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

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

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

Rapid analysis of country-level mitigation potential from agriculture, forestry and other land uses in Mexico

- Total mitigation potential from the AFOLU sector was the highest in Chiapas (~13 Mt CO2eq) followed by Campeche (~ 8 Mt CO2eq). - 11 states (i.e. Oaxaca, Quintana Roo, Yucatan, Jalisco, Sonora, Veracruz, Durango, Chihuahua, Puebla, Michoacán and Guerrero) had a total AFOLU mitigation potential between 2.5 to 6.5 Mt CO2eq, other states had AFOLU mitigation potentials of less than 2 Mt CO2eq. - Crop mitigation potential was the highest in Veracruz, Jalisco and Michoacán; it was intermediate (between 0.4 to 0.6 Mt CO2eq) in the states of Chiapas, Sinaloa, Guanajuato, Mexico and Guerrero. Other states had crop mitigation potential less than 0.4 Mt CO2eq. - Livestock mitigation potential was the highest in Jalisco and Sonora and intermediate (between 0.4 to 0.8 Mt CO2eq) in the states of Puebla, Veracruz, Guanajuato, and Yucatan. Other states had livestock mitigation potentials of less than 0.3 Mt CO2eq. - The state-wide and total magnitude of mitigation was the highest from the FOLU sector. Per unit abatement, cost was also the highest in this sector. - If properly implemented, mitigation potentials on cropland can be realized with net benefits, compared to livestock and FOLU options, which involve net costs

Global N2O Dashboard

The target of our data collection was to compile an up-to-date database of as many field measurements of nitrous oxide (N2O) emissions from published experiments comparing unfertilized treatments with treatments fertilized with nitrogen (N) as possible. We used the database developed by Stehfest and Bouwman (2006) as a starting point but extended the number of descriptive parameter and measured N2O emission data as much as possible

Use of Empirical Tools/Calculatrs to Quantify GHG Emission from Agricultural Systems

The Climate Food and Farming (CLIFF) Research Network is an international research network that helps to expand young researchers' knowledge and experience working on climate change mitigation in smallholder farming. CLIFF provides grants for selected doctoral students to work with CGIAR researchers affiliated with the Standard Assessment of Mitigation Potential and Livelihoods in Smallholder Systems (SAMPLES) project. This presentation is Use of Empirical Tools/Calculatrs to Quantify GHG Emission from Agricultural Systems by Tek B. Sapkota, a scientist with the International Maize and Wheat Improvement Center

The effects of adequate and excessive application of mineral fertilizers on the soil

Fertilizers increase availability of essential plant nutrients in the soil and alter many chemical, biological and physical soil properties. Fertilizers lead to the accumulation of soil organic matter (SOM), but the excessive application of nitrogen fertilizers is deleterious to SOM, may contribute to nitrate pollution of freshwaters and emission of nitrous oxide – a greenhouse gas. Nitrogen fertilizers can also cause soil acidification. Phosphatic fertilizers may contribute to eutrophication of surface waters, and heavy metal impurities in these may contaminate soils. Balanced fertilization positively affects soil organic matter and soil biota; and in general soil microbial life is positively influenced

Agricultural sustainability under emerging climatic variability: the role of climate-smart agriculture and relevant policies in India

Global demand for agricultural products continues to grow while production resources are diminishing. Increasing climatic variability poses further challenges. Therefore, ensuring agricultural sustainability necessitates a transformation of the production system to make it more productive, inputefficient and to lower the environmental footprint. Such a transformation requires system-wide actions and considerable changes in governance, policies, and institutions. On this pretext, we examined if existing climate-smart agriculture (CSA) can enhance adaptation to and mitigation of climate change and overall food security in India. We found that CSA can substantially contribute towards climate change adaptation, mitigation, and food security. Mainstreaming CSA practices into development planning through CSVs would create mutual benefits by generating evidences based on CSAs at local level, thereby contributing to the design of local adaptation plans of action (LAPA) and further feed information into state and national action plans on climate change. Thus, we propose to mainstream CSA into development planning

Effects of catch crop type and root depth on nitrogen leaching and yield of spring barley

Catch crop root growth and nitrogen (N) uptake from both shallower and deeper soil layers is important for N management in arable farming system particularly in climates where excess winter precipitation induces N leaching. We simulated the root growth and biomass yield of three common catch crops [chicory (Cichorium intybus L.), fodder radish (Raphanus sativus L.) and perennial ryegrass (Lolium perenne L.)] and their effect on soil mineral N in different soil layers by using the FASSET model. The simulated results of catch crops root growth and mineral N in the soil profile were validated against two years (i.e. 2006 and 2007) of observations taken in Foulum and Flakkebjerg, Denmark. Fodder radish had the deepest root system and depleted N from deeper soil layers than chicory and ryegrass. The effect of these three catch crops on N leaching and grain yield of spring barley was simulated for 30 years using the FASSET model. The simulations showed that the system with ryegrass catch crop had a smaller amount of N leaching from 1 m depth than the system with other catch crops and without catch crops. However, estimated total N leached from 2 m soil depth was the smallest in the system with fodder radish followed by the system with chicory, indicating that these catch crops are capable for taking soil N also from below 1 m depth. On average, the system with fodder radish was estimated to decrease N leaching from 2 m depth by 79% compared with the system without catch crops, resulting in an average spring barley grain yield increase of 2%. Chicory and ryegrass correspondingly contributed to reducing N leaching from 2 m soil depths by 71 and 67%, but with the cost of decreasing spring barley yield by 3 and 5%, respectively, when compared with the system without catch crop. Termination of catch crop use slightly increased the spring barley yield, but also increased N leaching by about 17%. Inclusion of catch crop in the system increased the total N and C content in the soil in all cases but the increase was largest with ryegrass

Climate change mitigation options among farmers in South Asia

Agriculture in South Asia is highly vulnerable to climate change due to increasing variability in rainfall and rising temperatures leading to the incidence of extreme climatic events such as floods, droughts, heat/cold waves, and storms. Agriculture sector also contributes to the causes of climate change through the emission of greenhouse gasses (GHGs). Hence, adaptation-led mitigation measures are required to sustain agricultural productivity, farm income and reduce GHG emissions wherever possible. This study presents a systematic review of agriculture emission reduction opportunities with a particular focus on agricultural production systems in South Asia. Our review indicates that the adoption of better soil, water, nutrient management practices, and technologies has enormous potential to reduce GHG emissions from agriculture, thereby contributing to the mitigation of climate change. Many existing practices and technologies have the potential to improve both adaptation and mitigation in agriculture which can significantly contribute to complying with nationally determined contributions (NDCs) of South Asian countries. However, barriers to the adoption of GHG mitigating agricultural practices, mainly the financial and institutional barriers, need to be appropriately addressed to achieve the desired level of mitigation