UK Biochar Research Centre
Charchive Standard Biochars

Dr. Saran P. Sohi

photo of Dr. Saran P. Sohi
Leader: Soil Science, UKBRC
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Research Gate page here and Google Scholar here. Join me on LinkedIn.

Read my biochar "Perspective" in Science (23rd Nov 2012) via my publications page, on the University website (full text).

I was recruited to lead soil science research in the UK Biochar Research Centre, Edinburgh, at its inception in late 2008. I moved to Edinburgh in February 2009, and our Centre launched on April 1st.

The purpose of my work is to deliver UKBRC a sound mechanistic understanding of biochar function in soil, and gain from this the predictive capacity required to 'prescribe' biochar in ways that firstly are safe, and secondly offer the best possible results in terms of soil and crop performance at previously untested locations. The resolution and certainty of the understanding that we seek is driven by the need to assign financial value to biochar products reflecting (a) benefit to the agricultural enterprise, and (b) achievement of societal goals such as carbon storage, management of diffuse pollution, and mitigation of trace gas emission from agriculture. My work is inextricably linked to those of my colleagues who lead research into the optimising pyrolysis processes for the conversion of biomass into biochar, estimation of carbon-equivalent gains offered by pyrolysis-biochar systems, and scoping associated socio-economic issues including land-use.

The practical tools that we have established and published provide  rapid assays for the screening of biochar according to five key functional properties in soil. As well as being able to establish the full (wide) range of properties exhibited by bicohar (publication forthcoming), they provide for the optimisation of the use and performance of biochar in contrasting locations and circumstances, addressing specific constraints to crop production. The dynamics of biochar properties have been investigated in this process too - and it may be possible to manipulate the timeframe over which benefits from biochar are delivered in the soil. Simultaneously, we seek to exploit the findings from our published mesocosm work, to develop products that exploit interactions found to occur between biochar and plant roots.  

In undertaking directed, purposeful testing of biochar and biochar products in a range of environments (Ghana, China, Brazil, etc.), we also triangulate between laboratory work and controlled field experiments, notably the longest running UK field experiment with biochar, established in conjunction with Rothamsted Research in 2009. There we instigated an isotope-tracer experiment can hlep establish how the stabilisation of root-derived carbon (organic compounds from root exudation) are affected by the presence of biochar.

We are thus well advanced in a strategic programme of research, where a set of novel screening tools support a systematic evaluation of how alternate biomass conversion technologies and a sliding-scale for pyrolysis variables, which dictate the nature of biochar products. The knowledge that is gained here, combined with an understanding of how different plants interact with biochar (cereal crops, perennial grasses, bioenergy crops) are guiding the products that we are using in trials.

Soil Science research in UKBRC Edinburgh currently involves one post-doctoral researcher, one research scientist and a number of PhD students (some in conjunction with SRUC. formerly SAC). We link to a network of international collaboraors and guide a number of student research projects at MSc and BSc level.

My own research background is in the elucidation of soil organic matter dynamics from modelling measured dynamics of key physical fractions, the topic of my PhD and eight years post-doctoral work at Rothamsted Research, the BBSRC research institute based in Harpenden, Hertfordshire. Biochar should not be considered a distinct soil science discipline, and I seek to ensure that knowledge and experience gained from study and simulation of other recalcitrant organic matter fractions - and their interaction with more labile components - is not ignored in seeking understanding of biochar function. By way of example, existing understanding of the contrasting dynamics and interaction of soil fractions was used, in combination with simulation and isotope tracers, to assess the effect of charcoal in terra preta soils on the turnover of other soil carbon. This was my introduction to biochar soil science, and a consequence of collaborative research instigated at Cornell University, NY, where I worked in the group of Johannes Lehmann during 2005.

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