Low-cost quantification of greenhouse gas emissions in smallholder agro-ecosystem: a comparative analysis of methods

Quantification of greenhouse gas (GHG) exchanges between agricultural field and the atmosphere is essential for understanding the contribution of various production systems to the total emissions, develop mitigation options and policies, raise awareness and encourage adoption. But, GHG quantification from smallholder agricultural landscape is challenging primarily because of the heterogeneity of production systems. Various methods have been developed over years to quantify GHG fluxes between agricultural ecosystem and atmosphere. In this paper, we reviewed and analysed the common methods with regard to their scale and precision of quantification, cost effectiveness, prospects and limitations focusing mainly on smallholder production systems. As most of the quantification methods depend on ground data and due to data deficit for smallholder systems, field measurement must be an essential part of GHG emission inventories under such systems. Chamber-based method is a principal approach for field level quantification under smallholder production system mainly because of its cost effectiveness, portability and adoptability under diverse field conditions. However, direct measurement of GHG for all mosaics of smallholder production landscape is impractical and therefore use of models becomes imperative. Here, selection of suitable models and their rigorous parameterization, calibration and validation under various production environments are necessary in order to obtain meaningful emission estimation. After proper validation, linking dynamic ecosystem models to geographic information system (GIS) helps estimating GHG emission within reasonable time and cost. Integration of different approaches such as chamber-based measurement to generate field data, simulation modelling by using empirical as well as process-based models coupled with use of satellite imagery may provide a robust estimate of GHGs emission than use of a single approach

Direct Nitrous Oxide Emissions From Tropical And Sub-Tropical Agricultural Systems : A Review and Modelling of Emission Factors

We acknowledge the financial support from the CGIAR Research Programs on Climate Change, Agriculture and Food Security (CCAFS). Grant ref. n. P25.Peer reviewedPublisher PD

gender and inorganic nitrogen what are the implications of moving towards a more balanced use of nitrogen fertilizer in the tropics

ABSTRACTFor agriculture to play a role in climate change mitigation strategies to reduce emissions from inorganic nitrogen (N) fertilizer through a more balanced and efficient use are necessary. Such strategies should align with the overarching principle of sustainable intensification and will need to consider the economic, environmental and social trade-offs of reduced fertilizer-related emissions. However, the gender equity dimensions of such strategies are rarely considered. The case studies cited in this paper, from India, Lake Victoria in East Africa and more broadly from sub-Saharan Africa (SSA), show that the negative externalities of imbalanced inorganic N use in high- and low-use scenarios impact more strongly on women and children. We examine, through a literature review of recent work in SSA, the relative jointness of intra-household bargaining processes in low N use scenarios to assess the degree to which they impact upon N use. We suggest that gender-equitable strategies for achieving more ba..

Site-Specific Nutrient Management: Implementation guidance for policymakers and investors

Site-Specific Nutrient Management (SSNM) provides guidance relevant to the context of farmers' fields. SSNM maintains or enhances crop yields, while providing savings for farmers through more efficient fertilizer use. By minimizing fertilizer overuse, greenhouse gas emissions can be reduced, in some cases up to 50%. SSNM optimizes the supply of soil nutrients over space and time to match crop requirements. SSNM increases crop productivity and improves efficiency of fertilizer use. SSNM mitigates greenhouse gases from agriculture in areas with high nitrogen fertilizer use. Incentives for adoption of SSNM depend strongly on fertilizer prices

Framework for rapid country-level analysis of AFOLU mitigation options

Mitigation in the agricultural sector is critical to meeting the 2 ̊C target set by the Paris Agreement. Recent analysis indicates that land-based mitigation can potentially contribute about 30% of the reduction is needed to reach the 2030 target. However, action to reduce emissions from the agricultural sector has lagged behind other sectors. Action and investment in agriculture have been constrained by a lack of policy-relevant and science-based methods estimating GHG emissions and mitigation potential that contribute to decision making. In this paper, we present a framework for a rapid country-level scientific assessment of emissions and mitigation potential from the agricultural, forestry and other land-use (AFOLU) sector. The framework sets targets for AFOLU mitigation based on local agro- environmental conditions, mitigation options best fitted for those conditions and stakeholder input. It relies on the use of simple models or tools to estimate emissions at the farm gate using a mix of Tier 1, Tier 2 and simple Tier 3 methods under baseline, business-as-usual (BAU) and mitigation scenarios. The mitigation potential of low-emissions agriculture options is determined relative to a baseline or BAU scenario. The framework also enables examining the likely level of implementation of low-emission options. This includes assessing the cost and additional benefits of applying the identified low- emission options across different jurisdictions of interest. The feasibility of these options, assessment of institutional capacity for scaling and identification of barriers and risks of adoption to identify priorities are also determined. This information is used by stakeholders and experts to develop a road map for implementation. Rapid assessment of national mitigation potentials can help countries to assess their Nationally Determined Contributions’ (NDC) targets and prioritize mitigation options for achieving the targets and monitor progress towards their achievement. Spatially explicit information helps countries plan implementation at subnational levels

Agricultural emissions reduction potential by improving technical efficiency in crop production

CONTEXT: Global and national agricultural development policies normally tend to focus more on enhancing farm productivity through technological changes than on better use of existing technologies. The role of improving technical efficiency in greenhouse gas (GHG) emissions reduction from crop production is the least explored area in the agricultural sector. But improving technical efficiency is necessary in the context of the limited availability of existing natural resources (particularly land and water) and the need for GHG emission reduction from the agriculture sector. Technical efficiency gains in the production process are linked with the amount of input used nd the cost of production that determines both economic and environmental gains from the better use of existing technologies. OBJECTIVE: To assess a relationship between technical efficiency and GHG emissions and test the hypothesis that improving technical efficiency reduces GHG emissions from crop production. METHODS: This study used input-output data collected from 10,689 rice farms and 5220 wheat farms across India to estimate technical efficiency, global warming potential, and emission intensity (GHG emissions per unit of crop production) under the existing crop production practices. The GHG emissions from rice and wheat production were estimated using the CCAFS Mitigation Options Tool (CCAFS-MOT) and the technical efficiency of production was estimated through a stochastic production frontier analysis. RESULTS AND CONCLUSIONS: Results suggest that improving technical efficiency in crop production can reduce emission intensity but not necessarily total emissions. Moreover, our analysis does not support smallholders tend to be technically less efficient and the emissions per unit of food produced by smallholders can be relatively high. Alarge proportion of smallholders have high technical efficiency, less total GHG emissions, and low emissions intensity. This study indicates the levels of technical efficiency and GHG emission are largely influenced by farming typology, i.e. choice and use of existing technologies and management practices in crop cultivation. SIGNIFICANCE: This study will help to promote existing improved technologies targeting GHG emissions reduction from the agriculture production systems

Financing climate change mitigation in agriculture: Assessment of investment cases

As with other sectors of the economy, agriculture should also contribute to meeting countries' emission reduction targets. Transformation of agriculture to low-carbon food systems requires much larger investments in low emission development options from global climate finance, domestic budgets, and the private sector. Innovative financing mechanisms and instruments that integrate climate finance, agriculture development budgets, and private sector investment can improve and increase farmers' and other value chain actors' access to finance while delivering environmental, economic, and social benefits. Investment cases assessed in this study provide rich information to design and implement mitigation options in agriculture through unlocking additional sources of public and private capital, strengthening the links between financial institutions, farmers, and agribusiness, and coordination of actions across multiple stakeholders. These investment cases expand support for existing agricultural best practices, integrate forestry and agricultural actions to avoid land-use change, and support the transition to market-based solutions

Re-assessing Nitrous Oxide Emissions from Croplands Across Mainland China

Reliable quantification of nitrous oxide emission is a key to assessing efficiency of use and environmental impacts of N fertilizers in crop production. In this study, N2O emission and yield were quantified with a database of 853 field measurements in 104 reported studies and a regression model was fitted to the associated environmental attributes and management practices from China’s croplands. The fitted emission model explained 48% of the variance in N2O emissions as a function of fertilizer rate, crop type, temperature, soil clay content, and the interaction between N rate and fertilizer type. With all other variables fixed, N2O emissions were lower with rice than with legumes and then other upland crops, lower with organic fertilizers than with mineral fertilizers. We used the subset of the dataset for rice - covering a full range of different typical water regimes, and estimated emissions from China’s rice cultivation to be 31.1 Gg N2O-N per year. The fitted yield model explained 35% of the variance in crop yield as a function of fertilizer rate, temperature, crop type, and soil clay content. Finally, the empirical models for N2O emission and crop yield were coupled to explore the optimum N rates (N rate with minimum N2O emission per unit yield) for combinations of crop and fertilizer types. Consequently, the optimum N application rate ranged between 100 kg N ha−1 and 190 kg N ha−1 respectively with organic and mineral fertilizers, and different crop types. This study therefore improved on existing empirical methods to estimate N2O emissions from China’s croplands and suggests how N rate may be optimized for different crops, fertilizers and site conditions

Quantifying opportunities for greenhouse gas emissions mitigation using big data from smallholder crop and livestock farmers across Bangladesh

Funding Information: The International Maize and Wheat Improvement Center (CIMMYT) carried out this work with support of the CGIAR research program on Climate Change, Agriculture and Food Security (CCAFS) and the Climate Services for Resilient Development (CSRD; https://ccafs.cgiar.org/research/projects/climate-services-resilient-development-south-asia ) for South Asia project supported by USAID . This work was also supported by the USAID and Bill and Melinda Gates Foundation (BMGF) supported Cereal Systems Initiative for South Asia (CSISA; https://csisa.org ). CCAFS' work is supported by CGIAR Fund Donors and through bilateral funding agreements. For details please visit https://ccafs.cgiar.org/donors . The views expressed in this paper cannot be taken to reflect the official opinions of CCAFS, USAID, or BMGF, and shall not be used for advertising. We sincerely acknowledge the input and support provided by various stakeholders in Bangladesh during stakeholder meetings. We are thankful to Robel Takele and Sanjay Pothireddy for graphics assistance.Peer reviewedPublisher PD

Spatially explicit database on crop-livestock management, soil, climate, greenhouse gas emissions and mitigation potential for all of Bangladesh

Acknowledgments: The International Maize and Wheat Improvement Center (CIMMYT) carried out this work with support of the CGIAR research program on Climate Change, Agriculture and Food Security (CCAFS) and the Climate Services for Resilient Development (CSRD; https://ccafs.cgiar.org/research/projects/climate-services-resilient-development-south-asia) for South Asia project supported by USAID. This work was also supported by the USAID and Bill and Melinda Gates Foundation (BMGF) supported Cereal Systems Initiative for South Asia (CSISA; https://csisa.org) CCAFS’ work is supported by CGIAR Fund Donors and through bilateral funding agreements. For details please visit https://ccafs.cgiar.org/donors. The views expressed in this paper cannot be taken to reflect the official opinions of CCAFS, USAID, or BMGF, and shall not be used for advertising.Peer reviewedPublisher PD