Making the Most of Green Manures

A Webinar for Farmers

Resource explained

Green manures and cover crops can be grown to benefit the following crop primarily by improving soil quality. Ian Wilkinson of Cotswold Seeds presents this 54 minute long webinar providing a guide to green manures and cover crops for farmers. He describes how to use them, how they work and some of the benefits; focusing on nitrogen management, species mixtures, and how you sow and grow them. Ian proposes that green manures can be a very valuable part of arable rotations by improving soil quality. They can also allow for an extra income stream through grazing livestock, and benefit the environment by providing pollen and nectar, reducing erosion, encouraging water infiltration, and reducing the need for artificial fertilisers. The webinar includes a mixture of clear illustrations and photographs to explain how you can effectively use green manures.

Findings & recommendations

  • It is recommended that a mixture of species with different properties are grown, this allows for multiple benefits and can increase yields by up to 47%.
  • Green manures are mainly grown to provide organic matter for soil organisms. These organisms break down plant material to provide nutrients for following crops.
  • Leguminous species (e.g. clovers, vetches) fix nitrogen from the atmosphere into the soil for free, adding between 80-300 kg of nitrogen per hectare.
  • Green manures can suppress weed plants by outcompeting them.
  • They should be sown between spring and autumn; either directly or undersown into the current crop.
  • They can be short term (6-10 weeks) or long term (2-3 years).
  • They should be destroyed before the following crop is planted.
  • Chemical destruction involves weed killer, but this can have a detrimental effect on soil biology so is best avoided.
  • Mechanical destruction includes mowing the crop, ploughing it in, or using a crimper roller to crush the plants.
  • Biological destruction involves grazing livestock on the green manure. This is very efficient and provides extra farm income as well as further improving fertility with animal manure.
  • Ian cites examples of practices various farmers are using to help illustrate points in the webinar.

Also see ‘Sort out your soil‘

 

Associated Agricology Partner Organisation(s):

VIEW RESOURCE

Author(s):

Wilkinson, I

Funders:

Prince of Wales’s Charitable Foundation

Organisation(s):

  • Innovative Farmers

Date:

01/03/2016

Evidence:

Applied research

Copyright:

Public Domain

Related theme:

Key Farming Practices:

Related articles

Good Green Manures

A field lab report comparing four green manure mixes; investigating their effect on soil structure and quality, benefits to the following crop, and their value.

Manifold green manures – Part 4: Large birdsfoot trefoil, meadow pea and white clover

An article outlining properties of three species that could be considered for fertility-building mixes, trialled in the Legume LINK project.

Manifold green manures – Part I: Sainfoin and birdsfoot trefoil

An article outlining properties of two species that could be considered for fertility-building mixes, trialled in the Legume LINK project.

Manifold green manures Part 2: Alsike and crimson clovers

Details on alsike and crimson clover that will help assess suitability for inclusion in fertility-building mixes, as defined in Legume LINK.

Manifold green manures Part 3: Black medic and lucerne

Two lesser-used legume species with properties that you can make use of in fodder, green manure or hay crops, as highlighted in Legume LINK.

Short-term green manures for intensively cultivated horticultural soils

A GREATsoils factsheet detailing the main green manure species suitable for use in high value vegetable and salad rotations and summarising benefits they can bring

Sustaining our soils: Getting the balance right

Recording of an Organic Growers Alliance's Organic Matters 22 conference session exploring stockfree organic standards and carbon sequestration, mobile green manures, Organic-PLUS trials on fertility-building...

Sort out your soil

This Cotswold Seeds / Garden Organic publication provides detailed, practical information to help you select and use green manure crops.

Cover Crops

Guidance on selecting and managing cover crops according to your requirements, outlining financial, agronomic and environmental benefits.

Opportunities for cover crops in conventional arable rotations

An introduction to the potential environmental and agronomic benefits of cover crops in arable systems.

Establishing summer cover crops before winter cereals in low tillage systems on sandy soils

Abstract created as part of the DiverIMPACTS project outlining some of the benefits that can be attained from establishing summer cover crops on sandy soils...

Ian Wilkinson

Cotswold Seeds purchased the farm in 2013 with aim of developing it as a centre for farming diversity, demonstrating how small family farms can use...
To top