Assessing soil carbon dioxide and methane fluxes from a Scots pine raised bog-edge-woodland

Acknowledgements: We thank the James Hutton Institute Aberdeen for providing laboratory and transport facilities, especially Richard Hewison, who completed the vegetation survey of the site and Graham Gaskin and Alison Wilkinson for providing assistance with field equipment. Author J Yeluripati was supported by the Scottish Government’s Strategic Research Programme (2016–2021): Research Deliverable 1.1.3: Soils and Greenhouse Gas Emissions. I also thank William Jessop (York University), who provided peat depth measurements and my dearest friends Anna Ferretto, Luka Paradiz Udovc, Douglas Wardell-Johnson, Ben Butler, Lucho Quinzo and Ben M. Taylor for offering their invaluable help with field measurements. We lastly thank Toni Clarcke for helping with statistical analysis and Michael Bell (Forest Research) for improvements to the manuscript. Funding: This research was funded by Scottish Forestry and the University of Aberdeen.Peer reviewedPostprin

What makes an operational Farm Soil Carbon Code? Insights from a global comparison of existing soil carbon codes using a structured analytical framework

Soils have the potential to sequester and store significant amounts of carbon, contributing towards climate change mitigation. Soil carbon markets are now emerging to pay farmers for changes in land use or management that absorb carbon from the atmosphere, governed by codes that ensure additionality, permanence and non-leakage whilst protecting against unintentional reversals. This paper represents the first global comparative analysis of agricultural soil carbon codes, providing new insights into the wide range of approaches currently used to govern these emerging markets internationally. To do this, the paper first develops an analytical framework for the systematic comparison of codes, which could be applied to the analysis of codes in other land uses and habitats. This framework was then used to identify commonalities and differences in methods, projects, administration and commercialisation and associated code documents for 12 publicly available codes from the UK, France, Australia, USA and international bodies. Codes used a range of mechanisms to manage: additionality (including legal, adoption, financial viability and investment tests); uncertainty and risks around soil carbon sequestration (including minimum permanence periods, carbon buffers, contractual arrangements and/or insurance policies); leakage (including restriction of eligible practices and monitoring to subtract leakage from verified sequestration); baselines (including multi-year and variable buffers based on empirical data or models); measurement, reporting and verification methods (stipulating time intervals, methods, data sources and assessments of uncertainty); auditing; resale of carbon units; stakeholder engagement; and approaches to ensure market integrity (such as buyer checks). The paper concludes by discussing existing MRV methods and codes that could be adapted for use in the UK and evaluates the need for an over-arching standard for soil carbon codes in the UK, to which existing codes and other schemes already generating soil carbon credits could be assessed and benchmarked

Simulation of Soil Organic Carbon Effects on Long-Term Winter Wheat (Triticum aestivum) Production Under Varying Fertilizer Inputs

Acknowledgments We appreciate the financial support from EC SMARTSOIL project (Project number: 289694) for funding the collation of long-term experimental data from the project partners and Mr. Per Abrahamsen for helping with the DAISY model. The support from LANDMARK (Grant Agreement No: 635201), WaterFARMING (Grant Agreement No: 689271), and SustainFARM (Grant Agreement No: 652615) projects are acknowledged to carry out revisions and improvement of the scientific content for resubmission of the manuscriptPeer reviewedPublisher PD

First 20 years of DNDC: Model evolution and GRAMP.

The DNDC (DeNitrification and DeComposition) model was first developed by Li et al. (1992) as a rain event-driven process-orientated simulation model for nitrous oxide, carbon dioxide and nitrogen gas emissions from the agricultural soils in the U.S. Over the last 20 years, the model has been modified and adapted by various research groups around the world to suit specific purposes and circumstances. The Global Research Alliance Modelling Platform (GRAMP) is a UK-led initiative for the establishment of a purposeful and credible web-based platform initially aimed at users of the DNDC model. With the aim of improving the predictions of soil C and N cycling in the context of climate change the objectives of GRAMP are to: 1) to document the existing versions of the DNDC model; 2) to create a family tree of the individual DNDC versions; 3) to provide information on model use and development; and 4) to identify strengths, weaknesses and potential improvements for the model

Mapping paddy rice agriculture in South and Southeast Asia using multi-temporal MODIS images

In this paper, we developed a new geospatial database of paddy rice agriculture for 13 countries in South and Southeast Asia. These countries have ∼ 30% of the world population and ∼ 2/3 of the total rice land area in the world. We used 8-day composite images (500-m spatial resolution) in 2002 from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor onboard the NASA EOS Terra satellite. Paddy rice fields are characterized by an initial period of flooding and transplanting, during which period a mixture of surface water and rice seedlings exists. We applied a paddy rice mapping algorithm that uses a time series of MODIS-derived vegetation indices to identify the initial period of flooding and transplanting in paddy rice fields, based on the increased surface moisture. The resultant MODIS-derived paddy rice map was compared to national agricultural statistical data at national and subnational levels. Area estimates of paddy rice were highly correlated at the national level and positively correlated at the subnational levels, although the agreement at the national level was much stronger. Discrepancies in rice area between the MODIS-derived and statistical datasets in some countries can be largely attributed to: (1) the statistical dataset is a sown area estimate (includes multiple cropping practices); (2) failure of the 500-m resolution MODIS-based algorithm in identifying small patches of paddy rice fields, primarily in areas where topography restricts field sizes; and (3) contamination by cloud. While further testing is needed, these results demonstrate the potential of the MODIS-based algorithm to generate updated datasets of paddy rice agriculture on a timely basis. The resultant geospatial database on the area and spatial distribution of paddy rice is useful for irrigation, food security, and trace gas emission estimates in those countries

Measurements necessary for assessing the net ecosystem carbon budget of croplands

There are a number of methods that can be used to help assess carbon budgets at the site to continental scales. Eddy covariance (EC) networks have been developed over the last decade and have been used to make many advances in our understanding. However, eddy covariance measurements of CO2 and water vapour exchanges quantify the fluxes only on short time scales, but do not assess the impacts of long-term processes that contribute to biogeochemical cycling in croplands, such as harvest or residue removal and other management practices, so many other supplementary measurements are required to attribute different components of the carbon flux. Such methods include isotope studies, chamber flux measurements of C and other greenhouse gases, inventories of above- and below-ground biomass as well as management in- and outputs, book-keeping modelling, process modelling, experimental manipulation and earth observation (e.g. remote sensing). In this review, we summarise the component fluxes that make up the total cropland carbon budget, describe the key fluxes and methods used to estimate them, and examine how they need to be integrated to obtain the net ecosystem carbon budget of European croplands. We describe the uncertainties and difficulties inherent at each stage and how these can be minimised

Systems approaches in global change and biogeochemistry research

Systems approaches have great potential for application in predictive ecology. In this paper, we present a range of examples, where systems approaches are being developed and applied at a range of scales in the field of global change and biogeochemical cycling. Systems approaches range from Bayesian calibration techniques at plot scale, through data assimilation methods at regional to continental scales, to multi-disciplinary numerical model applications at country to global scales. We provide examples from a range of studies and show how these approaches are being used to address current topics in global change and biogeochemical research, such as the interaction between carbon and nitrogen cycles, terrestrial carbon feedbacks to climate change and the attribution of observed global changes to various drivers of change. We examine how transferable the methods and techniques might be to other areas of ecosystem science and ecolog