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Devon silvopasture network

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Summary

In this research network, seven farms and a research farm are being supported to design and implement silvopasture systems: planting trees within pasture fields used by livestock.  Three designs are being tested with a mixture of cluster planting, regular spacing and shelterbelts being planted.

This farmer-led project was created as there has been limited research on the impact of silvopasture in the UK. With excitement about agroforestry on the rise, farmers are looking for clear evidence of a potential return on investment in order to justify the significant financial commitment to turn pasture over to silvopasture.

The farm enterprises are currently a mixture of dairy, beef, sheep and arable. Over 12 years, the farmers will monitor tree establishment and factors that may effect this (fencing, wildlife, livestock interactions and the use of decoy rubbing posts and 'sacrificial willow' to distract livestock from protected trees and shrubs).

How it works

Silvopasture is meant to bring the following benefits:

  • Trees provide shelter: Excessively hot, dry, cold, wet or windy conditions can affect grazing conditions, cause stress to the animals which can lead to poor growth in calves and lambs, lower milk production from cows, higher mortality rates in lambs and greater incidents of disease such as fluke, foot rot and mastitis in ewes. 
  • Trees provide additional products: Farmers are looking to improve the sustainability and productivity of their farms but really need clear evidence and an understanding of a potential return on investment in order to justify the significant financial commitment required to turn pasture over to silvopasture. 
  • Trees provide additional nutrition  The shrubs and smaller trees have varied nutritional benefits for the livestock giving them access to minerals, protein and condensed tannins for self-medication.
  • Trees can increase environmental benefits of the farm. Planting trees brings biodiversity (with knock on benefits with various ecosystem services), soil health and carbon capture on the farm.

Trial design

The field lab will work with multiple partners to conduct research across a range of topics, looking at environmental and animal behavioural metrics as well as certain practical management considerations.

The Woodland Trust worked with the farmers to design a planting system to suit their farm, and provided funding to cover the planting and tree protection.  For information on planting designs please see “Three silvopasture designs to suit your farm”.

A fuller description of the trial design and the roles of the different stakeholders can be found in the reports and results section of the field lab page.

What is being measured?  

To really establish the benefits and impact of silvopasture over the 12-year period, a variety of tests will be taken. The wealth of quantifiable data that this field lab will offer will help researchers to better understand the impact of silvopasture, including different designs, on the wider farm system. 

The tests will include: 

  • Surveys in vegetation, soil organic carbon, and insect communities and how trees affect these metrics as they grow.  

  • Looking at sward competition and rates of growth at different stages of tree canopy development  

  • Biodiversity research looking at bats, birds and dung beetles and population as the agroforestry system matures. 

  • Monitoring tree establishment rates and practicalities of looking after the trees – considering factors such as climate, competition, and stock eating the trees.  

  • When the livestock have been introduced, various welfare assessments will also be undertaken.  

Latest updates

The Devon silvopasture network have been working with the BTO to detect bats at some of the silvopasture trial farms.

A survey and sampling protocol was devised that allowed farmers to deploy static acoustic bat detectors over a 7-month survey season to provide baseline data for bats.

A full report (which can be found at the results and reports tab) provides an overview of the survey coverage and main results from 2023. 

During 2023, 30 different locations across the Elston Farm, farming cluster were surveyed. Recording was undertaken on 94 different nights mainly between April and the end of October.

Following validation, the study confirmed the presence of 15 bat species, 2 small mammal species, and 4 species of bush-crickets. Through the project, we have a better understanding now of the status of all species of bats on the farms surveyed.

The full report can be found on the results and reports tab of the field lab webpage.

In September members of the Devon Silvopasture Network spoke at a very well-received session at the Agroforestry Show. You can watch the session here:

Cows and Trees session at the Agroforestry show

Dr Carmen Segura-Quirante updated the group on the baseline soil sampling results which were taken between Dec 2020 and Feb 21:

·       Different protocols and tests have been followed to determine physical (bulk density and texture fractions) and chemical (pH, % SOC and TN) soil properties

·       Bulk density analysis (BD) and chemical analysis were carried out in North Wyke, and texture fractions were provided by an external laboratory from baseline soil subsamples processed at North Wyke

·       Estimated time effort in working hours for the baseline soil study =2000 h. Lab team= 8 people

·       Tests to check the presence/absence of inorganic C (IC) were based on acidified washing procedures of soil subsamples when pH > 6

·       We assume Soil Total Carbon (IC + OC) = Soil Organic C as no evidence of IC was found (pH < 6 in most of the samples and no effervescence when higher pH)

·       The composite sample approach is an accurate method to determine SOC at baseline level. In our case 1 composite sample= 6 samples from the same strata and per depth. To do the composite sample, we took a subsample of each individual sample to keep spare soil in our archives for the future.

·       SOC and TN (%) were determined by standardized and recommended methods to assess changes in SOC (Carlo Erba elemental analyser)

·       SOC stocks were calculated from SOC (%), BD (g/cm3) and soil depth (cm) for 0-10 cm and 10-30 cm soil depths

·       Mean values (% SOC) in the topsoil (0-10 cm) were in the range of values reported in the UK for arable fields and grasslands

The individual results will be sent out to the farmers themselves shortly.

The next samples will be taken within 4 years of the initial samples by Rothamsted.

We have pending to pass the questionnaire about land use and management to them.

Rothamsted research visited the farms in February and March to undertake baseline sampling and will monitor the change of this over the next 12 years to understand whether the integration of trees improves soil organic carbon sequestration and soil structure.

The assessments:

  • Soil organic matter - leaf and root decomposition, root respiration and root fungal/bacterial processes all add organic matter to soils
  • Bulk density - a measure of soil compaction, which influences water availability, plant rooting depth, the availability of plant nutrients and soil microorganism activity

    The samples are being frozen and stored - in total around 1,000 samples have been taken. Samples will be taken at 0-10cm and 30cm. Sampling will next take place at intervals over the next 12 years, with the next soil sampling to take place in 3 years time as changes in soil organic carbon is a slow process.

    The researchers expect that there may be some initial losses in soil carbon from tree planting, but overall this is minimal as soil disturbance associated with digging small holes for the trees is likely to be very low.

    The researchers followed sampling methodology followed UN FAO protocol for measuring, monitoring and reporting on soil organic carbon in agriculture. The protocol can be adapted locally to monitor SOC stocks and stock changes to support management decisions and can be found at: http://www.fao.org/3/cb0509en/cb0509en.pd

Advisors from the Woodland Trust and FWAG visited each farm in autumn 2020 to develop tree planting designs unique to the needs of each farmer. The trees (funded by the Woodland Trust) were planted at the farms throughout February, with some farms involving dozens of local volunteers in the planting.

Three planting designs will be used overall - shelterbelts, regular spaced strips and open-grazed clustered wood pasture. The farms will use one or more of these designs across their fields. The benefits and drawbacks of each design are detailed here. 

For example, regular spaced strips allow machinery access to alleys for cutting silage if farmers wish to manage this as productive grassland throughout the year. However, the prioritisation of grass in this design means the least biodiversity benefits are expected of all three designs.

These research milestones were agreed at the beginning of the field lab: 

Planting designs developed

10th September 2020

Fencing installed

January 2021

Trees planted on farms

February 2022

Baseline soil sampling

March 2021

Baseline biodiversity monitoring

May 2021

Ongoing monitoring

Early summer 2022

Ongoing monitoring

Early summer 2023

Ongoing monitoring

Early summer 2024

Ongoing monitoring

Early summer 2025

Group Coordinator

A portrait of Jon Haines.
Jon Haines

Soil Association

Jon Haines joins the Farming and Land Use team as an Agroforestry Advisor, where he will help individual members with agroforestry technical, marketing, supply chain and networking queries. He brings knowledge and experience of both arboriculture and agriculture. His previous role saw him travel to implement and support farmer projects with herb, spice and tea farmers around the world. He has also helped set up a pioneering community aquaculture project off the coast of St Davids, Pembrokeshire.

Farmers

A portrait of Andy Gray.
Andy Gray

Elston Farm

Devon

A portrait of Sam Bullingham.
Sam Bullingham

Rowden Farm

Devon

A portrait of Hen Curtis.
Hen Curtis

West Elmett Farm

Devon

A portrait of Carolyn Richards.
Carolyn Richards

Ashridge Court

Devon

A portrait of Seb Powell.
Seb Powell

Hill and Coombe Dairy

Devon

A portrait of Henry Andrews.
Henry Andrews

Warson Farm

Devon

Researchers

A portrait of Dr Lindsay Whistance.
Dr Lindsay Whistance

Organic Research Centre

UK

A portrait of Robert Dunn.
Robert Dunn

Rothamsted Research

UK

A portrait of Mel Wright.
Mel Wright

Rothamsted Research

UK