Evaluating carbon sequestration mechanisms in soil applied with novel fertiliser

Overview

This research investigates the carbon dynamics of a novel pelleted fertiliser produced by capturing point-source CO2 into organic waste streams. The work addresses a critical question for climate-smart agriculture: whether carbon introduced via the fertiliser stabilises or accelerates the breakdown of carbon already present in the organic waste and in receiving soils. By clarifying these interactions, the research aims to support fertiliser formulations that sequester carbon effectively while releasing minimal nitrous oxide, methane, and CO2.

The value proposition is twofold. For fertiliser producers and agri-businesses, it offers an evidence base for designing low-emission, carbon-negative soil amendments derived from waste and captured industrial emissions. For policymakers and sustainability-focused organisations, it provides data on whether such products contribute genuine soil carbon storage or simply shift emissions from one source to another.

Technical specifications

The research uses mesocosm experiments (5 cm diameter by 10 cm height) to test three formulations of the novel fertiliser against a control, with five replications per treatment.

Key features:

• Mesocosms maintained at 40% water holding capacity to standardise moisture conditions
• Continuous greenhouse gas flux measurement (nitrous oxide, methane, CO2) over a four-month period using a Picarro analyser connected to individual chambers
• Soil and fertiliser mixtures analysed for total and organic carbon, organic matter, pH, and total and extractable nitrogen, phosphorus, and potassium at the start and end of the experiment
• Statistical analysis performed using STATISTICA software
• Planned thermogravimetric analysis to assess carbon stability of adjusted fertiliser formulations
• Planned physisorption and chemisorption characterisation of pellets to quantify porosity, surface area, pore volume, and breakdown behaviour in soil

Technology readiness level

The work is at the experimental validation stage, with mesocosm trials already underway and initial gas flux and soil chemistry data being generated. Future validation will refine fertiliser carbon content to optimise sequestration across varying soil moisture conditions and will use thermogravimetric and sorption-based characterisation to link pellet properties to carbon storage and gaseous emissions outcomes. The fertiliser concept itself builds on an existing capture-to-organic-waste conversion process, positioning the research to inform formulation optimisation and eventual field-scale testing.