whittington Lodge Farm has predominately thin Cotswold Brash soils on 280ha, mostly over 800 feet in altitude. The cultivated half of the farm was in a continuous arable system, but average yields meant it was only marginally viable and blackgrass was creeping in.

In 2015, it was decided to undergo organic conversion on all the arable area to combine with the fully organic grassland. Herb-rich leys were introduced into the rotation to build fertility for the organic cereals. They are grazed by an existing and expanded suckler herd of native Hereford cows and calves.

Cattle grazing a herb-rich ley at Whittington Lodge Farm. Image credit: Ian Boyd

Management:

The herb-rich leys contain at least 5 species of grass, 5 legumes and 5 herbs which all add to the biodiversity with varying rooting depth in the shallow soils. They are established by under-sowing in spring barley crops, broadcast with an Opico seeder/harrow once the barley plants have reached the 3 leaf stage. This way the undersown plants are still small enough not to interfere with the barley combining. Grazing can begin in the autumn.

The herb-rich ley can last for 4 years and can be grazed or conserved as hay or silage. It can fit in well with other grasslands like permanent pasture with the management of grazing livestock.

Mob grazing can help achieve the best from the leys. The cattle are moved frequently, usually daily, onto fresh grazing and a back fence stops them eating any re-growth after about 3 days. The adage is that you should not see the cattle’s knees when they go in and you should not see their ankles when they come out. Some of the herbage is eaten, some trampled and some left so that the root structure underneath the plants is maintained and re-growth is rapid.

Then, most importantly, the ley is rested for a couple of months to allow plants to flower and set seed before the next grazing. This will provide habitat for invertebrates, including crop pollinators, and improve soil structure and water infiltration.

Moving the electric fence is a daily commitment but it makes it easier to check and count the stock as they run past.

The cost of seed is significant but no nitrogen is required, and it is possible to incorporate this option into a Countryside Stewardship scheme and claim payments for it.

As the soil organic matter level is improved, more grass will be grown and stocking rates will be able to be increased. This system suits both cattle and sheep on organic and non-organic farms.

Achievements:

There are multiple benefits to herb-rich leys. When terminated, they provide an ideal entry to cereal crops for several years, organic or not. The arable weed spectrum is dramatically reduced, especially blackgrass.
Soil health and organic matters levels will have been increased with large amounts of carbon sequestered into the soil, far more than the effects of methane produced by the cattle.

The nutrient density of the beef will be greater when multiple species and biodiversity are eaten with knock-on health benefits for the cattle and consumer.

The farmland wildlife is a big winner here, with many different plants flowering producing nectar for pollinating insects and producing seed (and insects) for many bird species to eat. Skylarks nest everywhere, hares and roe deer love to graze it. Kestrels and barn owls hunt for short-tailed field voles living in the long grass and snipe are increasingly being seen looking for worms in the winter time.

It really helps to be organised and to have planned the rotational grazing before the start of the season. Access to water, ease of moving electric fences and having the cattle in the right place at the right date all have to be factored in.

This system really suits British native breeds of cattle, which can readily be managed to Pasture-for-Life standards (essentially no grain fed). Pasture-for-Life beef allows the opportunity to brand and market it yourself with a great story for a higher price than the beef commodity market can pay.

www.cotswoldbeef.com

Case Study: A farmland bird package on limestone soils

Author: Jeff Platts
Farm: Hazelmere Farm, Creswell, Derbyshire

Aims:

To provide summer insect food and seed food over winter for seed-eating birds, particularly targeting grey partridges and tree sparrows, and to provide suitable nesting habitat for lapwings on the arable land.

Management:

Hazelmere farm (270 acres) has been in the family for over 75 years, and is leased from Chatsworth Estates. I took the decision to leave dairying five years ago, and now the business concentrates on arable, with a livery and rural skills school on site.

Wild bird seed mix plots

To provide winter food for the seed eating birds on his land, I have included several plots of wild bird seed mix which have done very well on the free-draining, limestone based soil. The mix includes phacelia, kale, quinoa, millet and triticale with a handful of sunflowers also thrown in. The wild bird seed mix is re-established every other year and the land is prepared and drilled as if it is a normal crop. I occasionally get an infestation of flea beetle on the kale so a pesticide is used. A small amount of fertiliser is added to maintain nitrogen levels. The plots where the wild bird seed mix have been established were chosen to complement the adjacent land use such as hedges and margins with recognised bird populations.

The wild bird seed mixes have worked so well, I’m looking at re-sowing only one of them this year with the possibility of adding perhaps an additional row of quinoa or millet alongside another of the plots. The kale is showing through in this second year along with a reasonable amount of fat-hen which will also provide a good seed source.

Fallow plots

I have also included rotational fallow plots - it has proved very successful in encouraging lapwings to breed on the farm and I estimate there are slightly more than 20 breeding pairs. I’ve also seen flocks of up to 80 lapwings using the plots in the late summer.

Across the farm there are 51ha left as over-wintered stubbles after a spring cereal and, on average, 10ha are then sprayed off at the end of March and left as fallow after running over them with a light disc to break up the surface.

In the autumn, as long as there is no major weed cover showing, a single run with the cultivator or a light set of discs creates a suitable till and the cereal is then drilled.

There have been some issues with sterile brome on the fallow plot. After discussion with Natural England, the plot was left fallow all year including over winter and then cleaned up with a stale seed bed with a supplementary treatment with Roundup before being sown with another spring cereal this year.

Flower-rich margins

I’m currently looking at adding some additional floristically enhanced margins for grey partridge around some fields to increase foraging and breeding habitat. This will also benefit a wide range of insects, and other birds on the farm which feed their chicks on insects.

Achievements

Collectively, the wild bird seed mixtures, floristically-enhanced margins and fallow plots will provide an ideal package for farmland birds, giving the key requirements of winter seed food, summer insect food and in-field nesting habitat for ground-nesting birds, respectively.

The birds on the farm were surveyed in 2009 as part of the RSPB’s Volunteer & Farmer Alliance scheme. The survey picked up nine red list species of high conservation concern, including grey partridges and lapwings, and thirteen bird species of medium conservation concern, including bullfinches and reed buntings.

Of these, the density of lapwings recorded on the farm during the summer and autumn are testament to the benefits of fallow plots to this species with the number of lapwings breeding on the farm having increased since the adoption of this measure. It also provides a winter food source for those lapwings which over-winter in the area.

A large flock of around thirty tree sparrows were seen feeding on one block of wild bird seed mix and two of the blocks were sheltering coveys of grey partridge last autumn.

The wild bird seed mix plots are also magnets for hundreds of invertebrates including bees and butterflies.

The floristically enhanced margins will plug the final gap in farmland bird requirements by ensuring that there are insect-rich foraging areas.

Case Study: Skylark Plots

Author: Ian Dillon
Farm: Grange Farm, Cambridgeshire

Aims:

We include two skylark plots per hectare in all winter cereal fields on the farm as an easy means of supporting skylark numbers on the farm.

Management:

In 2009, we trialled spraying out the plots, and found that they worked successfully for skylarks provided that they were sprayed before the end of December. From 2013 this will be the preferred way of creating them, as our contractor has changed to an 18m drill and is less able to create plots when drilling. It also means that the plots are exactly 4m x 4m and so we are taking less land out of production. The plots are sprayed out using a 36m boom sprayer which is pre-programmed to spray out the plots at specified locations within the fields.

Achievements:

The plots work extremely well for us, increasing skylark territories from 10 in 2000 to 43 in 2012. We have good crop yields (9 t/ha for winter wheat and 3.2/ha for oilseed rape), having been doing skylark plots for 12 years now.

Skylark numbers have increased by over 400% on the farm in the last 13 years, against a backdrop of continued decline in the East of England as a whole. Monitoring nesting success in the first three years of using skylark plots showed that the number of nesting pairs in fields with plots increased and the number of chicks that each pair rears also increased.