Jonathan Leake gives an overview of his project and early results.

1. Prof. Jonathan Leake
Prof. Duncan Cameron
Prof. Rob Freckleton
Prof. Mike Burrell
Prof. Steve Banwart
Dr Dylan Childs
Dr Jill Edmondson
Ruth Wade
Prof. Les Firbank
Prof. Joe Holden
Dr Pippa Chapman
Dr Richard Grayson
Prof. Mark Hodson
Dr Thorunn Helgason
SoilBioHedge
Harnessing hedgerow soil biodiversity for
restoration of arable soil quality and resilience
to climatic extremes and land use changes.
Dr Lisa Norton, Dr Alastair Leake,
Dr Nicola Hinton, Dr Matthew Shepherd,
Dr Derek Pedley, Dr Emma Sherlock,
Dr Wendy Seal
Peter Burgis
Oliver Pilbeam
Harnessing fundamental biological and ecosystem science
to create more resilient and sustainable farming systems

2. Wood-to-Hedge-to-Field
Leeds University Farm
> 20 years continuous arable cultivation
60% of years growing winter wheat.
Ewan Marshall-Harries
MBiolSci project 2013

3. Wood Hedge 2 m 32 mGrassy strip
margin
Conventional Arable Field
Wood-To-Field bioassay of wheat ~70%
Ewan Marshall-Harries
MBiolSci project 2013

4. Hedge
2 m 32 mGrassy strip
margin
Conventional Arable Field

5. Growing crops in arable land that is conventionally tilled and fertilized every
year for decades has depleted soil organic carbon, destroyed soil macro-
aggregates, degraded soil water-and nutrient-holding capacity, and impaired
the functioning of mycorrhizal fungi that help maintain soil structure and SOC.
33% decline in water-
holding capacity
> 50% loss

6. Preliminary results
Tiffany Aslam Effects of arable farming on soil fauna
0
10
20
30
40
50
60
70
80
90
Hedgerow
Boundary
1m
2m
4m
8m
16m
32m
Enchytraeidabundance0
2
4
6
8
10
12
14
16
Hedgerow
Boundary
1m 2m 4m 8m
16m
32m
Earthwormabundance
Earthworms
* Effect of distance when data grouped (‘margin’
(hedgerow, boundary); ‘field’ (1-32m) p = 0.035
Enchytraeid worms
** Effect of distance p = 0.001
* Effect of crop legacy p = 0.034
(OSR < VP < WW)

7. Oniscus asellus a common woodlouse
has18,464 records whereas the most common
earthworm A. caliginosa has only 584 records
Earthworms- in the UK amongst the least recorded species.

8. Mean per sample
6.2
7.6
3.4
3.6
3.6
Mummey et al., (2006)

9. Modern agriculture severely reduces AM fungal diversity compared to woodland
No. of samples
in each Genus
Arable
Glomus
Scutellospora
Acaulospora
42 98
97 1
15 1
(Helgason et al., 1998)

10. Do hedgerows and field margins preserve important functional soil biodiversity?
Can we harness this to restore degraded soil structure and function in arable fields?
UK average field size =12 ha (400m x 300m);
960,000 km of field edges, 500,000 km hedgerow.
Earthworm and / or mycorrhiza colonization at
2.5-15 m per year into new leys would cover
8-48% of a 12 ha field area in 3 years.
After decades of research on soil biodiversity, the iconic hedgerow component of the British
farm landscape, remains unstudied as a potential biodiversity refugia for AM fungi, and
earthworms both of which are vital engineers of soil quality but depleted by arable farming.
Countryside Survey
Hypothesis:
Leys that connect to hedgerows and
grassy unploughed margins of arable
fields enable key ecosystem-
bioengineers (earthworms and
mycorrhizal fungi) to colonise from
these refugia thereby increasing the rate
of restoration of soil quality compared
to leys unconnected to field margins.
Benefits from these soil-organism
interactions include increases in water-
stable macroaggregates, water holding
capacity, infiltration rates, SOC storage,
resilience to drought and excess water,
and yields of subsequent crops.

11. Research Objectives
1. Determine, for the first time, the importance of landscape connectivity from
hedgerows to arable fields via ryegrass-clover leys in restoring functional
biodiversity, soil quality (macroaggregates, carbon storage, hydrological function)
and resilience to drought and excess rainfall in arable farming.
SoilBioHedge
2. Deliver an integrated and predictive understanding of the mechanisms by which soil
biota and soil functions recover from impacts of conventional arable farming and
extreme climatic events- combining metabolomic and metagenomic analyses to
resolve the chemicals and communities of organisms involved in macroaggregate
formation.
3. Determine the spatial and temporal scales over which recovery occurs with particular
focus on the role of dispersal of the ecosystem bioengineers - earthworms and
mycorrhizal fungi - from hedgerow and field margin reservoirs to leys that promote soil
quality restoration, macroaggregate formation and improved crop performance.
4. Establish an integrative and predictive spatial-temporal model of soil quality change
at field-to-landscape-scale integrating the role of dispersal of hedgerow and field
margin biodiversity into arable land resulting from land use and management
change involving grass-clover leys and reduced tillage.

12. i) Hedge-to-Field Experiments
Determine spatial / temporal changes in soil structure, functioning and
biodiversity (hydrology, nitrate leaching, metagenomics, metabolomics, AM
and earthworm populations):
2. Along grass-to-arable strips sown with winter wheat under conventional
tillage and minimal tillage.
SoilBioHedge
1 2 3 4 5 6
1 2 3 4 5 6 7 8 9
1. Along arable-to-ley strips connected or disconnected to the field
margin, and across a field converted to ley in 2012.

13. Permanent
pasture
Permanent
pasture
Arable to
pasture
Pasture
to arable
Arable
Arable
i) Hedge-to-Field Experiments

14. Height av. 3m (1.8m – 4.8m)
Width av. 1m (28cm – 131cm)
Hedges are made up of 12 species
Dominant species -
60% Hawthorn (0-100%)
20% Elder (0-60%)
10% Holly (0-50%)
<10% Hazel (0-20%)
<10% Dog rose (0-20%)
<10% Dogwood (0-20%)
Other species present -
Black thorn, Red Alder, Acer, Ash, Spindle, Pear
Hedgerow characteristics
Ruth Wade

15. Dog rose
Rosa canina
White bryony
Bryony dioica
Holly
Ilex aquifolium
Elder
Sambucas nigra
Galium aparine
Bramble
Rubus
Spindle
Euonymus europaeus
Hawthorn
Crataegus spp
Field bindweed
Convolvulus
arvensis
Dogwood
Cornus sanguinea
Hazel
Corylus
Black bryony
Tamus communis
Nettle
Urtica dioica
Pear
Pryrus
Thistle
Cirsium vulgare

16. Measurement Good structural
condition
Measured hedges at
Spen Farm
Height >1m av. 3m
Width >1.5m av. 1m
Vertical gappiness <10% Av. <20%
Gaps No gaps >5m 1 gap of >5m
Non-native species cover >10% <10%
Base height of canopy <0.5m Av. 65cm
Distance between centre of hedge
and disturbed ground
>2m Av. 2m
Width of perennial vegetation 1m Av. 1m
Av. 3.7 woody species per 30m section of hedge in Great Britain
Av. 3.1 woody species in measured hedges at Spen Farm
31% of ‘managed’ hedges were in good structural condition in Great Britain 2007.
Only 10% of ‘managed’ hedges on arable land were in both good structural condition and
had appropriately managed margins in Great Britain 2007.
(Countryside Survey, 2007)

17. Prof. Mark Hodson
Baseline Earthworm
survey in spring 2015
6 earthworm species
N=3 N=3 N=18
Allolobophora chlorotica
Aporrectodea rosea
Lumbricus castaneus
Eisenia fetida
Aporrectodea longa
Lumbricus terrestris
Arable Field
Hedge Margin Field
Epigeic
Endogeic
Anecic

18. Control (field)
Connected Ley
Unconnected Ley
Example layout of ley strips
and control areas of the field
No-Spray areas -
1.2 m deep 13 m long stainless
steel mesh curtain to bedrock
Ground protection mats
for tramlines

19. Schematic diagram of Poplar Field
Poplars
Control
(field)
Connected
Ley
Unconnected
Ley
No-Spray areas -

20. Penetrometer resistance before and after ploughingDr Richard Grayson
Field “tramline”
Connected leyUnconnected ley

21. Soil moisture contentDr Richard Grayson
Wheat field control
Connected ley
unconnected ley

22. In–field weather stations and sensors
Automated soil moisture and temperature
measurements, rainfall, air temperature, solar
radiation, windspeed.

23. >250 µm
>250 µm
Rebecca Crabtree Unpublished MBiolSci project
supervised by JR Leake 2014

24. Soil bulk density coring and SOC
Rhizon samplers for N leaching

25. Ongoing work:
Soil aggregation
Soil organic matter in different aggregate sizes
Soil aggregate metabolomics and metagenomics
Mycorrhizal community analyses
Soil microbial communities
Soil hydrology, faunal macropores
Soil solution nitrogen

26. ii) Landscape-Scale Hedge-to-Field Transects
Determine spatio-temporal variation in soil quality, biodiversity and ecosystem
engineers in pairs of long-term arable fields and adjacent fields converted from
arable-to-pasture over two time periods (1-3 & >3 years) in our existing networks
of over 100 arable farms across England that provide a range of soil types, and
conventional, organic, and minimal tillage management (n=6 reps; 54 total).
SoilBioHedge
iii) Field-to-Landscape Scale Modelling (structural equation modelling)
Establish an integrative and predictive spatiotemporal mathematical model of soil
quality change at field-to-landscape-scale, including the role of dispersal of
hedgerow and field margin biodiversity into arable land resulting from land use and
management change involving leys.
The model will use existing Countryside Survey datasets on hedgerow abundance
per km2, and national digital soil map data and integrate them with mechanistic
understanding of SOC change and soil aggregation through the synergistic actions
of roots, AM, and earthworms from our experiments (i) and landscape-scale
transect observations (ii).
Mesocosm studies of monoliths from the field exposed to simulated
drought and flooding to establish effects on soil and crop resilience.

27. Anticipated research outcomes
1. Deliver an integrated and predictive understanding of the mechanisms by which
key ecosystem engineer organisms (grasses, AM, earthworms) interact to enable
soil quality to recover from impacts of conventional arable farming and improve
soil and crop resilience to extreme weather (drought, excess rain).
2. Provide the first comprehensive assessment of hedgerows and field margins as
biodiversity refugia for earthworms and mycorrhizal fungi.
3. Provide the first detailed assessment of rates of biodiversity dispersal from
hedge-to-field and the role of landscape connectivity, soil type and land
management (conventional arable, organic arable, reduced tillage and inclusion
of leys in rotations) on these rates.
4. Develop a web-based software application tool to guide land managers in the
optimal use of midfield strips or whole field leys for soil quality restoration in
arable fields under different kinds of management and soil types to facilitate
early translation of the research findings to field applications to improve UK soil
quality and harness hedgerow and field margin biodiversity.
SoilBioHedge

28. Acknowledgements:
Funders and helpers
Martin Lappage
Peter Burgis
David Jones
Ewan Marshall-Harries
Dr Lisa Norton, Dr Alastair Leake,
Dr Nicola Hinton, Dr Matthew Shepherd,
Dr Derek Pedley, Dr Emma Sherlock,
Dr Wendy Seal
Peter Burgis
Oliver Pilbeam

30. “A macropore volume of 0.23–2% of total soil volume accounted for 74–100% of total
water flow (Alaoui & Helbling 2006), while Lin et al. (1996) reported that 10% of pores
>0.06 mm contributed about 89% of total water flow”.
Work conducted at Leeds University farm