UK Biochar Research Centre
Charchive Standard Biochars
Soils page photo
Key Staff Member:
Dr. Saran P. Sohi

The purpose is to deliver sound mechanistic understanding of biochar function in soil, and gain from this the predictive capacity required to 'prescribe' biochar in ways that are firstly safe, and secondly offer the best possible results in terms of soil and crop performance and ecosystem services at new locations.

The resolution and certainty of the understanding that we seek is driven by the need to assign a financial value to biochar products based on (a) benefit to the agricultural enterprise, and (b) achievement of ecosystem services such as carbon storage, management of diffuse pollution, and mitigation of trace gas emission from agriculture.

This needs general relationships to be established linking biochar function with the biochar product as defined by feedstock and manufacturing process. The practical tools (rapid assays) that allow sets of biochar products to be assessed according to their functional properties in soil were the focus of our activity during our first year.  These tools can also underpin deployment activities elsewhere, providing site-specific optimisation of performance.

To establish these relationships using systematically produced sets of biochar samples balance impacts on soil function with net carbon-equivalent gain at the system level, this work is inextricably linked to studies of the production of biochar from biomass and the integrated assessment of the pyrolysis–biochar system.

An important consideration in terms of soil function is the dynamic as well as magnitude of biochar characteristics, since it should be possible to manipulate the timescale over which benefits from biochar in soil are delivered. The plant is both the potential beneficiary for impacts on soil function, but can also interact through the roots to modify function. Biochar may also modify the behaviour of plant roots.

For these reasons, the interaction between plant roots and biochar is being assessed at various levels, from simple microcosms to triangulation with small-scale field studies. In collaboration with Rothamsted Research we are involved in an isotope-tracer experiment that seeks to establish how the stabilisation of root-derived carbon (organic matter from root exudation) is affected by the presence of biochar (click here).

In summary, we are in the initial stages of a strategic programme of research where a set of novel screening tools will soon provide for a systematic evaluation of products from alternative pyrolysis technologies, across a sliding-scale of the key process variables that dictate the nature and properties of biochar, and a general understanding of how different plants interact with biochar (cereal crops, perennial grasses, bioenergy crops).

The predictive capacity from these activities will guide the selection of products for use in field experiments. Over the next few years an increasing number of field-based activities will assess our predictive capacity for a purposeful selection of biochar products, and refinement and validation of this emerging, laboratory-derived understanding of biochar function.

Relevant Research Areas: