Wednesday, 6 December 2017

Sustainable Intensification - the foundation is laid

The Allerton Project has played a major role in Defra's Sustainable Intensification research Platform (SIP) over the past three years as one of the five research and demonstration farms in the SIP network. The wider SIP consortium has involved around thirty partners, and last week, most of us attended a three day conference to present our results, share lessons learnt, and discuss options for the future.  The aim of the SIP was always to establish a network of farms and associated research partners as a foundation for continuing collaboration on research into management practices which address economic, environmental and social objectives in agriculture.  The need for such a network is greater now than it has ever been.

Nigel Kendall (Nottingham Uni.) shares research results with visiting farmers
For us at Loddington, the SIP enabled us to carry out our first research into grass and livestock systems.  As a result of the research carried out by Nottingham University School of Veterinary Science, we now have a better understanding of how availability of trace elements such as selenium and cobalt vary spatially between fields and seasonally through the spring and summer, and how sheep respond to these changes.  Such an understanding is important to our ability to integrate livestock and arable systems, bringing grass leys into the rotation so that they perform optimally for both arable and livestock interests, while also delivering for the environment through reduced flood risk, improved soil structure and water quality, and benefits to biodiversity. A summary of this work is available here.  The collaboration with Nottingham University is one we are continuing, with further work already being undertaken on grass and livestock systems. 

The SIP has also enabled us to carry out research into the potential economic and envirommental benefits of cover crops, and into issues associated with landuse change at the catchment scale.  Cover crops are increasingly adopted on lighter soils and in southern England where they are valued by farmers for the benefits they bring to soil structure, organic matter and nutrient cycling, and subsequently to the following cash crop.  On clay soils further north though, the benefits are less clear.  Growing conditions mean that harvests are later and soil conditions are cooler and often wetter when cover crops are drilled, resulting in poorer establishment and associated benefits.  We were able to explore these issues and I will report on this another time, but you can download a summary here.

Our catchment scale work within the SIP was built into our existing Water Friendly Farming experiment and involved using the grass weed herbicide propyzamide as a focus for discussing with farmers a wider range of ecosystem services associated with landscape scale soil and water management.  Both the plot scale cover crops research and landscape scale work on propyzamide are centred around soil as the key natural capital asset for any farm business.

Throughout, we are aiming to develop management practices which benefit both the farm business and the environment, optimising the use of natural resources to achieve this.  Terms such as 'sustainable intensification', 'ecosystem services' and 'natural capital' are commonly used in discussing this broad issue, but each represents a form of jargon that sits uncomfortably with many people.  This is especially so when these terms are promoted with doctrinal zeal which can be confusing and offputting.  It is almost as though such language is used to distance the speaker from the listener - more to instill authority than understanding.

But these terms do have an important role in furthering our understanding, not least through the limitations that each of them has.  As an apparent oxymoron, 'sustainable intensification' does this well, highlighting the tension between maximising production now and ensuring production is maintained into the future through a healthy environment, and pointing the way towards an approach in which both can be optimised.  'Ecosystem services' emphasises the need to improve our understanding of the environmental trade-offs underlying, not just production but multiple other benefits to society, but also reveals the need to recognise those aspects of our environment from which there is no obvious or immediate benefit to society. While 'natural capital' highlights the need to value this broad range of natural resources, it also highlights the limitations associated with making that value purely economic, revealing our lack of knowledge to make that possible, even when it might be desirable.

Such considerations can guide future research to fill these knowledge gaps, but we need to leave the jargon behind when it comes to translating those research findings into guidance for practical management.  Knowledge exchange has been a central part of the SIP, as it has for the Allerton Project throughout the past quarter century.  It is that interaction between academics, the research and demonstration farm network, and a wide range of agricultural professionals which has given the SIP its strength.  The foundation is laid.  There is now some building to do.

Monday, 4 September 2017

Multiple resources and a common vision

The Welland Valley Partnership was one of the first to be set up under Defra's Catchment Based Approach (CaBA) initiative in 2013.  The partnership is led by the Welland Rivers Trust with support from the Environment Agency, and also includes local authorities, National Farmers Union, Anglian Water and others, including ourselves.  The partnership's Resource Protection Group (RPG) includes these and other interests and aims to identify common ground between the often disperate interests of the partners and to guide and support local farmers to adopt management practices that improve the river.

But the Resource Protection Group is not concerned only with water as a resource. Soil, nutrients, and even pesticides which cause problems in water are also resources that require stewardship and wise use in order to achieve profitable farm businesses, as well as improved water quality and enhanced aquatic biodiversity.  The common ground is not hard to find.  Achieving common objectives is more challenging.

That is where the other resource comes into play - knowledge.  That includes the scientific knowledge that the Allerton Project accumulates by conducting research at field, farm and landscape scales, but it also includes the knowledge that farmers have about their land at a similar range of scales. 

Within the Welland RPG there is a balance between practical and academic expertise, spread across the spheres of water policy, catchment ecology, drinking water supply, agri-environmental advice delivery, soil science, agronomy, agricultural policy and practical farming. We have not fallen out yet!  That is not to say that we duck the difficult issues where conflicting interests create challenges, but there is a genuine desire to concentrate on the benefits to us all by focusing on the synergies between land and water management that will meet the needs of our children in future, as well as ourselves right now.

We don't have all the answers, and not everything we do goes as we might expect it to, but that is the nature of a pioneering initiative.  By working closely with the local farming community, and drawing on the latest results from our research, and all the expertise within the group, we are well placed to achieve those common objectives.  And through the Allerton Project's ongoing programme of knowledge exchange activities, we can share the lessons learnt, the good and the bad, with land and water managers from across the country so that the benefits of our work reach far beyond the river Welland.

Monday, 24 July 2017

The nature of landscapes

The wildlife present in any given landscape is determined by the characteristics of that landscape, but what are the characteristics that are most influential, especially for farmland species where the conflict between profitable food production and wildife conservation has played out most forcefully over the past half century or so?  These influences could be types of crops or the amount of semi-natural habitats, or the diversity of different crops and semi-natural habitats, or the complexity of the spatial arrangement of those crops and semi-natural habitats across the landscape.   Inevitably, different species are dependent on cropped or semi-natural habitats to differing extents, but the diversity or spatial arrangement may play an additional role.

Landscape diversity (left) and complexity (right)
We know that some bird species are associated with woodland, others with open fields, and still more use a combination of open fields and woodland or hedges.  Our monitoring at Loddington also tells us that different bird species are associated with different crops, with linnets and reed buntings using oilseed rape, and tree sparrows using field beans for example.  How crops are managed is another influence.  Low input crops support a greater abundance of invertebrate food for breeding birds than intensively managed crops for example. Twenty years ago, our research at Loddington showed that yellowhammers gathering food for their young used different crops at different times during the breeding season.  They had a foraging range of up to 300 metres, so both crop diversity and spatial arrangement of habitats would influence their access to suitable foraging sites.  
Fallow land with Holm Oaks in the study area
In a recently published paper, we explored the influences of landscape characteristics on bird communities in an agricultural area of southern Portugal.  Modelling used bird survey data from 1995-1997, and a subsequent period (2010-2012) in which changes to landscape characteristics had occurred as a result of Common Agricultural Policy reform.  For both farmland species, and rarer species that are characteristic of open steppe conditions, the heterogeneity of natural habitats had some positive influence, and for farmland species, the amount of edge had a positive effect.  However, for the steppe birds, the greatest positive influence was the area of rain-fed arable crops and pasture.

These results suggest that, while structural characteristics of the landscape have an influence on breeding bird communities, the land that is used for food production can have a greater influence for some species if managed sympathetically.   Southern Portugal is not the same as the UK, but this paper supports the suggestion that we need to consider both the composition of the landscape - the crops we grow and the way we grow them - as well as landscape heterogeneity to meet the needs of farmland wildlife. 

This is an approach that we are taking at Loddington, where we have increased habitat diversity and complexity by introducing new habitats through our Environmental Stewardship agreement, but have also increased the diversity of cropped land by extending the arable rotation to include more crops.  To some extent this change is driven by the need to manage competetive grass weeds, but this approach makes the practical management of the rotation more complicated, demands a greater knowledge base, and requires greater storage capacity for the different harvested crops for example. In the past, we have increased the complexity of the spatial crop distribution across the farm, as well as the diversity, but this proved to be a step too far in terms of the economic cost to the business.

We also modify the management of our crops, not least by the selective use of pesticides to minimise negative ecological impacts on pollinating insects, invertebrate predators of crop pests, and the invertebrates that provide food for farmland birds.  Such an approach also requires commitment and knowledge and complicates farm management decisions in what is already an economically challenging world.  The global market for crops pays little heed to the requirements of wildlife, or farmers wishing to conserve it.  Similarly, our move, over a number of years, towards a no-till system of crop establishment, stabilises soil conditions, contributing to better soil function, with potential benefits to terrestrial and aquatic wildlife, but it is not without its challenges and economic costs along the way.

Modifying crop management, increasing crop diversity, and increasing landscape complexity are all changes that are likely to benefit wildlife and landscape in the UK as much as in southern Portugal, but the farming systems and approaches to achieve this are very different.  That is something to consider between now and March 2019.

Wednesday, 21 June 2017

The first 25 years of the Allerton Project

This month we celebrate our first quarter century of research and educational activities at Loddington.  Over the twenty-five years, the Allerton Project has become a byword for practical evidence-based information on a wide range of agri-environmental issues and it is a real privilege to have played an active part in the project for the whole of that time.  On the night of 24 February 1992, our first data were collected from the farm when I ventured north from Dorset to count hares at Loddington.  We still monitor hare numbers on the farm, as well as gamebirds and songbirds, using the same methods that we used twenty-five years ago, creating a consistent and valuable long-term dataset.

Examples of how our research results have fed into policy and practice are numerous. In the early years we helped to inform guidance on set-aside management to improve skylark nesting success and carried out research on grass margins which contributed to the development of one of the most widely adopted agri-environment scheme options. A MAFF contract in the late 1990s enabled us to develop wild bird seed mixtures as an agri-environment scheme option.  Later, we were able to use our long-term monitoring of bird numbers at Loddington to support the case for the provision of seed food in winter to improve the late winter survival and breeding numbers of farmland birds.

Intensive monitoring of the nesting success of songbirds has contributed enormously to our improved understanding of the interaction of habitat and predation pressure on songbird nesting success and subsequent breeding abundance.  As a result of the management system implemented at Loddington, songbird numbers are twice as high now as they were at the start of the project.

Our research extends beyond our own farm at Loddington, especially in terms of catchment management.  A decade ago, we highlighted the impact of rural septic tanks on water quality and aquatic life, and more recently have done the same for rural sewage treatment works through our Water Friendly Farming project.  A partnership with the Freshwater Habitats Trust, this project has become a national focal point for issues relating to the management of agricultral catchments, including nutrients, pesticides and sediment in water, and the implications of land management for downstream flood risk. The combination of field and plot-scale research at Loddington and landscape scale research in Water Friendly Farming enabled us to become one of just three research and demonstration farms linked to landscape scale projects in Defra's Sustainable Intensification research Platform (SIP).

SIP study site leads outside the Allerton Project eco-build visitor centre which receives several thousand visitors each year

Highly relevant to our objectives for improved water quality, managing flood risk, and reducing our contribution to climate change, as well as for economically viable food production, is our research on soil management during a period in which the farm has moved from a plough-based system to direct drilling.  Defra and EU funding has enabled us to explore the potential of cover crops, reduced tillage, in-field barriers and field edge detention ponds.  As a result, we now have a rapidly developing understanding of soil compaction, organic matter, and the important role that below-ground life plays in maintaining soil function to meet both economic and environmental objectives.  While our focus has mainly been on arable cropping, we have recently introduced research on livestock systems and agroforestry.

Our Ecologist, John Szczur has contributed to the Allerton Project's research for the full twenty-five years, but over that time we have also worked with numerous research partners.  Indeed, one of the strengths of the Allerton Project must be our long record of collaborating on research with a wide range of partners across Europe, from academia, NGOs and industry, and our active involvement of the local farming community.  We have also benefited from the many MSc and PhD students who have worked with us over the years.

We have a wealth of knowledge to share.  Last year nearly four thousand people came through our eco-build visitor centre to learn about our research results, how they might be applied on farm, and to the development and implementation of agri-environmental policies.  Our role in this is more important now than ever, as we prepare for life outside the EU.

We have recently updated our report on the Allerton Project's activities, 'Fields for the Future' and you can download a pdf here.  Also, look out for my article in the August issue of British Wildlife, and for further updates on individual projects on this blog over the coming months. 

Wednesday, 15 February 2017

Welland Arable Business Group

The Agriculture and Horticulture Development Board (AHDB) runs a network of Arable Business Groups across the country, enabling farmers from the same area to benchmark the economic performance of their cropping against each other, and against regional and national averages.  It's a great initiative that stimulates discussion within the group about how we each approach our cropping systems.  It is an opportunity for us to learn from each other, as well as from AHDB expertise, and from invited speakers. 

The Welland Arable Business Group was formed in 2015.  Its members have a wide range of business types including various forms of tenure, a range of farm sizes, and some representation of livestock in the predominently arable systems. 

Economic benchmarking stimulates discussion about the dependence of our businesses on the environment
Low crop prices and increasing input costs, coupled with the impending but unkown changes associated with Brexit, mean that profitability is elusive and the future, uncertain. Add to that the vagaries of the weather and exchange rates and maintaining a viable business becomes even more challenging.  This certainly focuses the mind on reducing input costs and making the most of existing assets, but at the same time, makes investment in new equipment and strategies difficult.

Soil is the most fundamental resource of most farm businesses and one of the messages to come out of our discussions within the group is that we need to improve our management of it.  The drive for ever larger machinery, combined with more frequent intense winter rains, and a decline in soil organic matter, all contribute to deteriorating soil conditions and reduce our capacity for both economic and environmental sustainability.
Soil Organic Matter (%) on farms in the upper Welland river basin
Loss of soil organic matter is something that group members have identified as being of concern, and we have been able to help by carrying out surveys of organic matter across farms in the upper Welland.  This provides a baseline against which individual farms can evaluate any changes they make in their soil management.  Most are currently well below the 5% considered to be desirable for effective soil function in terms of crop rooting capacity, nutrient uptake and summer moisture retention.

Our new EU funded SoilCare research project provides an opportunity for us to explore, with local farmers, new approaches to soil management that could help to improve farm profitability, while also delivering public benefits such as improved water quality, and reduced flood risk, all work that links neatly with our other ongoing research projects.
Members taking part in the prioritisation process for soil management research

Group members are not passive recipients of the research results, but have an active role from the start.  In fact, it is the farmers who are setting the research agenda by identifying and prioritising the areas of greatest relevance and interest to their businesses.  Farmers will continue to be actively engaged in the research as it develops.  This approach ensures that the research we carry out as the UK site in this European project will also be relevant to other farmers across much of lowland England. 

Tuesday, 27 December 2016

A flood of interest

Following hard on the heels of the previous record-breaking year, the close of 2016 marks the end of another warmest-year-on-record.  A warming climate is associated with greater frequency of intense storm events and flooding in the UK.  Climate change research back in the 1980s highlighted this association, and warned of rising sea levels and increasing frequency of flood events across much of the world. 

Thirty years ago, the UN's 1987 Brundtland Report brought the results of that research more fully into the public domain.  It highlighted the need for mitigation to reduce emissions of carbon dioxide and other greenhouse gases, and for adaptation to inevitable short-term change. Following two decades of limited activity, the UK's Stern Report back in 2006 provided evidence that the benefits to the UK of strong, early action would considerably outweigh the costs involved.  The earlier effective action is taken, the less costly it will be.

Sediment-laden flood water in a central section of the Eye Brook tributary of the river Welland in 2016

Flooding across the UK since then is consistent with climate change researchers' projections, and the UK Committee on Climate Change identifies flooding as currently the greatest risk associated with climate change. Insurance companies are taking the issue seriously as some properties become uninsurable and the risk associated with others becomes uncertain.  'Building resilience' is an increasing refrain from insurers, while the Bank of England expresses concern about financial instability associated with climate change.

Within our Water Friendly Farming project, we are investigating options for adapting to current flood risk trends by introducing permeable dams and supporting farmers in their efforts to improve soil management to attenuate flood peaks.  As well as potentially reducing flood risk downstream, better soil management can also reduce the effects on crop performance of water-logging, compaction and grass weed competition associated with a combination of heavy machinery and intense rainfall. 

Our continuing monitoring of flow at the base of each of the three study catchments will enable us to document actual change in due course.  We will be modeling the implications of our management on downstream water quality, sedimentation and flood risk under a range of rainfall scenarios.  Initial modeling results suggest that the management we are adopting may be better able to reduce the impacts of regular storm events than some of the more extreme ones that we are starting to experience more frequently than in the past.

The danger is that, as we focus on our response to immediate problems, we continue to neglect the increasingly urgent need for mitigation of longer term climate change.  In 2016, the UK government announced new targets for carbon emissions reduction by 2030 and became the 111th country to ratify the Paris Climate Agreement, signalling new national policy for climate change mitigation. This is one to watch as we enter 2017.

Within the Allerton Project, we contribute towards mitigation by adopting renewable energy and effective insulation, home-working and teleconferences, minimising flying and supporting local food producers.  But we need to do much more, as a society and as individuals, to mitigate climate change rather than just adapting to the consequences of it.  Recent American research suggests that the next thirty years may not be as kind to us as the previous thirty have been.  Our New Year's resolutions seem obvious enough.

Wednesday, 7 December 2016

Robin reliance

It's the time of year when we bring bits of tree into the house and send each other pictures of robins. Robins have featured on Christmas cards since Victorian times and have become as integrated into our mid-winter festivities as holly and mistletoe.  Even the technological advances of recent decades have not totally eclipsed our long evolutionary psychological integration with nature.

Robins are one of our most widespread and abundant species, occuring in woodland, on farms, and in urban gardens.  As a confiding and adaptable bird, the robin is a species which is much loved by a large proportion of people.  This is a species which has a strong cultural value.

Robin territory numbers at Loddington
Robins have fared well at Loddington.  Breeding numbers doubled between 1992 and 2001 during which time we carried out a combination of habitat improvement, legal predator control and winter feeding.  Numbers were 24% lower in 2006 in the absence of predator control.  In this, robins follow the trend set by species such as blackbird and spotted flycatcher whose nesting success and breeding numbers are influenced by the control of nest predators.  

Robin numbers were 56% lower in 2010 in the absence of winter feeding as well as predator control.  Robins are regular visitors to garden bird tables, and have also frequently been recorded using gamebird feed hoppers on the farm at Loddington.  Our Trailcam records even document robins feeding from hoppers at night.  Those big eyes which are no doubt part of the robin's popular appeal, are put to good use.  With predator control and winter feeding restored at Loddington in recent years, robin numbers are now at their highest level since 1992.

This sort of conservation management system has a cost, and this is met by a combination of private funding and government payments through initiatives such as the Countryside Stewardship scheme.  At times of political and economic uncertainty, searching questions are inevitably asked about expenditure at all levels, from government to individual farms and households.  The moral imperative for wildlife conservation aside, the case for public and private investment in wildlife is strong.

Each Christmas we demonstrate the cultural value we attach to robins, but the importance of this species, and countless others, extends much further.  The evidence for important benefits of wildife to human psychological wellbeing continues to mount.  Wildlife can reduce stress and anxiety, and increase positive mood, self-esteem and resilience, helping to reduce mental health problems which are an enormous and persistent social and economic national burden.  The robin is a seasonal reminder that, at times of political and economic uncertainty, arguably above all others, our wildlife is an asset which we need to recognise and support for our mutual benefit.

Friday, 11 November 2016

Water Friendly Farming project results

We launched our latest report on the Water Friendly Farming project at Westminster earlier in the week.  You can access a copy here.

The report covers the results of intensive data collection across five years, and three headwater catchments totalling around 3,000 hectares.  We weren’t surprised by the large turnout to the launch.  This is a project with exceptional experimental rigour, practical grounding and multiple objectives that are highly relevant to current policy for water management in agricultural catchments. The most notable results are worth summarising here.

Phosphorus concentrations at the base of the two ‘treatment’ catchments and one control catchment have increased during the five-year period.  Although high phosphorus concentrations are often associated with high sediment concentrations during peak winter stream flow, for most of the time, during base flow, high phosphorus concentrations are the result of discharges from sewage treatment works.  The increase may be influenced by the relatively low concentrations associated with high summer flows during 2012, but the fact remains that domestic sources of phosphorus are a major issue in rural catchments.  Both agricultural and domestic sources are difficult and slow to address but our research is improving our understanding of the issues.

Landscape scale aquatic biodiversity, as represented by aquatic and wetland plants, has increased in the two ‘treatment’ catchments in response to the creation of new wetland habitats, while remaining constant in the control catchment where there has been no such management.  This is the first unequivocal demonstration of this process and is extremely encouraging in terms of the potential for landscape scale conservation of aquatic wildlife on farmland more widely.

Modelling of our data suggests that a switch from plough-based crop establishment to a no-till approach could result in an 11% decline in peak flow and associated downstream flooding.  The same change in crop establishment strategy could also result in a 38% reduction in sediment load exported from the catchments under most rainfall conditions.  This would also help to reduce flood risk because of reduced sedimentation of drainage channels in the lower catchment.  We will be exploring to what extent such changes are feasible within the constraints currently expedrienced by farm businesses.

Our research continues. Take a look at the report for more detail, and I'll continue to post updates on this blog periodically.

Friday, 28 October 2016

Hedge management for nesting birds

The British lowland countryside is characterised by a network of hedges, a much valued component of our cultural landscape and a nesting habitat for countless birds.  Together with RSPB partners, we recently published a paper on the effects of hedgerow structure on the nesting success of these birds.  Our previous research at Loddington revealed that controlling crows and magpies had a beneficial effect on nesting success and subsequent breeding numbers of some species, and also that nesting success was influenced by the structure of the habitat in which nests were located.

As management of many hedges has been neglected in recent years, resulting in a more open structure, this could leave nesting birds more susceptible to predation than in the past.  Our monitoring of 399 nests over two years revealed that birds were choosing the denser parts of hedges in which to nest.  Nest survival was higher in hedges that had been cut four years before than in those that had been cut more recently (in the previous year), and nests fared better in mechanically trimmed, stock-proof hedges than in recently laid or neglected leggy ones.

This is encouraging.  While we have shown that the control of crows and magpies can have an important role to play in songbird conservation where landscape characteristics support high numbers of these species, our recent research shows that hedgerow management can also help to improve songbird breeding success on farmland.

Tuesday, 11 October 2016

Farming and flooding - investigating common ground

Payments to farmers are currently under review as a result of our forthcoming departure from the EU.  It will ultimately be up to the UK government to decide what farmers get paid, or more importantly perhaps, what they get paid for.  Leaving aside the production of abundant, affordable and nutritious food, what do UK tax payers expect from farmers in return for their financial support?

Through the life of our EU membership, wildlife conservation has been a primary focus for agri-environment schemes, and this continues to be a major concern for a substantial proportion of the population.  Landscape is another.  An abundant supply of clean drinking water is a fundamental requirement of the population as a whole and becomes increasingly challenging as that population increases, and changes in rainfall patterns influence reservoir storage.  Most recently though, it has been the frequency of major flood events that has risen up the popular and political agenda.

Farmers are also concerned about the increased frequency of intense storms in recent years.  Apart from the flooding of low lying farmland, intense storm events cause water-logging and compaction of soils which, in turn, result in deterioration in soils, increases in weed burdens, reduced crop yields, and increases in input costs.  All of this reduces both farm profitability and the production of our food.  Getting water off the land through improved drainage is an increasing priority for many farmers.

So what can farmers do to reduce, rather than accentuate flood risk downstream?  Over the next five years, we will be addressing this question as part of our research in the Water Friendly Farming project, a landscape scale experiment with the Freshwater Habitats Trust which started in 2012 and involves three headwater catchments. 
Diagramatic representation of headwater ditch or small stream showing the two opportunities for controlling flow during storm events - optimising soil management to improve its buffering capacity, and creating permeable timber dams.

While effective drainage on our clay soils is essential, there is scope to improve the water holding capacity of the soil above the level of the field drains.  Improved soil management that reduces compaction and increases organic matter and biological activity improves conditions for crops, but also increases the capacity of the soil to hold water when it rains. Even greater benefits can arise from reduced soil erosion because of the associated reduction in sedimentation of drainage channels downstream.  This is all very much easier to say than to achieve in practice, but we are providing farmers with whatever support we can to help them achieve this over the coming years.  In doing so, we can draw on our own practical and research experience at Loddington, and on specialist advice from others.

We have already been surveying some fields for soil compaction, organic matter and earthworm abundance, all of which influence both flood risk and crop performance, and sharing this information with farmers.

Recently constructed permeable dam in the Water Friendly Farming project study area
There is also scope for holding back water in ditches and small streams by using permeable dams.  Such dams can often be relatively simple to install and permit water to flow normally uderneath them for most of the time, but hold it back when the water level rises during heavy rain.  Retaining water in headwaters, even if only for a couple of hours, can reduce flood risk downstream.  We have just started installing such dams in one of the two treatment catchments in our Water Friendly Farming study area, using locally sourced timber and a local contractor. 

We are using a combination of hydrological modeling by Colin Brown at York University, on-site observation, and guidance from catchment farmers to inform the siting of the dams.  The objectives are always to maintain base flow, optimise water storage during storms, and avoid impacts on productive land.
Over the coming years, we will continue to provide whatever support we can to help farmers in the study area to improve soil management, and we will install permeable dams where it is feasible and effective to do so.  By continuing to monitor flow at the base of the three study catchments, and comparing these data with data already collected as part of our ongoing research, we will be able to evaluate the effectiveness of this approach in terms of reduced downstream flood risk.  Such data, and our experiences along the way, will help to inform the development of policy that enables farmers to be rewarded for carrying out work on their land which has benefits for people living far beyond the farm boundary.

Sunday, 2 October 2016

Allerton Agroforestry

Identifying and understanding multiple benefits from single management practices has been at the heart of our research activity throughout the life of the Allerton Project.  There are few better examples of such multiple benefits than agro-forestry on marginal land.  A number of research projects across the country have explored its potential, but there has been no widespread adoption, in part because government land use policy has focused on single objectives associated with arable, pasture and forestry, and because of apparent limited application on productive land. Agroforestry systems are more widely accepted and adopted in many other parts of the world and I have been fortunate to conduct research into such systems in Portugal and West Africa, as well as following UK agroforestry research with interest.
Portuguese Montado is the classic agroforestry system with tree densities usually of 30-60/ha and multiple uses including cork and charcoal production, and shooting and wildlife conservation, as well as livestock and arable production.
We now have an opportunity to investigate the merits of agroforestry at Loddington.  A moderately productive pasture field that has been used for rearing lambs for many years has been planted with trees at a range of densities.  While maintaining lamb production from most of the pasture through our collaboration with Launde Farm Foods, the trees bring potential additional benefits. The tree species selected, and the inclusion of shrubs in some places, are specifically intended to improve the area for pheasant shooting. The trees and shrubs also provide a new wildlife habitat.  Through the influence of trees on the soil, we might expect increased carbon sequestration, enhanced soil biology and potential for flood peak attenuation through improved infiltration of water during storms.

The trees have been planted without support from an agri-environment scheme but with help from the Woodland Trust who are also supporting our research.  Two plots are planted with trees at a density of 100/ha to represent a relatively high agroforestry density, and these will be compared with other plots at higher tree densities.  Some are planted at 400/ha to represent the lowest permissible density for open woodland planting with government funding, and others are planted at 1,600/ha, the maximum density that can normally be funded for woodland creation.  Trees will be thinned in due course as part of the normal management of such a plantation, but differences in tree density will be maintained.  We anticipate very different results across this range of tree densities in terms of the trade-offs and synergies between our various economic and environmental objectives.

The next few years provide us with an opportunity to learn much about the management of the plots to meet our multiple objectives, and we will also be gathering data to help inform this process.  Our initial priority is to gather baseline data on grass yield and lamb production, tree canopy area, bird numbers, and soil biology, organic matter, compaction and infiltration. These data will ultimately enable us to make environmental and economic assessments of tree planting on pasture under a range of scenarios, and recommendations for future policy and practice elsewhere.

As the trees develop, we will explore the interactions between a range of objectives such as livestock production, carbon sequestration and flood risk management in relation to different tree planting densities.

Thursday, 29 September 2016

Uncovering cover crops

Cover crops are very much a hot topic at the moment.  They seem to have so much to offer – improved soil structure and organic matter, retained nutrients, erosion limitation, and even blackgrass control.  But not everyone is convinced of their merits.  It’s all very well farmers with light land in the south extolling their virtues, but what of the rest of us?  And in these challenging economic times, do they pay?

We don’t have the answer to all these questions, but we are learning a lot about the potential of cover crops on cold wet Midlands clays through a rigorously designed experiment that has been running for the past year.  The research is part of our contribution to Defra’s Sustainable Intensification research Platform (SIP).  We are still analysing the data, but I can share some interim findings.

We looked at three different mixtures, oats and Phacelia; oats, Phacelia and radishes (oil and tillage); and oats, Phacelia, radishes and legumes (vetch and clovers).  We also had a bare stubble control plot in each of the three fields in which the experiment was replicated.  Our Soil Scientist, Dr Felicity Crotty has been gathering data on soil physical, chemical and biological properties, while our Farm Manager, Phil Jarvis is gathering yield and economic data.

Soil Scientist, Dr Felicity Crotty
Felicity quantified the effect of drilling the cover crops on soil structure in comparison to the bare stubble control which had not been driven over by machinery, and by the end of the winter, the soil structure had visibly improved and compaction was reduced in all the cover crop treatments while the bare stubble control remained unchanged.  The oats, Phacelia and radish mixtures had slightly greater plant cover, but importantly, significantly lower biomass of weeds such as blackgrass.  There were some significant differences between cover crop mixtures in soil biology, specifically surface dwelling earthworms and millipedes, which may have implications for organic matter breakdown and incorporation into the soil.  The radish based mixtures were also associated with the highest yield in the following spring oats crop, and lowest weed biomass, compared to the stubble control plots.  Further analysis, especially of the economic data, will enable us to evaluate these mixtures more fully.

Our interim findings for the first year suggest that cover crops can reduce weed populations and enhance yield through improvements in soil function, but we now need to discover whether such benefits justify the cost incurred by establishing the cover crops in the first place.  Meanwhile, cover crops have been established in a new experiment this autumn, this time looking in more detail at the specific components of the mixtures so that we can understand better the role of each species. 

The spring oats following last year’s cover crops have now been replaced by wheat.  Next year we will assess the yields of that crop in relation to the different cover crop mixtures.  Our aim is to understand the implications of cover crops, not just in terms of immediate costs and benefits, but also as part of a rotation.