Alternatives to plastic film mulch

Investigating alternatives to plastic mulches

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Field Lab Timeline

    2/13/2020 12:00:00 AM
  • Objectives agreed

    Objectives agreed
  • 3/20/2020 12:00:00 AM
  • Group and methods confirmed

    Group and methods confirmed
  • 4/9/2020 11:00:00 PM
  • Demonstration workshops/ webinars

    Demonstration workshops/ webinars
  • 7/30/2020 11:00:00 PM
  • Application of mulches (depending on crop)

    Application of mulches (depending on crop)
  • 9/14/2020 11:00:00 PM
  • Data Collection & Analysis

    Data Collection & Analysis
  • 3/10/2021 12:00:00 AM
  • End of first year group catch up

    End of first year group catch up
  • 7/30/2021 11:00:00 PM
  • Second year application of mulches

    Second year application of mulches
  • 9/14/2021 11:00:00 PM
  • Second year data collection & analysis

    Second year data collection & analysis
  • 3/30/2022 11:00:00 PM
  • Data Collection & Analysis

    Data Collection & Analysis
  • 3/30/2022 11:00:00 PM
  • Final report published

    Final report published
For further information hover over the above milestone marks
  • Discussion

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  • Achievements

    March 2021

    2021 trials details

    A total of 10 growers will take part in trials in 2021, which includes 6 new sites:

    • A top fruit nursery trialling woodchip and biodegradable film
    • An agricultural college trialling green waste, cardboard, hay and biodegradable film
    • A women's prison trialling cardboard and biodegradable films against current Mypex on veg and fruit
    • A farm-based mental health charity trialling various mulches including green waste, paper, Mypex and biodegradable mulch
    • A top fruit and tea grower in Scotland trialling wool and biodegradable muches
    • A blackcurrant farm trialling living mulch (e.g. white clover) and possibly wool

    Each site will collect data on weeds, yields, costs and qualitative observations. Some are also assessing microbial activity, pest and disease damage, soil nutrients, etc.

    Full details of each trial are in the 'Documents' section attached.

    Milestone: End of first year group catch up

    March 2021

    Reflections - end of year 1 grower meeting

    Grower reflections so far:

    - CAWR trials comparing poplar chips, extruded poplar, willow chip, hay and grass cuttings found that the hay was by far the best at suppressing weeds. They didn’t experience any issues from the hay mulch seeds germinating
    - Loose mulches need to be applied at a high rate
    - A combination of loose mulches may work better. For example, one grower reported a layer of hay with a layer of brown paper underneath worked really well. Something like paper or cardboard to keep the light out underneath another mulch for organic matter additions
    - If using woodchip, the choice of wood important otherwise the plant may experience mineral/nutrient deficiencies
    - It can be difficult to manage biodegradable film and if weed growth cuts through the film, this results in excessive weed growth
    - CAWR found a big range of potentially harmful chemicals in a non-bleached paper manufactured for no-dig organic production. It is not known whether the chemicals leach into the soil or what their effect is

    Milestone: End of first year group catch up

    November 2020

    Update from first year of trials

    The majority of quantitative data from this year has now been collected. This, alongside qualitative information on growers' observations/experiences, suggests:

    • There are range of viable alternatives to plastic - both local and commercially sourced, that can reduce the need for weeding
    • It is not possible to draw conclusions on individual mulches or compare results between farms as a wide range of crops, soils and mulches were trialed. However, most growers reported difficulty with biodegradable mulches tearing and disintegrating or detaching from the bed
    • Unsurprisingly, un-mulched plots performed the worst in terms of yield and weed coverage

    The blackcurrant grower hopes to use woodchip as a mulch as they have access to willow and spruce on farm, though the amount of willow woodchip required to scale this across the farm is a potential barrier. Considerations when using woodchip as a mulch include possible mineral deficiencies (type of wood is important) and irrigation.

    The group are awaiting data from the onion trial at Five Acres Farm.

    The field lab will continue into anther year to allow growers to run trials who had expressed interest but were not able to take part this year. This includes growers interested in looking at wool as a mulch.

    More information on this field lab, including individual grower data and a video of the trial, can be found in the digital field lab journal:

    Milestone: Data Collection & Analysis

    July 2020

    Trial details

    Trials this year are taking place at 5 sites.

    1) Onion trial at a community farm in Warwickshire, recording yields and weed coverage. This site will compare an unweeded plot with no mulch, a weeded plot with no mulch, and plots of either woven polypropylene, polythene, paper or commercial biodegradable films.

    2) Kale trial at a market garden in mid-Wales, recording yields, costs, weed & pest damage. This farm will trial compare biodegradable film to grass cuttings, woodchip and an undersown living mulch.

    3) Blackcurrant bush trial at a commercial farm in Essex, recording growth of new bushes planted into the mulches, the number of dwarf and dead bushes and weed coverage. This farm will trial out biodegradable film and willow woodchip in two sizes compared to a unmulched bare earth.

    4) Organic farm in Leicestershire, comparing cardboard, hay and grass clippings.

    5) Organic community farm in Newcastle-upon-Tyne, comparing woodchip, woven polypropylene and biodegradable film.

    Unfortunately, several growers had to drop out due to the impacts of Covid-19 on, slowing the delivery of mulches, hindering some people's ability to get out on site or have colleague support to run their on-farm trial. These will have the option to commence their trial in the second year of the field lab.

    Milestone: Application of mulches (depending on crop)

    May 2020

    Protocol pack - how to run your own trial

    Instead of physical workshops to help instruct the group on data collection and mulch laying, the researchers and coordinator have created a how-to guide and an instructional videos.

    If you are exploring non-plastic mulches and would like to follow the protocols of this trial, login to download the guide in the 'Documents' section of this page. This includes tips for laying biodegradable mulch.

    Milestone: Demonstration workshops/ webinars

    March 2020

    Group and methods confirmed

    Ten growers have signed up to trialing alternative mulches on a range of crops including brassicas, onions, lettuce, beetroot, spinach, leeks, onions, blackcurrants and young top fruit trees.

    There is also a range of mulches being trialed by the group: Woodchip, grass, cardboard, under-sown mulches, green waste, straw, hay, wood, compost, biodegradable film and paper against the control of black film or woven plastic.

    All of the farmers will collect data on the following parameters:

    - Weeds
    - Yield
    - Qualitative observations
    - Costs

    Many have chosen to also collect data on soil moisture and pest/disease damage, and a few will measure crop development, microbial activity (measured through respiration rate) and soil nutrients.

    Milestone: Group and methods confirmed

    February 2020

    Objectives agreed

    Growers, gardeners, mulch suppliers and researchers met at Garden Organic to agree on the objectives and methods for the trial. There was a wide representation of growers, including (soft fruit) crops; field vegetables; small-scale farms and protected cropping.

    The group discussed the following:

    - The type(s) of mulch to trial - each farm will decide on which mulches they would like to trial, but they include compost, woodchip, starch-based materials, hay and cardboard
    - The size of the trial area - ideally 20-30-metres strips, replicated in several growing spots to generate meaningful data (less for small farms)
    - When the mulches should go down - this depends on the mulch and crop
    - What, data growers can/want to collect - the priorities are weed cover, crop performance and pest damage (measured on a scale of damage), but where possible, the growers would like to also consider soil moisture, and soil health (most likely via a low-cost solution such as a worm count). Cost and time will also be considered in the final results

    Milestone: Objectives agreed

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