Zoom into Soil: Carbon Sequestration

In this webinar, Peter Smith, Professor of Soils & Global Change at the University of Aberdeen, and Dr. Jagadeesh Yeluripati, Senior Scientist at the James Hutton Institute, discuss carbon sequestration in soils.

Professor Pete Smith will be speaking on ‘global potentials for soil carbon sequestration, co-benefits, drawbacks and the need for good verification’. Pete Smith is Professor of Soils and Global Change at the Institute of Biological and Environmental Sciences at the University of Aberdeen and Science Director of the Scottish Climate Change Centre of Expertise (ClimateXChange). His interests include climate change mitigation, soils, agriculture, food systems, ecosystem services modelling and nature-based solutions. He is a Fellow of the Royal Society of Biology, a Fellow of the Institute of Soil Scientists, a Fellow of the Royal Society of Edinburgh, a Foreign Fellow of the Indian National Science Academy, a Fellow of the European Science Academy, and a Fellow of the Royal Society (London).

Dr. Jagadeesh Yeluripati will be speaking on ‘Near-real-time monitoring, reporting, and verification system for low-carbon agriculture: A step towards net-zero.’ Jagadeesh is a Senior Scientist at the James Hutton Institute and has a background in environmental science and engineering. He has been conducting interdisciplinary research on impact of climate change on different production systems especially agriculture systems in several countries. His current research interests focus on interactions between terrestrial ecosystems and the global atmosphere, with a focus on soils and their role in global carbon and nitrogen cycling, to understand how the ecology of ecosystems may be shifting in response to global climate change.

Questions unanswered from the session

1) In the TOC graph (smith 2005) the manure treated is behaving strangely, why is that so?

THIS SLIDE SHOWS MODELLING OF REAL PRACTICES FROM THE FIELD EXPERIMENT, WHICH HAD REGULAR MANURE APPLICATIONS FOR THE FIRST PERIOD OF TE EXPERIMENT, THEN NO MANURE FOR A SHORT TIME, THEN MANURE ONCE EVERY FEW YEARS DURING THE MID-1900S – WHICH IS WHAT LEADS TO THE SAWTOOTH PATTERN IN TOTAL SOIL ORGANIC CARBON DURING THE MID-1900S.

2) How long is short term measurements for CO2 sequested ? How do we measure CO2 sequestration in the short term?

TO DEMONSTRATE SOIL CARBON YOU NEED MEASREMENTS OF SOIL ORGANIC CARBON OVER AT LEAST 10 YEARS. SHORTER-TERM CO2 (AND INDEED CH4 AND N2O) MEASUREMENTS ARE GREAT FOR CALIBRATING PROCESS DESCRIPTIONS IN COMPUTER MODELS, THAT CAN BE USED TO SIMULATE SOIL CARBON SEQUESTRATION.

3) Do you think the data is good enough to assess management options to improve soil carbon?

DEPENDS ON THE DATA! IF DATA IS COLLECTED USING A STANDARD PROTOCOL AT SUFFICIENT DENSITY OVER A LONG ENOUGH PERIOD, IT CAN BE GOOD ENOUGH TO ASSESS AMNAGEMENT PRACTICES THAT IMPROVE SOIL CARBON.

4) Isn’t eddy covariance measurement of CO2 emission too short term to be useful? Affected by weather on a daily basis – not useful for long term trends. And remote sensing using drones only sees surface soil – no data on soil C changes below this.

We are utilizing eddy covariance measurements for calibration purposes and employing soil carbon models to forecast long-term trends. However, we are not using drones to estimate soil carbon. Instead, we are using drones to estimate crop biomass, which we can then input into our models. It is our recommendation to establish baseline soil carbon measurements prior to undertaking MRV.

5) How confident are you in the soil C analysis techniques currently available as the basis of monitoring?

C&N ANALYSERS ARE CERTAINLY GOOD ENOUGH – BUT GETTING IN-FIELD ANALYSERS THAT ARE ACCURATE AND CHEAP ENOUGH TO MEASURE SOIL C IS THE BIG CHALLENGE, BUT THERE ARE SOME PROMISING (THOUGH NOT QUITE THERE YET) IN-FIELD SPECTRAL TECHNIQUES, E.G. YARDSTICK: https://www.useyardstick.com/

6) What do you think about the potential of biochar, it is much more long-term carbon which is less reversible?

I THINK BIOCHAR HAS POTENTIAL – THE CARBON HAS A LONGER RESIDENCE TIME THAN UNCHARRED MATERIAL SO IT COULD HELP (AND BE LESS REVERSIBLE) – BUT WE HAVE TO MAKE SURE THE FEEDSTOCK TO PRODUCE THE BIOCHAR IS SUSTAINABLE AND DIESN’T COMPETE FOR LAND.

7) Will there be scope to include England and Wales into the Retina model in the future?

Yes, we are working on this at this moment.

8) What are the thoughts on the application of ground basalt to capture carbon?

BASALT AND OTHER SILICATE ROCKS SHOW PROMISE AND THERE IS ACTIVE RESEARCH TO EXAMINE THE FULL POTENTIAL ONGOING: https://www.sheffield.ac.uk/uk-enhanced-weathering

9) Any compelling researching indicating that top soil depth can be increased with good management practise. The equilibrium data is carbon concentration but if soil depth is changing could total Soil C be increasing?

NOT REALLY – SOIL DEPTH INCREASES ON AVERAGE BY 1-2CM PER 500 YEARS, SO NO EVIDENCE THAT NEW SOIL WILL BE ADDED ON TOP – ONLY PALCE THIS HAPPENS IS IN PEATLANDS (COLD, WET AND ACIDIC).

10) Are there any considerations given to the biodiversity benefits of different grassland management systems, or is it a pure focus on carbon?

BY WHOM? ECOLOGISTS CERTAINLY CONSIDER BIODIVERSITY IMPACTS OF DIFFERENT GRASSLAND MANAGEMENT SYSTEMS. THERE IS GOOD EVIDENCE IT HAS A LARGE EFFECT OF BIODIVERSITY – NOT SO MUCH EVIDENCE OF SOIL CARBON BENEFITS.