Locked Up

Locked Up: The role of biotic and abiotic interactions in the stabilisation and  persistence of soil organic carbon

Loss of soil organic carbon through human land use is one of the most pressing environmental challenges of the 21^st century. Soil carbon loss contributes to climate change, makes soils less suitable for crops, reduces soil fertility through associated loss of nitrogen and phosphorous as plant nutrients, and reduces water holding capacity and drainage to aquifers - adversely impacting drought and flood resistance, water quality and water availability.  It is estimated that the world’s soils hold 4-8 times the amount of carbon in terrestrial vegetation, yet the loss of carbon from this important reservoir is an escalating global threat caused by unsustainable land management practices.

Maintaining and increasing soil carbon stocks globally is critical to ensuring food security and mitigating climate change. Small increases in soil carbon over very large areas could significantly reduce net carbon dioxide emissions from agriculture.

This project will help to achieve this by advancing our understanding of what makes carbon stable in soils and developing quantitative methods to assess the mitigation potential and feasibility of increasing soil carbon storage across UK and global soils.

Locked Up will transform our knowledge of the processes and mechanisms of soil organic carbon production and persistence in soil to inform land management innovation, and quantify the capacity and time scale to increase persistent - i.e. “LOCKED UP” - soil carbon stocks. The project aims are to:

• Deliver a step-change in fundamental understanding of the abiotic and biotic mechanisms of soil carbon stabilisation and persistence
• Identify the capacity of soils to increase stable SOC stocks and inform sustainable soil carbon land management strategies
• Contribute evidence on the feasibility of achieving “4 per thousand” increases in soil carbon sequestration across global soils, land uses and climate change scenarios

Team:

UKCEH Lancaster       Project lead Dr Jeanette Whitaker, Dr Niall McNamara, Dafydd Elias, Kelly Mason

UKCEH Bangor           Dr Rob Griffiths

UKCEH Wallingford    Dr Tim Goodall

University of Leeds    Prof Caroline Peacock, Prof Joseph Holden, Dr Pippa Chapman,
                                     Prof Steve Banwart, Dr Alba Otero-Fariña, Prof Katie Field, Dr Tom Thirkell

Lancaster University  Prof. Nick Ostle, Dr. Hongmei Chen

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We propose that persistent soil carbon is produced by a series of complex but testable interactions between soil microbes and soil minerals.  We will test this through four work packages (WP) using a combination of novel and state-of-the-art experimental, analytical and modelling approaches:

WP1: Biotic and abiotic controls on carbon stabilisation in model systems: To determine how the quantity, nature and rates of stabilised organic carbon are regulated by microbial community structure, the edaphic environment and stress physiology.

WP2: Minerals and organic carbon preservation: To determine how the chemical identity of organic carbon and minerals influences the formation, stability and degradation potential of organo-mineral complexes and aggregates. 

WP3: The influence of plant inputs to soil (exudates and litter) on carbon stabilisation and destabilisation: To quantify how the chemical and physical nature of plant inputs to soil determines the net balance of stabilisation and destabilisation.

WP4: The resilience of soil carbon to future climate and land-use change: To test the resilience of SOC persistence in soils with distinct mineralogies, vegetation and land use. 

WP5: Soil process modelling: To quantify the capacity and time scales of SOC persistence which can be achieved through land management