Report on Energy-Model, microbial CUE and C-sequestration: Deliverable 6.1 Towards climate-smart sustainable management of agricultural soils

Crop diversification is a potentially attractive agricultural practice for enhancing organic carbon (C) storage in soils. The aim of EnergyLink is to better understand the link between crop diversity and carbon sequestration by the soil microbiome across a pan-European pedo-climatic gradient. The central hypothesis is that greater crop diversity results in more efficient microbial use of C, thus enhancing the potential of soils to store C. The underlying mechanisms will be elucidated by combining classical and molecular level methods in a bioenergetics framework.
Work package 6 on “Soil Organic Matter Modelling” aims to assess the relative impact of including the soil microbiome in models for soil organic C (SOC) sequestration on the assessment of C sequestration. More specifically, task 6.1 aims to express the relationship between the microbial biomass pool and SOC dynamics. For this purpose, a hypothetical model has been formulated. Potential indicators have been screened for their suitability to be included in SOC-models, i.e. microbial carbon use efficiency (CUE) and the energetic return on metabolic investment (ROI). The indicator offering the highest perspective for inclusion in SOC models is the carbon use efficiency (CUE). Subsequently, this indicator is recommended for the planned work on adapting a SOC-model. With this adapted model, the relative impact of the soil microbiome on the formation and persistence of SOC under different pedo-climatic conditions will be assessed.