Does extended pasture resting after grazing improve soil microbiology and soil health?

Dairy farmers in the south west of England are exploring whether they can improve soil whilst maintaining forage quality when adopting longer resting periods after defoliation.

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Field Lab Timeline

    12/9/2021 12:00:00 AM
  • Co-design workshop/farm visit

    Co-design workshop/farm visit
  • 2/18/2022 12:00:00 AM
  • Trial design meeting

    Trial design meeting
  • 5/14/2022 11:00:00 PM
  • Trial kick off; baseline soil sampling/analysis

    Trial kick off; baseline soil sampling/analysis
  • 9/14/2022 11:00:00 PM
  • Field lab meeting & soil sampling demo

    Field lab meeting & soil sampling demo
  • 9/14/2023 11:00:00 PM
  • Field lab meeting & soil sampling

    Field lab meeting & soil sampling
  • 9/14/2024 11:00:00 PM
  • Field lab meeting & soil sampling

    Field lab meeting & soil sampling
  • 4/14/2025 11:00:00 PM
  • 3-year full soil sampling & analysis

    3-year full soil sampling & analysis
  • 6/14/2025 11:00:00 PM
  • Final report published

    Final report published
  • 7/14/2025 11:00:00 PM
  • Open farm walk

    Open farm walk
  • 7/14/2030 11:00:00 PM
  • Open farm walk

    Open farm walk
For further information hover over the above milestone marks
  • Discussion

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  • Achievements

    October 2022

    Group meeting to discuss progress

    Farmers from three of the trial farms met with coordinator Kate Still and Becky from Farm Carbon Toolkit at Old Burford Farm last week to catch up on the progress of the field lab.
    We first looked at the progress of the trial plots over the grazing season, and the experiences on the different farms. It was agreed that the severe drought over the summer had made for a difficult grazing season, though in general the trial plots performed well.

    • On one farm the control plot was slightly ahead earlier in the season but now there has been some rain it appears that the trial plot has taken over, and they have pretty much levelled out.
    • On one farm the trial plots seemed to run out of steam towards the end of the season, while the control kept growing back, this was potentially due to control being a more diverse sward
    • There was no loss of milk from grazing the trial plots at the end of the season for two of the farmers, though a third reported a slight reduction in yields.
    • There was a feeling that you can get away with moving the mob less on the higher plants.
    • In theory the cows should spend less time grazing the longer grass as they can take larger mouthfuls.
    • Some farmers didn’t achieve the trampling effect in the mob paddocks they were hoping for, perhaps need to stock higher

    Milestone: Field lab meeting & soil sampling

    October 2022

    Group meeting to discuss progress cont. - Soil test results

    Soil Test Results
    The results from the initial soil tests were then discussed, and we were lucky to have Becky Wilson from Farm Carbon Toolkit with us to guide us through the baseline soil data.

    The soils were tested in May/June 22, the full testing will be repeated in Spring 25. The plots have been GPS tagged so the exact same places can be sampled again next year. In general the statistics showed that there was no significant difference between the soil test results, but this was to be expected at this baseline stage of the trial.

    There were some differences which were not statistically significant but which are a good indication of soil improvement during the trial:
    • There were more earthworms in the trial plots, which might be because the soil of the trial plots was more shaded during the summer heat so they did not have to burrow so deep.
    • There is also an improvement in fungi levels in the trial plots which is a good sign, though any increase in fungi levels would usually take longer.

    It is expected that a greater statistical difference will be seen in the next samples: hopefully a further shift from bacteria-dominated soil to higher fungi levels in the trial sites. The next round of soil sampling will include infiltration tests, these were not completed in 2022 due to excessively dry conditions.

    Next year when the triallists will be looking at doing some soil assessments themselves, including worm counts, infiltration, VESS and also they are looking to include a dung beetle count in the trial as this is usually a good sign of soil health.

    All the triallists started with pretty good soils, but because they are so varied the group discussed how to ensure they can produce useful and robust outcomes.


    Milestone: Field lab meeting & soil sampling

    June 2022

    Trial design - data collection

    Data collection in April 2022 (Baseline testing) and comprehensive data collection at the end of three grazing periods year 3 (October 2024) as detailed below. Additional physical soil assessments will be completed in 2023 and 2024 as part of field lab meetings. This soil assessment strategy has been put in place to make best use of the budget and in recognition of the slow change in the chemical and biological characteristics of soils.

    The Farm Carbon Toolkit will undertake assessments on both the control and treatment fields:
    - Soil Organic Matter 0-10cm, 10-30cm, 30-50cm
    - VESS Scoring
    - Infiltration rate
    - Worm count
    - Nutrient analysis
    - Aggregate Stability
    - Bulk density
    - Biological activity using soil my undies protocol

    For more information about the Farm Carbon Toolkit’ soil testing methodology and these tests, visit:

    Additionally using SoilBioLab, soil bacteria and fungi lab tests will be completed for control and treatment fields. Baseline samples will be completed in April 2022. Final testing may be completed in October 2025 at the end of the grazing season, but following review, may be carried on in April 2026 allowing for the resting effect of the winter period.

    Following tests:
    - Moisture Content
    - Active and Total Fungi
    - Active and Total Bacteria
    - Hyphal Diameter
    - Organism Ratios

    Forage analysis

    To understand the impact of changes in soil health and mineral availability there will be the opportunity where farmers can commit to collecting their own forage samples to carry out micro mineral forage analysis twice in the year in the baseline year 1 (2022) and year 3 (2024), with a quadrat being cut pre graze. Standard Forage analysis (NIRS) will be completed by Sciantec.

    Milestone: Trial design meeting

    June 2022

    Trial design - layout

    This trial is looking at both the rest period of the sward (e.g. effect of tall grass), and the incorporation/length of residual as part of grazing strategy as both of these are thought to have a positive effect on soil health. Leaving higher residual allows for continued photosynthesis and root structure, whilst trampling adds nutrients to the soil.

    Trials will take place on six farms over 3 years. Trial protocols are as follows:

    Split a field or choose two similar soil type fields, with similar sward composition. Restrict choice of field to those that haven’t been cultivated within the last 2 years and no cultivation should take place in the study fields for the next 3/5 years to ensure stability of soil.

    Control plot: Manage as routine within the grazing rotation

    Treatment plot:
    - Aim to allow pre graze sward growth to reach a height 30 – 50% taller than in control field, with an aim where suitable, of an entry cover c. 4500 kg/DM per ha
    - Apply a 1/3 eaten, 2/3 residual/trampling approach – with stock removed at a a minimum 7 cm or 2000 – 2500 kg/DM per ha.
    - Apply a stocking rate/land parcel size to meet forage needs of group of cows. Treatment and control fields can be split into multiple grazing cells/paddocks depending on size/forage need of the group of stock. The control and treatment paddocks can be grazed at different points within the grazing rotation as long as the entry and exit sward height of the control field is in line with he “standard” rotation and the entry and exit approach of the treatment field is in line with above.

    Data already being collected by the farmers:
    - Pasture covers (plate meter data) (due to concerns over accuracy of plate meters, especially with diverse leys, farmers will also measure sward height and where possible, cut and weigh a quadrat sample to get accurate kg fresh weight and DM, before the animals go into graze. The forage samples will be taken by the farmers, therefore will only be taken on farms where the tr

    Milestone: Trial design meeting

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