True SOC sequestration: understanding trade-offs and dynamic interactions between SOC stocks and GHG emissions for climate-smart agrisoil management.

Carbon sequestration in soils is an effective way to remove carbon dioxide (CO₂) from the atmosphere and mitigate climate change. In addition, increased soil organic matter is associated with multiple benefits for ecosystem functioning including crop productivity and food securing, water retention and flood/erosion control, nutrient cycling and pollution and soil biodiversity.

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Foreword

Agricultural soils are globally depleted in soil organic carbon (OC) and therefore, they exhibit a high potential for carbon sequestration under appropriate management practices. Several agroecological management practices aim to increase or retain soil OC through increased carbon inputs (e.g. organic amendments and plant litter), alternative cropping systems (e.g. continuous cover crop) and/or measures to reduce soil OC losses (e.g. reduced or no tillage and adaptive grazing). However, the same practices might increase greenhouse gas (GHG) emissions such as CO₂, nitrous oxide (N₂O) and methane (CH₄), restricting their effectiveness to mitigate climate change. To date, we still lack an understanding on the mechanisms and drivers behind increased GHG emissions and their interactions with OC sequestration under different soil and climatic conditions, partly because little is known about how abiotic and biotic factors control the extent to which soils can store OC. Quantifying negative side-effects of increased soil OC sequestration on GHG emissions is necessary to develop appropriate management options that reduce GHGs while increasing soil OC stocks.

Eine Wissenschaftlerin und ein Wissenschaftler arbeiten hinter einer Glasfassade und mischen Chemikalien mit Großgeräten.

Main objectives

TRUESOIL’s main goal is to assess how agricultural management influences soil carbon sequestration and GHG emissions from agroecosystems with distinct vegetation, soil properties and climates. Under field conditions, we will elucidate the role of different abiotic and biotic factors in OC storage and the extent to which these factors impact on GHG emissions, in particular N₂O, given its high warming potential and large uncertainty in flux estimates. Many carbon-sequestering management interventions are known, or have the potential, to modify soil N cycling leading to enhanced N₂O emissions.