Improved estimation and mitigation of nitrous oxide emissions and soil carbon storage from crop residues (ResidueGas)

Crop residues provide large inputs of carbon (C) and nitrogen (N) to soils and contribute to the net GHG balance of soils in different ways. They are included as a key component in national emissions inventories for nitrous oxide (N2O) from agriculture. Residue are also a major contributor to sustaining or enhancing soil organic carbon (SOC) and N contents and thus soil fertility. Depending on the amount of C and N in crop residues and their contributions to N2O emissions or to the SOC balance residues might increase or decrease the GHG footprint of agroecosystems.

Studies have shown that N2O emissions from N in crop residues vary considerably depending on residue quality, residue management and soils. This is currently not reflected in emissions inventories or likely not sufficiently in simulation models. This makes current emission inventories uncertain and in many cases biased. Lack of knowledge and precise model estimation of N2O emissions and SOC storage from crop residues limits the design of improved crop management systems for net GHG emissions reductions.

ResidueGas will document an improved methodology to quantify N2O emissions from agricultural crop residues management, including standards for estimating the amount of N in residues and improved emission factors for crop residue that include effects of residue quality, management, soils and climate on emissions. ResidueGas will further identify and communicate best practice for crop residue management strategies with respect to their net greenhouse gas effect in terms of N2O emissions and SOC storage.

The transnational team in ResidueGas has the necessary breadth of high-level expertise to undertake the task, covering knowledge on relevant cropping systems, measurements of GHG emissions (N2O and SOC) at both field and lab scales, access to existing data on crop residues and emissions, expertise in biogeochemical modelling of GHG emissions and knowledge on GHG inventory reporting at farm and national scale.