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Long term Biochar versus Wood Ash Agronomic Field Trial

Title of Experiment: Long term Biochar versus Wood Ash Agronomic Field Trial

Date started: August 2014

Contact: Prof Davey Jones (

Funding source: European Union SEREN programme

Location: Henfaes Experimental Lowland Station

Experimental Aims:

  1. To directly compare the agronomic value (e.g. fertiliser replacement value, productivity) of biochar versus wood ash when used in grassland management.
  2. To evaluate the impact of biochar and wood ash on soil quality at the field scale over multiple seasons
  3. To assess the impact of biochar and wood ash on ecosystem service delivery
  4. To compare the benefits of biochar and wood ash using a life cycle approach
  5. To evaluate farmer opinion on the use of biochar and wood ash in grassland management

Brief description

The trial is located at the Bangor University Henfaes Experimental Farm in the lowland part of the farm. The trial was set up to evaluate whether the product of wood pyrolysis (i.e. biochar) was better than the product of incineration (i.e. wood ash) when used in grassland management (for sheep grazing and silage production).

The trial was located next to the existing long-term biochar trial; however, the nature of the biochar used in this trial was different to that used previously. Although the origin of the biochar was the same (mixed hardwood created under the same pyrolysis conditions), in the new trial the biochar was pulverised to a fine powder to maximise its surface area (the old trial used large biochar chips). The wood ash was created from the biochar so that they were directly comparable. Mixed hardwood biochar was added in a randomised block design field trial at two rates in 2014 (0 or 10 t ha-1). Wood ash was added at a rate equivalent to 10 t ha-1 of biochar which equated to about 0.57 t ha-1 (i.e. ash content of biochar ca. 5.7%). There are 4 replicates of each treatment.

A map of the field trial is given below. In year 1 (2014), we prepared the ground in August and applied the treatments in September. The material was then power harrowed in and seeded with perennial ryegrass. The soil at the site is a fertile Eutric Cambisol. There is a Met station located on site. We are studying various aspects of soil and plant quality within this trial including forage growth and yield, soil biodiversity, greenhouse gas emissions, soil nutrient effects, nitrogen and carbon dynamics, water dynamics etc. The staff involved in the work include Dr Eleanor Swain supported by Prof Davey Jones, Prof Dave Chadwick, Prof John Healey and Dr Prysor Williams.

The image below shows the Licor multichannel respirometer measuring greenhouse gas emissions from the plots.


We welcome collaboration on this trial. We can host visits and supply samples for research purposes to interested parties from the UK and overseas. The contact details are listed at the top of the page.

Publications arising from this experiment

None as yet