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- Harden, Jennifer W., et al.
(författare)
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Networking our science to characterize the state, vulnerabilities, and management opportunities of soil organic matter
- 2018
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Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 24:2, s. e705-e718
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Tidskriftsartikel (refereegranskat)abstract
- Soil organic matter (SOM) supports the Earth's ability to sustain terrestrial ecosystems, provide food and fiber, and retains the largest pool of actively cycling carbon. Over 75% of the soil organic carbon (SOC) in the top meter of soil is directly affected by human land use. Large land areas have lost SOC as a result of land use practices, yet there are compensatory opportunities to enhance productivity and SOC storage in degraded lands through improved management practices. Large areas with and without intentional management are also being subjected to rapid changes in climate, making many SOC stocks vulnerable to losses by decomposition or disturbance. In order to quantify potential SOC losses or sequestration at field, regional, and global scales, measurements for detecting changes in SOC are needed. Such measurements and soil-management best practices should be based on well established and emerging scientific understanding of processes of C stabilization and destabilization over various timescales, soil types, and spatial scales. As newly engaged members of the International Soil Carbon Network, we have identified gaps in data, modeling, and communication that underscore the need for an open, shared network to frame and guide the study of SOM and SOC and their management for sustained production and climate regulation.
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- Hergoualc’h, Kristell, et al.
(författare)
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Improved accuracy and reduced uncertainty in greenhouse gas inventories by refining the IPCC emission factor for direct N2O emissions from nitrogen inputs to managed soils
- 2021
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Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 27:24, s. 6536-6550
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Tidskriftsartikel (refereegranskat)abstract
- Most national GHG inventories estimating direct N2O emissions from managed soils rely on a default Tier 1 emission factor (EF1) amounting to 1% of nitrogen inputs. Recent research has, however, demonstrated the potential for refining the EF1 considering variables that are readily available at national scales. Building on existing reviews, we produced a large dataset (n = 848) enriched in dry and low latitude tropical climate observations as compared to former global efforts and disaggregated the EF1 according to most meaningful controlling factors. Using spatially explicit N fertilizer and manure inputs, we also investigated the implications of using the EF1 developed as part of this research and adopted by the 2019 IPCC refinement report. Our results demonstrated that climate is a major driver of emission, with an EF1 three times higher in wet climates (0.014, 95% CI 0.011–0.017) than in dry climates (0.005, 95% CI 0.000–0.011). Likewise, the form of the fertilizer markedly modulated the EF1 in wet climates, where the EF1 for synthetic and mixed forms (0.016, 95% CI 0.013–0.019) was also almost three times larger than the EF1 for organic forms (0.006; 95% CI 0.001–0.011). Other factors such as land cover and soil texture, C content, and pH were also important regulators of the EF1. The uncertainty associated with the disaggregated EF1 was considerably reduced as compared to the range in the 2006 IPCC guidelines. Compared to estimates from the 2006 IPCC EF1, emissions based on the 2019 IPCC EF1 range from 15% to 46% lower in countries dominated by dry climates to 7%–37% higher in countries with wet climates and high synthetic N fertilizer consumption. The adoption of the 2019 IPCC EF1 will allow parties to improve the accuracy of emissions’ inventories and to better target areas for implementing mitigation strategies.
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- Milne, Eleanor, et al.
(författare)
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Methods for the quantification of emissions at the landscape level for developing countries in smallholder contexts
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The GHG (greenhouse gas) mitigation potential from the agricultural sector is set to increase in coming decades. Much of the agricultural mitigation potential lies in developing countries where systems are dominated by smallholder farmers. There is therefore an opportunity for smallholders not only to gain environmental benefits from carbon friendly practices, but also to receive much needed financial input, either directly from carbon financing, or from development agencies looking to support carbon friendly activities. However, the problem remains of how to quantify carbon gains from mitigation activities carried out by smallholder farmers. Landscape-scale quantification enables farmers to pool resources and expertise, which can put participation in carbon markets and access to other funding sources, within their reach. Therefore, funding agencies, governments and NGOs are increasingly recognizing the benefits of taking a landscape approach to GHG quantification. This paper gives an overview of approaches that have been taken to date for landscape-scale GHG quantification, covering both measurement and modelling and the reliance of one upon the other. The discussion covers ground-based measurement approaches for carbon stock changes in biomass and soils, methods for measuring GHG flux and the application of remote sensing techniques. Computational approaches for estimating carbon stock changes and GHG emissions are discussed, in addition to the use of more complex dynamic ecosystem models. This is followed by an analysis of some of the resources that are available for those wishing to do GHG quantification at the landscape scale in areas dominated by smallholders. This analysis is intended to provide an aid to funding agencies, government agencies, NGOs, academics and others. Information for this section comes from questionnaires distributed to selected resource developers.
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| 6. |
- Milne, Eleanor, et al.
(författare)
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Methods for the quantification of GHG emissions at the landscape level for developing countries in smallholder contexts
- 2013
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Ingår i: Environmental Research Letters. - : Institute of Physics: Open Access Journals / Institute of Physics (IoP). - 1748-9326 .- 1748-9318. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- Landscape scale quantification enables farmers to pool resources and expertise. However, the problem remains of how to quantify these gains. This article considers current greenhouse gas (GHG) quantification methods that can be used in a landscape scale analysis in terms of relevance to areas dominated by smallholders in developing countries. In landscape scale carbon accounting frameworks, measurements are an essential element. Sampling strategies need careful design to account for all pools/fluxes and to ensure judicious use of resources. Models can be used to scale-up measurements and fill data gaps. In recent years a number of accessible models and calculators have been developed which can be used at the landscape scale in developing country areas. Some are based on the Intergovernmental Panel on Climate Change (IPCC) method and others on dynamic ecosystem models. They have been developed for a range of different purposes and therefore vary in terms of accuracy and usability. Landscape scale assessments of GHGs require a combination of ground sampling, use of data from census, remote sensing (RS) or other sources and modelling. Fitting of all of these aspects together needs to be performed carefully to minimize uncertainties and maximize the use of scarce resources. This is especially true in heterogeneous landscapes dominated by smallholders in developing countries.
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