WurCel: Root-derived soil organic carbon accumulation

Background and Objective

Studies have shown that root biomass contributes more to soil organic carbon accumulation in soils than above-ground biomass. Consequently, selecting species and varieties of primary and cover crops with high root biomass might be an effective measure to help mitigate climate change. However, little data is available on the root biomass of modern crops. The "WurCel"-project aims at contributing to close this knowledge gap by sampling roots of primary and cover crops across Germany. Based on this data we will estimate the potential to improve carbon accumulation in agricultural soils by selecting species and varieties with high root biomass.

Approach

We will sample and characterize roots of primary and cover crops from field trials across Germany. Additionally, we will use experiments to study the effects of a 20% reduction in nitrogen fertilization (as contained in the EU "farm to fork" strategy) and of an increased atmospheric CO₂ concentration on root biomass of important crops. We will also investigate the effect of deep-rooted plants on soil carbon of deep soil layers using a stable isotope approach. The collected data will be used in combination with process-based soil carbon models to estimate how much additional carbon could be stored in German agricultural soils by selecting species and varieties of crops and cover cops with high root biomass.