Development of methane emission factors for Indian paddy fields and estimation of national methane budget

Emission of greenhouse gases due to anthropogenic activities: an environmental assessment from paddy rice fields

Paddy rice fields (PRFs) are a potent source of global atmospheric greenhouse gases (GHGs), particularly CH₄ and CO₂. Despite socio-environmental importance, the emission of GHGs has rarely been measured from Haryana agricultural fields. We have used new technology to track ambient concentration and soil flux of GHGs (CH₄, CO₂, and H₂O) near Karnal's Kuchpura agricultural fields, India. The observations were conducted using a Trace Gas Analyzer (TGA) and Soil Flux Smart Chamber over various parts, i.e., disturbed and undisturbed zone of PRFs. The undisturbed zone usually accounts for a maximum ambient concentration of ~ 2434.95 ppb and 492.46 ppm of CH₄ and CO₂, respectively, higher than the average global concentration. Soil flux of CH₄ and CO₂ was highly varied, ranging from 0.18 to 11.73 nmol m^-2 s^-1 and 0.13-4.98 μmol m^-2 s^-1, respectively. An insignificant correlation was observed between ambient concentration and soil flux of GHGs from PRFs. Waterlogged (i.e., irrigated and rain-fed) soil contributed slightly lower CH₄ flux to the atmosphere. Interestingly, such an agricultural field shows low CO₂ and CH₄ fluxes compared to the field affected by the backfilling of rice husk ash (RHA). This article suggests farmers not mix RHA to increase soil fertility because of their adverse environmental effects. Also, this study is relevant in understanding the GHGs' emissions from paddy rice fields to the atmosphere, their impacts, and mitigating measures for a healthy ecosystem.

Biogenic link to the recent increase in atmospheric methane over India

Methane (CH₄) is a prominent Greenhouse Gas (GHG) and its global atmospheric concentration has increased significantly since the year 2007. Anthropogenic CH₄ emissions are projected to be 9390 million metric tonnes by 2020. Here, we present the long-term changes in atmospheric methane over India and suggest possible alternatives to reduce soil emissions from paddy fields. The increase in atmospheric CH₄ concentrations from 2009 to 2020 in India is significant, about 0.0765 ppm/decade. The Indo-Gangetic Plains, Peninsular India and Central India show about 0.075, 0.076 and 0.074 ppm/decade, respectively, in 2009-2020. Seasonal variations in CH₄ emissions depend mostly on agricultural activities and meteorology, and contribution during the agricultural intensive period of Kharif-Rabi (i.e., June-December) is substantial in this regard. The primary reason for agricultural soil emissions is the application of chemical fertilizers to improve crop yield. However, for rice farming, soil amendments involving stable forms of carbon can reduce GHG emissions and improve soil carbon status. High crop production in pot culture experiment resulted in lower potential yield-scaled GHG emissions in rice with biochar supplement. The human impact of global warming induced by agricultural activities could be reduced by using biochar as a natural solution.

Greenhouse gas emission from rice fields: a review from Indian context

Agricultural soil acts as a source and sink of important greenhouse gases (GHGs) like methane (CH4), nitrous oxide (N2O), and carbon dioxide (CO2). Rice paddies have been a major concern to scientific community, because they produce the threatening and long-lasting GHGs mainly CH4 and N2O. Around 30% and 11% of global agricultural CH4 and N2O, respectively, emitted from rice fields. Thus, it is urgent to concurrently quantify the fluxes of CH4 and N2O to improve understanding of both the gases from rice fields and to develop mitigation strategies for upcoming climate change reduction. An effort is being made in this review to discuss exclusively the emission of CH4 and N2O under normal and controlled conditions in different locations of India and also addresses the current synthesis of available data on how field and crop management activities influence CH4 and N2O emissions in rice fields. Making changes to conventional crop management regimes could have a significant impact on reducing GHG emissions from rice field. Environmental and agricultural factors related to soil could be easily altered by management practices. So, knowing the mechanism of CH4 and N2O production and release in the rice field and factors controlling the emissions is fundamental to develop well-organized strategies to reduce emissions from rice cultivated soil. This will help the regulatory bodies or policy makers to formulate adequate policies for agricultural farmers to refine the GHG emissions as well as minimize the global climate change.

75th Foundation Day of CSIR-National Physical Laboratory: Celebration of Achievements in Metrology for National Growth

The CSIR-National Physical Laboratory (CSIR-NPL), the National Metrology Institute (NMI) of India, is a premier laboratory, founded on January 04, 1947, under the umbrella of Council of Scientific and Industrial Research (CSIR), New Delhi, Government of India, by an Act of Parliament. It has now completed 74 glorious years after inception and entered into its 75th year, i.e. Platinum Jubilee Year. To commemorate its 75th Foundation Day, the CSIR-NPL organized a National Metrology Conclave (NMC) on January 04, 2021. On this auspicious occasion, the Honourable Prime Minister of India, Mr. Narendra Modi dedicated the National Atomic Timescale and Bhartiya Nirdeshak Dravya (BND^®)—CRMs to the nation. He also laid the foundation stone of National Environmental Standard Laboratory. He addressed the august gathering in the gracious presence of Honourable Union Minister of Science and Technology, Dr. Harsh Vardhan. Honourable Prime Minister inspired, motivated and appreciated the strides made by Indian Scientists for nation building, especially the role of CSIR-NPL and impact of metrology for self-reliant India. Honourable Minister, Dr. Harsh Vardhan, inaugurated the exclusively designed poster gallery, displaying accomplishments and importance of metrology in the CSIR-NPL campus and released a book entitled, “Metrology for Inclusive Growth of India”. Several of the world metrology leaders also presented their visions, in the NMC, on the role of metrology in societal and industrial growth through online virtual platform. The main emphasis was placed on the importance and impact of the metrology in the success of several initiatives of Government of India, namely ‘AtmaNirbhar Bharat’ (Self-Reliant India), ‘Make in India’, ‘Digital India’, ‘Skill India’, ‘Vocal for Local’, etc. During all these years, the journey of the CSIR-NPL has been wonderful, splendid and magnificent on several aspects of celebrations, pride, recognition, global visibility and its services for the national cause. It has achieved many milestones, developed technologies of national eminence, organised many memorable events, successfully participated in various national missions’ time to time and published considerable amount of literature for knowledge generation in the form of research papers, patents, copyrights, books, monographs, technical peers, Calibration and Measurement Capabilities (CMCs) and study reports, etc. The successful journey of these glorious years though looks easy, simple, normal and customary but in actual sense, lot of pain staking efforts, huge work, vicissitudes are behind all these accomplishments. The glimpses of the journey of CSIR-NPL from its inception to recently held NMC and the excerpts of addresses made by the dignitaries are also summarized in detail in this article.

Re-estimating methane emissions from Chinese paddy fields based on a regional empirical model and high-spatial-resolution data

Quantifying methane (CH₄) emissions from paddy fields is essential for evaluating the environmental risks of the paddy rice production system, and improving the accuracy of CH₄ modeling is a key issue that needs to be addressed. Based on a database containing 835 field measurements, both single national and region-specific models were established to estimate CH₄ emissions from paddy fields considering different environmental factors and management patterns using 70% of the measurements. The remaining 30% of the measurements were then used for model evaluation. The performance of the region-specific model was better than that of the single national model. The region-specific model could simulate CH₄ emissions in an unbiased manner with R² values of 0.15-0.70 and efficiency values of 11-60%. The paddy rice type, water regime, organic amendment, latitude, and soil characteristics (pH and bulk density) were identified as the main drivers in the models. By inputting the high-resolution spatial data of these drivers into the established model, the CH₄ emissions from China's paddy fields were estimated to be 4.75 Tg in 2015, with a 95% confidence interval of 4.19-5.61 Tg. The results indicated that establishing and driving a region-specific model with high-resolution data can improve the estimation accuracy of CH₄ emissions from paddy fields.

Cost-effective opportunities for climate change mitigation in Indian agriculture

Long-term changes in average temperatures, precipitation, and climate variability threaten agricultural production, food security, and the livelihoods of farming communities globally. Whilst adaptation to climate change is necessary to ensure food security and protect livelihoods of poor farmers, mitigation of greenhouse gas (GHG) emissions can lessen the extent of climate change and future needs for adaptation. Many agricultural practices can potentially mitigate GHG emissions without compromising food production. India is the third largest GHG emitter in the world where agriculture is responsible for 18% of total national emissions. India has identified agriculture as one of the priority sectors for GHG emission reduction in its Nationally Determined Contributions (NDCs). Identification of emission hotspots and cost-effective mitigation options in agriculture can inform the prioritisation of efforts to reduce emissions without compromising food and nutrition security. We adopted a bottom-up approach to analyse GHG emissions using large datasets of India's 'cost of cultivation survey' and the '19th livestock census' together with soil, climate and management data for each location. Mitigation measures and associated costs and benefits of adoption, derived from a variety of sources including the literature, stakeholder meetings and expert opinion, were presented in the form of Marginal Abatement Cost Curves (MACC). We estimated that by 2030, business-as-usual GHG emissions from the agricultural sector in India would be 515 Megatonne CO2 equivalent (MtCO2e) per year with a technical mitigation potential of 85.5 MtCO2e per year through adoption of various mitigation practices. About 80% of the technical mitigation potential could be achieved by adopting only cost-saving measures. Three mitigation options, i.e. efficient use of fertilizer, zero-tillage and rice-water management, could deliver more than 50% of the total technical abatement potential.

Carbon footprint and agricultural sustainability nexus in an intensively cultivated region of Indo-Gangetic Plains

Green Revolution led to an unprecedented increase in world food production but with a significant carbon footprint raising concerns about its sustainability. With the rising global population and the need to produce more food, the farming systems will have to be sustainable. To identify farming practices that increase yield with minimum environmental cost, it is imperative to quantify the environment footprint of different technologies. The present study quantified the impact of Green Revolution technologies on the carbon footprint of intensive crop production systems, mainly rice-wheat in an agriculturally important region of Indo-Gangetic Plains. The results revealed the overriding importance of groundwater irrigation and fertilizer use in determining the carbon footprint of crop production, and underpin the opportunities for their mitigation. Intensification of agriculture resulted in ~2.5 fold increase in food grain production and 3-fold increase in emission of greenhouse gases (GHGs) during 1980 to 2015. Carbon sustainability of food grain production declined with time indicating that energy use efficiency is decreasing; the greatest decline being in rice followed by wheat and negligible in maize. Options for mitigating environment footprint of food grain production included partially replacing area under rice with other less water requiring crops, improving irrigation water productivity and pumping efficiency, and increasing fertilizer use efficiency. Maize with low global warming potential and high C sustainability appeared a viable option for diversification. The implementation of these mitigation measures can reduce environment footprint by 46%. Preventing crop residue burning will not only offset the associated GHG emissions (6266 Gg yr^-1) but can also improve soil health if returned to the soil. Intensification of agriculture has co-benefit of C sequestration in soil, which besides offsetting emissions by ~10% is an important determinant of soil quality and sustainability.

Greenhouse gas emissions from agricultural food production to supply Indian diets: Implications for climate change mitigation

Agriculture is a major source of greenhouse gas (GHG) emissions globally. The growing global population is putting pressure on agricultural production systems that aim to secure food production while minimising GHG emissions. In this study, the GHG emissions associated with the production of major food commodities in India are calculated using the Cool Farm Tool. GHG emissions, based on farm management for major crops (including cereals like wheat and rice, pulses, potatoes, fruits and vegetables) and livestock-based products (milk, eggs, chicken and mutton meat), are quantified and compared. Livestock and rice production were found to be the main sources of GHG emissions in Indian agriculture with a country average of 5.65 kg CO₂eq kg^-1 rice, 45.54 kg CO₂eq kg^-1 mutton meat and 2.4 kg CO₂eq kg^-1 milk. Production of cereals (except rice), fruits and vegetables in India emits comparatively less GHGs with <1 kg CO₂eq kg^-1 product. These findings suggest that a shift towards dietary patterns with greater consumption of animal source foods could greatly increase GHG emissions from Indian agriculture. A range of mitigation options are available that could reduce emissions from current levels and may be compatible with increased future food production and consumption demands in India.