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Managing a living mulch with maize for soil protection and crop health

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In this field lab Andy Gray, a farmer in mid Devon, is keen to trial different techniques of managing a clover living mulch under his maize crop

Growing maize is often associated with soil erosion and runoff.  This is partly because it is usually established using heavy cultivation, and harvested late in the year when the weather is often wetter.  It is best practice to establish an overwinter cover crop to protect the bare soil after harvest, but this does not protect the soil for the rest of the year.  There is often a long period when the soil is bare, especially whilst the maize is establishing, and immediately after harvest while the cover crop is germinating, leaving it open to erosion.

The benefits

A perennial, clover-based cover crop, or living mulch, should:

  • provide year-round ground cover in the maize fields, protecting the soil from erosion and nearby watercourses from nutrient rich runoff.
  • provide nitrogen to the crop, (through N fixing) thereby reducing the need for synthetic fertilisers.
  • Reduce the annual weed burden within the maize crop
  • Provide grazing immediately after the maize harvest without the need to wait for the cover crop to establish
  • Increase soil organic matter and soil carbon storage 

However, maize is a very uncompetitive crop, and it is generally thought that a living mulch would reduce maize growth and therefore yield.

By trialling different methods of managing the living mulch, Andy hopes to suppress the living mulch long enough for the maize to establish, but still maintain the year-round ground cover.

Trial design

The trial will last 3 years.

Year 1: Andy will undersow his maize crop with a clover cover crop at the 3-leaf stage of maize growth.  Any gaps in the cover can be reseeded after maize harvest. Baseline soil carbon levels have been captured as part of a separate project

Year 2: Before maize drilling the plots will receive different treatments:

1 – heavy grazing with sheep to reduce the clover to ground level

2- herbicide treatment to knock the clover back but not kill it

3- control (no management)

The maize yield will be measured using a weigh bridge at hearvest

Years 3 & 4: repeat

At the end of the trial samples will be taken of soil organic matter and soil carbon.

Latest updates

The trial fields are looking good.  Andy applied glyphosate to the clover in his  herbicide trial plot earlier in the year, though it does not appear to have knocked back the living mulch at all!


The maize can be seen in the bare soil rows between the living mulch.  The big question now is whether or not the the clover will be too vigorous for the maize.  The leaves are not quite as 'micro' as we'd hoped. However, the maize tap root has already gone below the clover, so it may get away before the clover encroaches / competes too much...


Maize tap root now deeper than the clover roots


The maize has now been harvested leaving the clover living mulch in the field.  The living mulch is quite patchy and parts need to be reseeded.

Once the maize reached the 3-leaf stage it was undersown with the clover cover crop / living mulch.

After a difficult few weeks in terms of weather, the maize has been drilled in the trial field 

Maize drilled

May 2023

Maize undersown with living mulch

June 2023

Maize yield analysis

Sep 2023

Maize harvest

September 2023

Treatments - grazing and herbicide application

April 2024

Maize strip tilled into 'treated / managed' living mulch

May 2024

Repeat year 1

Years 2 and 3

Soil sampling following year 4 harvest

Sep / Oct 2026

Group Coordinator

A portrait of Laura Gude.
Laura Gude

Soil Association

Bristol / South West

As the Innovative Farmers Network Coordinator, Laura engages with farmers, scientists, industry bodies and advisors to launch on-farm trials, ensure they keep running smoothly, and to share results. With an MSc in Sustainable Rural Development, Laura trained as a land agent. She then worked as a farming advisor in Devon, particularly on projects aimed at reducing diffuse water pollution in river catchments.


A portrait of Andy Gray.
Andy Gray

Elston Farm



A portrait of Kevin Godfrey.
Kevin Godfrey


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