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Related Field Labs

No-till with living mulches

This field lab will be investigating the potential for establishing no-till organic/low input arable farming systems using a permanent living mulch understory.

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Field Lab Timeline

    8/31/2019 11:00:00 PM

  • Proposal submitted

    Proposal submitted
    • 2/20/2020 12:00:00 AM

  • Group meeting

    Group meeting
    • 3/19/2020 12:00:00 AM

  • Methods decided

    Methods decided
    • 4/23/2020 11:00:00 PM

  • Clover cover crops drilled

    Clover cover crops drilled
    • 6/24/2020 11:00:00 PM

  • Soil and cash/cover crop tissue analysis

    Soil and cash/cover crop tissue analysis
    • 8/29/2020 11:00:00 PM

  • Cereal harvest, yield and quality analysed

    Cereal harvest, yield and quality analysed
    • 9/23/2020 11:00:00 PM

  • Group meeting

    Group meeting
    • 10/27/2020 12:00:00 AM

  • Drilling of cash crop into living mulch

    Drilling of cash crop into living mulch
    • 11/10/2020 12:00:00 AM

  • Soil and cash/cover crop tissue analysis

    Soil and cash/cover crop tissue analysis
    • 3/30/2021 11:00:00 PM

  • Soil and cash/cover crop tissue analysis

    Soil and cash/cover crop tissue analysis
    • 5/13/2021 11:00:00 PM

  • Interrow mowing

    Interrow mowing
    • 6/1/2021 11:00:00 PM

  • Open farm walk

    Open farm walk
    • 6/16/2021 11:00:00 PM

  • Soil and cash/cover crop tissue analysis

    Soil and cash/cover crop tissue analysis
    • 8/11/2021 11:00:00 PM

  • Harvest yield and quality assessments

    Harvest yield and quality assessments
    • 9/14/2021 11:00:00 PM

  • Autumn establishment trials begin

    Autumn establishment trials begin
    • 12/1/2021 12:00:00 AM

  • Interim results

    Interim results
    • 1/31/2022 12:00:00 AM

  • Results Meeting

    Results Meeting
For further information hover over the above milestone marks
  • Discussion

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  • Achievements

    July 2022

    Results from 2 years of trials - Yields

    YIELD AND YIELD COMPONENTS:

    Grain yield data from the three successfully established organic trials showed a significant and large yield reduction from the living mulch

    Inclusion of a direct drilled control suggests that part (around half) of the yield penalty comes from the no-till system and associated differences including sowing scheme. Competition from the clover appears to account for around half the yield penalty. Direct drilled spacing has wider rows than standard drills, so with similar seed rates, it is not surprising that there were lower plant populations, regardless of the clover mulch. This may explain the approx 20% yield penalty between a standard and a direct drilled system.

    Data on yield components collected in May and June, revealed trends for reduced numbers under the living mulch treatment. Tiller numbers, panicles/m2 and spikelets per panicle were all lower for oat crops and ear length was shorter in the rye crop showing that the clover had offered competition with the cereal crops during yield component formation.

    Yield components reveal timings of competition between the clover and cash crop, and suggest that attention should be focussed on limiting competition over winter and early spring during crop establishment.

    Milestone: Interim results

    July 2022

    Results from 2 years of trials - Weeds

    WEEDS:

    The three trials show a significant and large increase in weed cover in the living mulch - even more in direct drilled. Inclusion of a direct drilled control suggests that the clover did help to control weeds to some extent but this was not significant. The controls were relatively low in weeds from good mechanical control and a “poor” spring season for weed growth.

    Results of the weed cover assessments converted to relative abundance of key functional groups, perennial, annual, monocot and dicot show significant shifts in the relative abundance of the more competitive perennial and monocot groups under the living mulch treatments. This shift took place over only one year of the organic no-till living mulch system and may suggest that the system (at least organically) can only be applied for one or two years before remedial action is required to help control more aggressive weeds.

    Milestone: Interim results

    July 2022

    Results from 2 years of trials - Fertility

    NITROGEN:

    Results of soil sampling in Autumn 2021 following 18 months of the living mulch system show significant increases in the amounts of available nitrogen under the living mulch treatments with over double the kgN/ha compared to the control and almost treble the kgN/ha compared to the direct drilled no-till control. It would appear after 18 months of the new system that nitrogen is beginning to cycle more effectively, especially since paradoxically bare soil during the Autumn often shows higher levels of mineral N as there is no crop uptake, but in the living mulch treatments where there is full clover cover, available nitrogen is still significantly higher.

    Increases in available nitrogen and potassium, and higher microbial activity in autumn could be expected to help crop establishment and early growth of any cereal crop direct drilled at that time of year, with nutrient cycling improving after 18 months of the new system but with a caveat that mechanical damage and defoliation of the clover were required to promote nutrient availability and microbial activity. This result further highlights the importance of mechanical damage of the clover in spring to release nutrient required for cash crop growth and a time of high demand for resources and also points towards the need for selective clover management, through the use of either herbicides or inter-row crimping or mowing equipment.

    Milestone: Interim results

    December 2021

    Interim results

    YIELD:

    • From assessments in the three trials where the living mulch established, there has been a significant yield gap from implementing a no-till + living mulch system, averaging around 60% yield compared to the control (standard farm practice). Results suggest half the yield penalty comes from implementing a no-till system, with the rest due to clover competition. These comparisons were enabled by one site having three treatments: 1) Control; 2) Direct Drilled without clover; 3) Direct drilled + clover living mulch.

    • The farmers can tolerate some yield penalty as there are savings in cultivation costs and reduced seed cost as there is no need to sow annual cover crops, plus there is increased forage for sheep.

    • Two caveats to the yield results are that 1) the mulch was supposed to be predominantly microclover but in practice was more of a standard medium leaf, which provides more competition with the cash crop. Some of the group are now trialing a smaller leaf variety. 2) Minimal intervention was applied to the clover during the growing season. Clover management is also being investigated in the next round of trials.

    SOIL NITROGEN:

    • 18 months since the clover living mulch was drilled, levels of available soil mineral nitrogen are rising, with statistically significant results. In the living mulch plot, available nitrogen is over double that of the control plot (standard farm practice). However, we cannot yet assume it can be a proxy for N fertiliser replacement.


    WEEDS:

    • There have been significant increases in the relative abundance of perennial weeds and grasses under the living mulch system. Mechanical control and ploughing helped to reduce weeds in the control plot.

    OTHER:

    • There is evidence in literature of other long-term benefits of a no-till living mulch system which cannot be addressed in this field lab. This includes soil fertility and biodiversity.

    Milestone: Interim results

    September 2021

    New autumn establishment trials + spring trial update

    Four new farmers have joined as triallists aiming to establish a clover living mulch in the autumn. All trials are using either a trial mix of 70% Jura and 30% Merwi, or 100% Jura (micro clover). Further details:

    Site 1: Two trials, both established with winter wheat. Trial 1: whole field (2ha) trial clover mix looking at whether N inputs reduce. Trial 2: 1ha trial mixed clover vs 1ha micro clover vs a control of no mulch.

    Site 2: Trialling 3ha of mixed clover vs a control of no mulch. Fields will go into beans then wheat.

    Site 3: Interested to try 2ha straight micro leaf vs 2ha of mixed clover. Will sow with wheat.

    Site 4 (James Alexander): Will test autumn establishment of mixed clover vs micro leaf clover, both with a nurse crop of buckwheat, with a view to drilling a spring crop. Also running spring establishment trials as part of the field lab.


    Update on spring trials:

    James Alexander: Will continue with organic trial another year, drilling spring beans into the mulch and controls. Whilst establishment in the organic field has been successful, the second attempt to establish clover in the conventional field has failed.

    Mark Lea: Has terminated two previous trials due to his own rotation and issues with perennial weeds. Set up a new mulch trial in Spring 2021 undersowing spring wheat and including a non-mulch control. Is thinking about testing both heritage winter wheat and winter oats again. From a trial perspective having a second year of winter oats would be valuable and could help inform on management practices for mulch control.

    Jamie Stephens: Has a successfully establish clover mulch established on Spring 2021.

    Milestone: Autumn establishment trials begin

    August 2021

    Learnings from 2nd year - Mark Lea

    Mark Lea, trialing living mulches on his organic farm in Shropshire, shared the changes he'd make in the following years:

    • Try long-straw wheat
    • Graze harder pre-drill
    • Drill a bit earlier (tine and disc drilled rye and oats on 23rd October last year)
    • Graze the mulch in winter to damage the clover, which should hopefully threaten the clover and stimulate it to fix nitrogen
    • Micro-clover only (previously used a mix of medium and small leaf clover)
    • Slightly increase seed rate

    On a practical level, the living mulch setup has worked. The main disadvantages of the system Mark has noticed so far are:

    • Yield penalty (the clover provides too much competition). There are some financial savings (lower cultivation costs, forage value from grazing, potential to remove the fertility building period). "We know we can live with 0.6 tonnes/ha reduction in yield without being any worse off, purely in terms of cost saved... that is before the non-costed benefits like carbon sequestered, improvements to soil heath and structure". They will continue to explore ways to reduce the clover's competitive edge, e.g. interrow mowing

    • Less control over perennial weeds. As an organic farmer, ploughing has kept weeds to a 'reasonable' level, but in these trials, no-till + living mulches has seen a build up in grass weeds, docks and thistles. There may be a need to periodically break the living mulch cover to plough for perennial weed control.

    They tend to run a five year rotation, where one year is a fertility building grass ley with clover + four years combinable crops (inc. a legume). Realistically, Mark thinks he might be able to have 2 x 2 year periods within the four years of cropping that involve a living mulch. Between those, they could break the clover to control the perennials. This setup wouldn't typically be possible without the living mulch - "the whole system of nutrient budgeting could change" if clover is in the ground every year for the cropping period.

    Milestone: Cereal harvest, yield and quality analysed

    May 2021

    2nd year of trials - individual farms

    James Alexander, Oxfordshire: Direct drilled winter oats into the clover in Oct 2020, planted in 20cm-wide rows. Currently the oats on the organic plot are looking better. “The oats stood proud over the clover all winter and those crops grown in the mulch are looking taller, darker and stronger than our farm standard, due to improved nitrogen fixing”.

    Jamie Stephens, Worcestershire: Ploughed in February 2021 to remove the weeds before reseeding the mulch, which didn’t establish in the first year. This will be accompanied by a nursery crop of oats to aid clover establishment.

    A separate plot of medium-leaf clover has been planted to provide extra competition against weeds and to promote sheep grazing throughout the autumn and winter. Sheep grazing over winter should help to limit the clover’s growth if it is outcompeting the cash crop, and in turn stress the clover, which releases nitrogen into the soil. He has also adapted a CTM weedsurfer to interrow the living mulch when grazing would otherwise damage the main crop.

    Clive Bailye, Staffordshire: Reseeded mulch this spring, interrowing it with a barley and wheat crop.

    Mark Lea, Shropshire: Two trials - winter oats and winter rye this year - the clover is doing well but too much competition will result in yield penalty. The clover is providing good control of annual weeds but not perennials. Mark is considering drilling the next crop earlier (i.e. Sep rather than Oct) so that the crop has more time to establish.

    Given the risks of spring drought which has caused several cases of failed clover establishment amongst the trials, the group will look to potentially run complimentary trials on autumn establishment of the clover. Based on indications of high competition from the clover, we discussed that sites without livestock should perhaps sow only smaller white clover variety, whilst sites with livestock that can provide heavy grazing may be more suited to the current mix (70% small-leaf and 30% medium-leaf).

    Milestone: Group meeting

    February 2021

    Results from year 1 - individual farms

    James Alexander, Oxfordshire (conventional and organic trials):

    In spring 2020, James drilled 3ha of clover directly into both an organic and conventional spring barley crop using a Horsch drill. The clover established very well on the organic land, not exceeding more than 7.6cm in height and didn’t cause any issues at harvest. Weeds appear to have also been suppressed. There was a slight increase in barley yield which may have been due to the extra nitrogen supplied by the clover. The conventional trials didn’t establish – they were planted with the same drill on the same day.

    Jamie Stephens, Worcestershire:

    The first year’s mulch didn’t establish, due to drought conditions, which brought a strong emergence of ryegrass and other weeds. The plan is to plough to remove remaining weeds and reseed the mulch this year.

    Clive Bailye, Staffordshire:

    The clover was interrow drilled into a wheat crop over a 4ha area. Very dry conditions (no rain for 90 days straight) meant that none of the clover established. Reseeding mulch in spring 2021.

    Mark Lea, Shropshire:

    The clover was undersown in early May 2020 into spring wheat and winter wheat fields. The following period of very dry weather resulted in poor clover establishment. Stubble was grazed back hard by sheep until late October then new cereals (winter oats and winter rye) were disc and tine drilled (to compare drilling). In the winter rye field, the clover has done very well and the rye is 'okay'. In the winter oats field, both the oats and clover are doing well. Both drilling methods appear to work.

    Milestone: Soil and cash/cover crop tissue analysis

    September 2020

    Initial results: Weed and living mulch cover

    The group met virtually in late September to discuss the initial results from the 7 trials:

    - 4 successful establishments, including 1 late established
    - 3 unsuccessful establishments

    Because of this, the group of triallists falls into two categories:
    1) Successful clover establishment in Spring/Summer. Next phase is drilling cash crop into standing clover
    2) Unsuccessful clover establishment in Spring - needs reseeding

    Potential reasons preventing establishment:
    - Very dry Spring (rainfall in May 2020 was 20% of the 1981-2010 average at the triallists' locations)
    - Hard frost in early May just when clover may have been establishing
    - Season (see below)

    Impact of clover on weed cover:
    - Where clover established well, there is evidence that weeds were suppressed, in particular, perennial weeds and grasses.
    - Late season establishment of clover may not offer enough competition against weeds
    - Whilst it may be less risky to try to establish clover in the Autumn, there will be more competition from weeds. Spring established clover going into a spring crop is favourable as weeds will experience more competition from the cereal crop, clover and a chance for mechanical weeding prior to establishing clover in spring.

    Next steps:
    - Where mulch has established, biomass and N content assessments of the clover, soil sampling at the time of cash crop establishment and monitoring of the cereal crop will continue to take place. The mulch will need to be controlled as much as possible for as long as possible during early growth of the spring crop during early crop growth and development.

    - Where mulch has not established, the farmers that are happy to do so will will make a second attempt to establish the clover in Spring 2021. Some may choose a different mulch mix, e.g. linseed and clover.

    Milestone: Group meeting

    June 2020

    Establishment of mulches

    The farmers discussed establishment of the white clover living mulch. They reported mixed success so far, which is particularly impacted by the dry weather:

    - The organic farm in Shropshire drilled clover (2kg/ha) at the same time as buckwheat (50kg/ha) with the intention of following this on with winter oats. He will use sheep to graze the mulch in the winter.

    - The zero-till farmer in Staffordshire said that both weeds and crops are suffering from the dry weather and that any clover they can find has not been intentionally sowed.

    - The conventional and organic farmer in Oxfordshire reported that some clover is showing through

    - The organic grower in Worcestershire has not yet drilled the clover

    - The grower in Cambridgeshire has seen little establishment so far

    Milestone: Soil and cash/cover crop tissue analysis

    April 2020

    Mulches undersown

    The group have undersown the living mulches into winter and spring wheat. Warm weather from mid-March meant that some farmers decided to undersow the mulches as early as possible, to avoid too much cover from the winter wheat. Others sowed in mid-late April, hoping for a period of rain.

    The dry weather has caused some concern; the lack of rain has meant that the mulches haven't yet emerged at any of the farms. "Moisture for a few days after sowing and an occasional drop through the summer seems to be the crucial thing", one farmer commented.

    Milestone: Clover cover crops drilled

    March 2020

    Areas of debate

    Areas of debate amongst farmers in the trial:

    - Clover varieties. The group chose Aberace (small leaf clover) and Aberpearl (small to medium clover). Taller varieties would interfere with harvesting
    - Drill - strip vs disc
    - 100% clover ground cover vs clover strips
    - Managing clover to control growth and release fertility - livestock vs interrow mower/crimper; chemical and fertiliser for conventional growers.
    - Crop choices, timing of treatments, drilling dates
    - Impact on rotations

    Milestone: Proposal submitted

    March 2020

    Background to the triallists

    Of the triallists, some are already practicing long term conventional no-till and are looking to reduce chemical inputs, while others are established organic farmers looking to reduce tillage – both farming systems can learn from each other. More info on some of the triallists:

    Jamie Stephens is an organic farmer in Worcestershire and grass leys play a key role in building soil fertility and grazing for his flock of 800 sheep. 50% of the 340ha area is down to grass at any one point.

    James Alexander manages an organic arable farm in Oxfordshire and contract farms three other conventional farms. His hope is that the living mulches might enable fertility building without needing to take land out of production every year for clover leys. Generally, the conventional rotation involves 2-year pasture, winter wheat, spring barley, and oilseed rape. The organic rotation is a 2-year pasture, spring beans, spring/winter wheat, spring barley and oats. A flock of sheep graze at the organic site.

    Clive Bailye is a zero-till farmer in Staffordshire. Without livestock in the system, he is looking to living mulches as a potential way to build soil fertility and facilitate a circular farm approach without livestock or the need for cultivation to control weeds.

    Mark Lea is an organic farmer in Shropshire, where livestock (beef cattle and Romney sheep) are very much part of the system. He also has a green waste compost system originally to replace artificial P&K. The biggest crop is oats, which grows very successfully as an organic crop, as well as specialist milling crops like spelt and rye. He grows spring peas for a legume break. He has undersown living mulches for 20 years since going organic and tends to broadcast the seed into spring cereals in May. He wants to reduce reliance on ploughing and at the same time reduce weed coverage.

    Milestone: Group meeting

    February 2020

    First group meeting

    The group had their first in-person meeting to discuss their experiences of using living mulches, practicalities of the trial and motivations for being involved. Full minutes including a summary of the literature on mulch management can be found in the 'Living Mulch Trial Minutes' document on this page.

    Key outcomes of the meeting:

    - Seven farms (including one educational/experimental site) will undertake the trial.
    - The living mulch will consist of a mix of wild white and small-medium leaved clovers in a 70:30 ratio, undersown into a cereal cash crop in spring 2020.
    - Mulch will be knocked back through grazing or topping with a cash crop direct or strip drilled in the Autumn.
    - This approach will be compared to a farm control consisting of current standard farm practice to enable a proper comparison of the two systems.
    - Two of the trials will take place on conventional no-till farms and 5 trials will take place on organic farms.

    Weed control (particularly for organic farmers) and cash crop yield are the main parameters farmers are interested in measuring.

    The researcher explained that the ecosystem service of weed suppression provided by the mulch will need to be balanced with its competitiveness, to ensure that cash crop competitiveness is maximised and mulch competitiveness is minimised. The key point is plant above-ground biomass rather than date of plant emergence: the plant that achieves the greater biomass early on remains the better competitor throughout the growth.

    A barrier discussed was the lack of machinery suitable for mowing the mulch. Clover and other forage legume crops fix N but only release N when their biomass is returned to soil, therefore cutting is necessary but made difficult due to lack of appropriate machinery.

    The group will communicate via WhatsApp, exact data to be collected will be decided between the group and researcher.

    Milestone: Group meeting

    August 2019

    Field lab proposal - background

    The act of tilling the soil has many functions in agriculture, including breaking up soil compaction, eliminating weeds, and incorporating cover crops for increased soil fertility. These functions are even more important for organic farmers who don’t have access to herbicides or mineral nitrogen fertilisers.

    Unfortunately tillage also releases carbon into the atmosphere, increases the risk of erosion, removes structure and destroys important fungal networks. Tillage is also fuel- and labour-intensive. Some farmers, both conventional and organic, practice reduced tillage or try to eliminate it altogether, through No-till.

    No-till agriculture, a technique which aims to grow crops with minimal soil disturbance, increases the amount of water that infiltrates into the soil, the soil's retention of organic matter, its cycling of nutrients and enhance its microbial community, particularly fungi.

    However, it is a system based on glyphosate and is still dependent on fertiliser and pesticide inputs. This has always presented a challenge to organic farmers wishing to employ this system, and may present a challenge to conventional, no-till farmers in the future if pesticide regulations change and glyphosate becomes unavailable.

    To achieve organic no-till farming, there needs to be an alternative to a system reliant on glyphosate to terminate cover crops and kill weeds, that can also supply adequate nutrition to feed the growing cash crop.

    The practice of living mulch systems, a kind of mixed cropping where one crop (main cash crop) produces the yield and the other covers the soil (clover cover crop), is an environmentally sound way to farm the land. Compared with standard cropping systems that feature ploughing and monocultures, living mulch systems have several agronomic advantages, such as efficient erosion control, weed suppression, improved soil structure, and self-regulation of pests and diseases.

    Milestone: Proposal submitted

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