Differences In Greenhouse Gas Emissions Research Articles

Gypsum and structure lime amendments in boreal agricultural clay soils: Do climate emissions compromise water quality benefits?

We examine cost-effectiveness and social net benefits of using soil amendments, gypsum and structure lime, in reducing phosphorus loading while accounting for the climate emissions from both amendments. Recent field experiments and large-scale pilots in Finland and Sweden suggest that both gypsum and structure lime improve soil structure and can reduce total P loading from clayey fields but differ as soil amendments. While gypsum does not change soil pH, structure lime helps to adjust it to a desired level. Drawing on literature, gypsum is postulated to reduce both dissolved (25%) and particulate losses (50%) of phosphorus, while structure lime is postulated to reduce only particulate phosphorus (40%). Life-cycle analysis is applied to determine greenhouse gas emissions from both soil amendments. We examine 5 and 10 years impacts on phosphorus loss by choosing doses and their timing accordingly. Both amendments provide the highest water quality benefits on erodible soils or soils with high soil phosphorus. Accounting for climate issues drastically changes the picture. Greenhouse gas emissions from gypsum production are 14.43 kgCO2e ha-1, and those from structure lime from pristine materials are 1837 kgCO2e ha-1. Cost-effectiveness of P load reduction including carbon price of GHG emissions is 59 € kg-1P for gypsum and 122 € kg-1P for structure lime. At the national level (application to 0.54 Mha), differences in greenhouse gas emissions without soil emissions are huge and in favour of gypsum (0.048 Mt and 1.04 Mt). Structure lime from recycled zero-emission materials performs well but its supply is very limited.

National Greenhouse Gas Emission Reduction Potential from Adopting Anaerobic Digestion on Large-Scale Dairy Farms in the United States.

Waste-to-energy systems can provide a functional demonstration of the economic and environmental benefits of circularity, innovation, and reimagining existing systems. This study offers a robust quantification of the greenhouse gas (GHG) emission reduction potential of the adoption of anaerobic digestion (AD) technology on applicable large-scale dairy farms in the contiguous United States. GHG reduction estimates were developed through a robust life cycle modeling framework paired with sensitivity and uncertainty analyses. Twenty dairy configurations were modeled to capture important differences in housing and manure management practices, applicable AD technologies, regional climates, storage cleanout schedules, and methods of land application. Monte Carlo results for the 90% confidence interval illustrate the potential for AD adoption to reduce GHG emissions from the large-scale dairy industry by 2.45-3.52 MMT of CO2-eq per year considering biogas use only in renewable natural gas programs and as much as 4.53-6.46 MMT of CO2-eq per year with combined heat and power as an additional biogas use case. At the farm level, AD technology may reduce GHG emissions from manure management systems by 58.1-79.8% depending on the region. Discussion focuses on regional differences in GHG emissions from manure management strategies and the challenges and opportunities surrounding AD adoption.

Greenhouse gas emissions and their driving factors among different flowering Chinese cabbage (Brassica campestris L.) varieties.

Crop cultivars have an influence on greenhouse gas (GHG) emissions, and there is variation between varieties. However, there are few reports available on the differences in GHG emissions and their driving factors among vegetable varieties. In this study, we conducted a field experiment to examine the variances in GHG emissions and their contributing factors among eight flowering Chinese cabbage varieties (considering growth period, leaf shape, and colour). The results showed significant differences in GHG emissions within varieties; early-maturing varieties exhibited GHG by 25.6% and 15.3%, respectively, when compared to mid- and late-maturing varieties. Among the different leaf types and color classifications, light-colored and sharp-leafed varieties had the lower global warming potential (GWP) overall. Cumulative CO2 emissions were influenced by leaf SPAD values and biomass, while cumulative N2O emissions were driven mainly by stem thickness, carbon accumulation, leaf SPAD values, and biomass. In summary, the selection of light-colored varieties with pointed leaves and shorter growth periods in actual production contributed positively to the reduction of carbon emissions from flowering Chinese cabbage production. Through efficient variety screening, this study provides a win-win strategy for achieving efficient vegetable production while also addressing the global climate challenge.

Characterizing urban GHG emissions based on land-use change—A case of Airport New City

Measuring greenhouse gas (GHG) emissions across different types of land is essential for urban planning during the transition to low-carbon cities. Urban land identification, based on remote sensing images and points of interest (POIs), has the potential to narrow down the statistical unit, helping achieve spatial visualization of GHG emissions below the city level and distinguish emission characteristics of different land-use types. Considering land type as a classification standard for GHG emissions, we constructed the modified STRIPAT-PLS model by identifying land-use types, reconstructing land-use GHG emissions (LUGEs) inventory, and extracting driving indexes, which calculated driving force and LUGEs that were missed in historical years. It deepened the depth and precision of GHG emissions research and provided a reference for LUGE reduction and land management below the city level where missing historical data on GHG inventories. The results showed that: 1) the modified STRIPAT-PLS model achieved a simulation accuracy of 94.9%, demonstrating the effectiveness of our research approach in depicting GHG emissions across different land-use types. 2) Land scale, socio-economic development, and industrial development were key factors that impacted agricultural land, residential land, and airport respectively. 3) Airport was the most significant carbon contributor, while industrial witnessed the highest growth in emission intensity; 4) the spatial analysis indicated decreasing differences in GHG emissions and an overall increase in emission intensity. In addition, the research proposed emission reduction priorities and strategies for each land type to promote low-carbon goals in airport cities.

Differences in greenhouse gas emissions and microbial communities between underground and conventionally constructed wastewater treatment plants

Large quantities of greenhouse gases (GHGs) are emitted into the atmosphere during wastewater treatment. In this study, GHG and microbial samples were collected from four wastewater treatment plants (WWTPs), and their differences and relationships were assessed. The study showed that, compared with conventionally constructed WWTPs, well-established gas collection systems in underground WWTPs facilitate comprehensive collection and accurate accounting of GHGs. In aboveground WWTPs, capped anoxic ponds promote methane production releasing it at 2–8 times the rate of uncapped emissions, in contrast to nitrous oxide emissions. Moreover, a stable subsurface environment allows for smaller fluctuations in daily GHG emissions and higher microbial diversity and abundance. This study highlights differences in GHG emission fluxes and microbial communities in differently constructed WWTPs, which are useful for control and accurate accounting of GHG emissions.

Scenario analysis of the eco-efficiency for municipal solid waste management: A case study of 211 cities in western China

Mitigating greenhouse gas (GHG) emissions is vital for creating sustainable municipal solid waste management systems (MSWMS). In this study, we constructed an MSWMS considering recycling and carried out GHG emission accounting for MSWMS in western China from 2012 to 2021 based on the IPCC mass balance (MB) method. Then, we modeled the emission reduction potentials and economic benefits under different scenarios for 211 prefectural and county-level cities. We formed an eco-efficiency analysis framework that can be used to explore the sustainable development mode. Results revealed that: (1) Emissions from the western region's municipal solid waste (MSW) disposal exhibit an inverted “U” pattern, increasing at an annual rate of about 1.3 % since 2012, peaking in 2019, and then decreasing at rates of 14.4 % and 10.6 %. (2) The GHG emissions show a spatial pattern of decreasing evolution from east to west and south to north, and the provincial-municipal level shows different trends. (3) The SB3 scenario (optimization of landfill gas power generation technology) was the most ecologically efficient in 43 % of the western cities, followed by SB4 (33 %) and SA3 (24 %). (4) The development of integrated urban domestic waste management strategies by the three-level scenarios derived from this study will help local governments achieve the goal of sustainable urban development. Clarifying the differences in GHG emissions and eco-efficiency among cities will help provide policy recommendations for regions with similar characteristics to explore technically applicable, economically affordable implementation paths for city management according to local conditions.

Zelena perspektiva općeg i namjenskog kontejnerskog prijevoza od Azije do sjevernog Jadrana

Intermodal transport is often touted as an environmentally sustainable mode of transport, especially when considering its share of the total supply chain. This article addresses the topical and sensitive issue of supply chain assessment in terms of the carbon footprint and energy efficiency of external transportation from the point of production to the customer. The long transportation distances overseas and the variety of operational sea container services result in significant variations in delivery times from Asian markets. In addition, disruptive events such as the Covid-19 pandemic and the Ukraine conflict have led to longer transportation times and lower reliability of various maritime services. The study examines the variety of existing direct container services from Asia to the Northern Adriatic. In addition to the two direct container services already established, another dedicated container service has been established primarily to serve a large retail chain in the European market. The “newly established” container service is characterised by its limited port coverage and the use of relatively small container ships with a maximum capacity of 5.500 TEU. The comparisons between the services highlight the differences in transport time and greenhouse gas (GHG) emissions, as well as the energy efficiency of container transport. The study empirically confirms the widespread assumption that larger and modern container ships offer environmental benefits, provided that cargo space is used efficiently and ship operators adopt slow steaming. However, the study also highlights the significant differences in GHG emissions between different services and emphasises the need for more comprehensive information and awareness among cargo owners to design sustainable supply chains.

Characteristics of greenhouse gases emission from wastewater treatment plants operation in China (2009–2016): A case study using operational data integrated method (ODIM)

The reduction of greenhouse gas (GHG) and achieving carbon neutrality in wastewater treatment plants (WWTPs) has gained significant research attention due to China's dual carbon goals. However, the temporal and spatial characteristics of GHG emissions and the reduction potential regarding GHG emissions from WWTPs in China remain significant uncertainties. This study aims to evaluate GHG emissions characteristics over the years using a set of computational methods, and assess the reduction potential from WWTPs based on operational parameters and economic considerations. This study evaluated GHG emissions of more than 1000 WWTPs in China from 2009 to 2016 using operational data integrated methods (ODIM) and emission factors method to estimate direct N2O, direct CH4 emissions and indirect electricity-induced GHG emissions. GHG emissions were analyzed from temporal, spatial and operational parameters aspects. Besides, data envelopment analysis (DEA) was used to analyze WWTPs' efficiency in 2017. The results show that GHG emissions increased from 8163 Gg in 2009 to 14,008 Gg in 2016, with emission intensity maintained in the range of 0.266 kgCO2-eq/m3 to 0.298 kgCO2-eq/m3. Indirect GHG emissions from electricity consumption were the main source, which accounted for 72%–80% of the total emissions. Remarkable differences in GHG emissions were observed among six different regions and 31 provinces. WWTPs with AAO process, large treatment capacity, high loading, low influent COD concentration and high effluent NH3–N concentration contributed to lower GHG emission intensity. Furthermore, the treatment process was correlated significantly with GHG emission intensity, whereas influent COD concentration had the least influence from regression analysis results. DEA evaluation indicated that the average efficiency score in 2016 was only up to 0.240 with 27 WWTPs reaching a full efficiency score (efficiency score above 1.000). Electricity consumption and ammonia nitrogen reduction were the most prioritized indicators which could be changed by −53.55% and 592.60%, respectively, to achieve a full efficiency score. The study provides a valuable reference for policymakers and stakeholders to reduce GHG emissions and achieve carbon neutrality in WWTPs, thus contributing to the larger goal of reducing GHG and mitigating climate change.

Life cycle assessment of shared electric bicycle on greenhouse gas emissions in China

Following the bike-sharing system, the shared electric bicycle (SEB) is experiencing explosive growth in China as an emerging shared transportation mode. While shared transportation has long been linked to energy conservation and reducing emissions, a major problem facing SEB is whether it can reach the goal of greenhouse gas (GHG) reduction. This paper aims to evaluate GHG emissions at each stage of production, operation, and disposal of the SEB using life cycle assessment of GHG emissions. We also compared the differences in GHG emissions between the recycling incineration scenario (H1) and the recycling degradation scenario (H2) in the disposal stage. The GHG emissions of SEB in the production and operation stages were found to be 379.6173 kg CO2-eq and 183.4663 kg CO2-eq, respectively. However, the GHG emission reduction in the use stage was 1049.8374 kg CO2-eq. Thus, the net GHG reduction in the life cycle of the SEB was 487.3923 kg CO2-eq. (H1) and 433.9215 kg CO2-eq. (H2), respectively, indicating that SEB had a green effect. Non-recyclable parts of SEB will take 48 years to degrade in landfills in the H2 scenario. The GHG emission thresholds for SEB were further discussed. When the average daily turnover rate of SEB was less than 4 and its operation day was less than 479, SEB would not be able to achieve the goal of GHG reduction in the whole life cycle, with the riding statistics remaining unchanged. Finally, some advice for practical issues of electric bicycle sharing in energy conservation and GHG reduction were presented in response to the results.

Food Carbon Literacy: A Definition and Framework Exemplified by Designing and Evaluating a Digital Grocery List for Increasing Food Carbon Literacy and Changing Behavior

Public knowledge about the differences in greenhouse gas emissions caused by the production and transportation of different kinds of food are generally low. People with an interest in choosing food with low greenhouse gas emissions must therefore either increase this “food carbon literacy” or be provided with such information when they decide what food to buy. Research about this specific kind of food literacy is, however, scarce, lacking both well-defined terminology and interventions attempting to increase food carbon literacy. In this paper we provide a framework for future research in the area by defining “food carbon literacy”, serving as a starting point for categorizing, comparing, and generalizing future research findings. Drawing on previous work on other kinds of literacies, we distinguish between (1) food carbon literacy, (2) food product carbon literacy, (3) food handling carbon literacy, and (4) financial food carbon literacy. We have furthermore developed and tested a digital behavior change intervention in the form of a digital grocery list used on mobile phones. The list works as other digital grocery shopping lists, but also displays the CO2e footprint of the food added to the list, thereby enabling the user to change products at the planning stage and increase their food carbon literacy. It was tested on a group of 38 people for a duration of 2 weeks. The goals of the pilot study were to investigate quantitatively whether such a tool would increase food carbon literacy, and to investigate qualitatively how such a tool could be used and designed. The results show a strong increase in food carbon literacy for food the respondents had added to their grocery lists, but also for food that had not been added to their lists, indicating a generalization of the knowledge. Finally, we provide implications for the design of such systems, based on the qualitative evaluation.

The Influence of Different Degradation Characteristics on the Greenhouse Gas Emissions of Silicon Photovoltaics: A Threefold Analysis

The environmental footprint of photovoltaic electricity is usually assessed using nominated power or life cycle energy output. If performance degradation is considered, a linear reduction in lifetime energy output is assumed. However, research has shown that the decrease in energy output over time does not necessarily follow a linear degradation pattern but can vary at different points in the module’s lifetime. Further, photovoltaic modules follow different degradation patterns in different climate zones. In this study, we address the influence of different degradation aspects on the greenhouse gas (GHG) emissions of PV electricity. Firstly, we apply different non-linear degradation scenarios to evaluate the GHG emissions and show that the differences in GHG emissions in comparison to a linear degradation can be up to 6.0%. Secondly, we use the ERA5 dataset generated by the ECMWF to calculate location-dependent degradation rates and apply them to estimate the location-specific GHG emissions. Due to the reduction in lifetime energy output, there is a direct correlation between the calculated degradation rate and GHG emissions. Thirdly, we assess the impact of climate change on degradation rates and on the respective GHG emissions of photovoltaic electricity using different climate change scenarios. In a best-case scenario, the GHG emissions are estimated to increase by around 5% until the year 2100 and by around 105% by 2100 for a worst-case scenario.

Integrated Carbon Footprint and Economic Performance of Five Types of Dominant Cropping Systems in China’s Semiarid Zone

Crop production requires large areas of land and makes an important contribution to greenhouse gas emissions. Cleaner production of all crop types could be of great significance to realizing carbon neutrality as soon as possible. The present study adopted life cycle assessment (LCA) combined with the profit accounting method of input-output to compare the differences in greenhouse gas emissions in the entire life cycle of apple (Malus pumila Mill.), grain maize (Zea mays L.), wheat (Triticum aestivum L.), silage maize (Zea mays L.), and alfalfa (Medicago sativa Linn.) production in eastern Gansu Province with three functional units, including per ha of land, per ton of product, and per 10,000 yuan of output value. The results showed that apple had the largest carbon footprint per ha. Wheat had the largest carbon footprint per ton of product and per 10,000 yuan output. The results of LCA inventory sensitivity analysis showed that the main sources of greenhouse gas emissions for all crops were the production process of agricultural materials such as chemical fertilizer, machinery, and agricultural film. In particular, the excessive input of chemical fertilizer was the driving factor resulting in greenhouse gas emissions. Based on the study results, this paper also puts forward certain suggestions on the future land use of the cropping systems in the study area.

Effect of dissolved organic matter (DOM) on greenhouse gas emissions in rice varieties

Rice paddy fields are important sources of atmospheric methane (CH4) and nitrous oxide (N2O). Dissolved organic matter (DOM) is one of the most reactive organic matter fractions in the soil. However, the relationships between greenhouse gas emissions and DOM properties associated with different rice varieties in paddy fields are unclear. Here, a two-year field experiment was conducted to investigate the relationships between DOM characteristics and microbial gene abundance on CH4 and N2O emissions in seven rice varieties. The dissolved organic carbon, dissolved sugar, and NH4-N and NO3-N contents were positively correlated with CH4 and N2O emissions, and dissolved phenol was negatively correlated with CH4 and N2O emissions. Fourier transform infrared (FTIR) and three-dimensional fluorescence (EEM) spectroscopy analysis further indicated that DOM includes more O-H and CO phenol and protein content, of which tryptophan-like and tyrosine-like protein materials were positively correlated with CH4 and N2O emissions. In addition, CH4 and N2O emissions were significantly correlated with microbial functional genes (mcrA, pmoA, AOA, AOB, nirS, and nosZ). The redundancy analysis indicated that dissolved organic carbon, dissolved sugar, NH4-N, NO3-N, and tyrosine-like and tryptophan-like proteins in the DOM were significantly correlated with soil microbial functional gene abundance, suggesting that DOM could regulate CH4 and N2O emissions by influencing microbial abundance. The rice variety with lower greenhouse gas emissions (YY 1540) had the highest yield. These results demonstrated that the differences in greenhouse gas emissions among different rice varieties were dependent on DOM properties and microbial abundance, providing a theoretical basis for mitigating greenhouse gas emissions in rice paddy fields.

Cooperation between specialized livestock and crop farms can reduce environmental footprints and increase net profits in livestock production

The rapid specialization of livestock production in China has contributed to spatially decoupled crop and livestock production, leading to various environmental pollution issues. Some regional agro-environmental policies have recently promoted the coupling of specialized crop and livestock farms through cooperation. However, the environmental and economic performances of such cooperation remain unclear. This study investigated multiple environmental footprints of two contrasting production systems: cooperative crop-livestock systems (CCLS) and decoupled specialized livestock systems (DSLS), using survey data of 87 ruminant farms in Northwest China. Results show that farms in CCLS had lower net greenhouse gas (GHG) emissions (12–29%), lower reactive nitrogen (Nr) emissions (21–40%), lower phosphorus footprints (PF) (41–54%), and used less cropland (24–31%) per kg animal product, compared to those in DSLS. The large differences in GHG emissions between the two systems were mainly related to enteric fermentation and resource production (used for feed production). The differences in Nr emissions and PF were mainly related to manure management. Net profits per kg animal product were higher in CCLS (13–35%) than in DSLS, and most profits originated from lower purchasing costs of feed and young livestock. Net profits and environmental footprints were negatively correlated, suggesting an environmental and economic win-win situation for CCLS. The possible obstacles to recoupling specialized crop and livestock farms through cooperation have been discussed, including farm size, contract stability, and local policies. Our study provides science-based evidence to support policymakers and specialized farms to close nutrient loops between crop and livestock production sectors through regional cooperation.

Thickness of peat influences the leaching of substances and greenhouse gas emissions from a cultivated organic soil

The off-site effects of agricultural organic soils include the leaching of N, P, and organic carbon (OC) to watercourses and CO2, CH4, and N2O emissions into the atmosphere. The aim of this study was to quantify how the thickness of organic layers affects these loads. A 19.56-ha experimental field drained by subsurface pipes was established in Ruukki, northwestern Finland. Three plots had a 60–80 cm-thick sedge peat layer and three others had a thickness of 20 cm or less. The drainage pipes lie in mineral soil that, in this field, contains sulfidic material. This study documents the experimental settings and reports on the leaching of substances in the first two years, as well as CO2, CH4 and N2O emissions during eight weeks in one summer. Total N (TN) and OC loads were higher from the thicker peat plots. The mean TN loads during a hydrological year were 15.4 and 9.2 kg ha−1 from the thicker and thinner peat plots, respectively, with organic N representing 36% of TN load. Total P (TP) load averaged 0.27 kg ha−1 yr−1. Dissolved P load represented 63 and 36% of TP in the thicker peat area and only 23 and 13% in the thinner peat area, and was thus increased upon peat thickness. These N and P loads through the subsurface drainage system represented roughly 83% of TN and 64% of TP loads from this field. There were no clear differences in greenhouse gas emissions among the plots during the eight-week monitoring period. Slowly oxidizing sulfide in the subsoil resulted in annual leaching of 147 kg S ha−1, almost ten times that of non-sulfidic soils. Our first results emphasize the effect of the peat thickness on the leaching of substances and warn about considering all organic soils as a single group in environmental assessments.

On the short-term response of soil greenhouse gas emissions in Cunninghamia lanceolata forest to the expansion and eradication of Phyllostachys edulis

Objective With an investigation of the effects of expansion and eradication of Phyllostachys edulis (moso bamboo) on soil greenhouse gas emission flux and soil physical and chemical properties in Cunninghamia lanceolata (Chinese fir) forest, this paper is aimed to provide theoretical basis for the scientific management of moso bamboo expansion. Method Short-term in-situ monitoring was carried out of the soil greenhouse gas flux in pure moso bamboo forest (BF), Chinese fir released forest upon the eradication of moso bamboo from the Chinese fir forest mixed with moso bamboo (RF), moso bamboo and Chinese fir mixed forest (MF), and pure Chinese fir forest (CF) using a static chamber gas chromatography method. Result The expansion and eradication of moso bamboo increased the soil CO2 emission flux, which were 827.55, 485.09, 374.33 and 300.44 mg·m−2·h−1 for BF, RF, MF and CF respectively whereas the soil N2O emission flux were 120.86, 98.03, 82.89 and 70.23 µg·m−2·h−1, and the soil CH4 absorption flux were 155.38, 145.77, 135.26 and 119.62 µg·m−2·h−1. The soil temperature decreases from MF (19.77 ℃) to RF (18.72 ℃), BF (18.49 ℃) and CF (18.32 ℃) while the soil moisture content decreases from RF (27.32%) to CF (23.04%), BF (18.67%) and MF (16.36%). In these four different stands, the soil CO2 and N2O emission fluxes and CH4 absorption fluxes were significantly positively correlated with soil temperature and moisture content (P＜0.01) with consistent dynamic changes and had a positive correlation with soil inorganic nitrogen ( \begin{document}$ {\rm{NH}}^{+}_{4}\text{-}{\rm{N}} $\end{document} , \begin{document}$ {\rm{NO}}^{-}_{3}\text{-}{\rm{N}} $\end{document} ) but a negative correlation with soil microbial biomass carbon (MBC). Conclusion The expansion and eradication of moso bamboo resulted in the increase of soil greenhouse gas emission flux in Chinese fir forest, which had a negative impact on the regional atmospheric environment. On the other hand, the soil temperature and soil water content were the main driving factors for the three kinds of greenhouse gas emissions, and could lead to the differences in greenhouse gas emissions among the four stands. [Ch, 5 tab. 50 ref.]

Secular trends in diet-related greenhouse gas emission estimates since 2000 - a shift towards sustainable diets in Sweden.

This study examines secular changes in diet-related greenhouse gas emissions (GHGE) in younger and older Swedish adults, since the turn of this century. Two cross-sectional health examination surveys were conducted in 2001-2004 (T1) and 2014-2018 (T2). At both times, an eighty-six-item FFQ was embedded in the survey. From the food frequencies and age-standardised portion sizes, GHGE estimates (kg CO2e/year) were calculated. GHGE was modelled as a function of time period and covariates, for five distinct age groups. The municipality of Gothenburg, in western Sweden. Women and men aged 25-34, 35-44, 45-54, 55-64 and 65-75 years were randomly selected from the population registry and recruited for examinations. After exclusion of participants with incomplete dietary data, the analytic sample consisted of 2569 individuals at T1 and 2119 at T2. Lower dietary GHGE scores were observed at T2 compared with T1, in each age group, adjusting for sex, BMI and education. The largest differences in GHGE were observed in the youngest age group (approximately 30 % reduction). Decreasing trends in GHGE from animal-based foods were observed at all ages and were accompanied by smaller increases from plant-based sources in younger groups only. At all ages, GHGE from discretionary foods decreased, and prevalence of overweight remained stable. Optimal dietary trends should support both human health and planetary health. Our results suggest that Swedish adults have moved in this direction, e.g. through less intake of red meat products and stable weight status.

Responses of greenhouse gas emissions to different straw management methods with the same amount of carbon input in cotton field

Recycling crop straw to cropland can improve soil fertility, increase crop yield, and enhance soil carbon (C) sequestration, but also increase the risk of soil greenhouse gas (GHG) emissions. However, the differences in GHG emissions among different straw management methods are not well understood. Here, we investigated the responses of GHG emissions and their driving factors to the application of straw (S, 5.0 t ha−1), straw plus microbial inoculant (SI, 5.0 t ha−1), straw mulching (SM, 5.0 t ha−1), straw-biochar (SB, 3.5 t ha−1), and no straw or straw-biochar (CK) based on an equal amount of C input in a cotton field in Yancheng city, Jiangsu province, China from 2017 to 2018. Our results showed that the carbon dioxide (CO2) emissions from soil heterotrophic respiration were decreased markedly under SB, but increased markedly under SI and S. The response of soil methane (CH4) emissions to all treatments was similar to the CO2 emissions. Soil nitrous oxide (N2O) emissions were consistently decreased under SB, SI, S and SM, ranking as CK > SM > S>SI > SB. Compared with CK, SI and S significantly increased the global warming potential (GWP), whereas SB significantly decreased GWP by 17.9 %–19.8 %. Lint yield of cotton was highest in SB, followed by SI, S and SM, and lowest in CK. Consequently, SI, S and SM had no significant effects on the greenhouse gas intensity (GHGI), but SB significantly decreased GHGI by 28.4 %–35.7 %. In conclusion, straw-biochar application is an effective option for mitigating global warming and sustaining crop productivity.

How do water table drawdown, duration of drainage, and warming influence greenhouse gas emissions from drained peatlands of the Zoige Plateau?

AbstractAlpine peatlands on the Qinghai‐Tibet Plateau are an important soil carbon pool and are extremely sensitive to global change. Duration of drainage and water table drawdown accelerate peatland degradation because the soil changes from an anaerobic to aerobic environment, and climate warming exacerbates this shift. The objective of the present study was to evaluate the effects of drainage on microbial characteristics and greenhouse gas (GHG) emissions, as well as identify the factors mediating those effects. This study also analyzed whether warming increases the variability of GHG emissions. Watertable drawdown exerted greater influence on microbial communities than duration of drainage did. Watertable drawdown significantly increased the relative abundances of Proteobacteria, Acidobacteria, Actinobacteria, and Basidiomycota, and changes in soil microbiota correlated with differences in GHG emissions across three water‐table treatments. Longer drainage was associated with lower GHG emission; watertable drawdown decreased emissions of CO2 and CH4, but increased emission of N2O. In addition, high temperature increased CO2 emission by 75% and N2O emission by 42%, without significantly affecting CH4 emission. Structural equation modelling showed that microbes, especially prokaryotes (r = 0.79, p < 0.05 for all), were the primary factor affecting GHG emissions from drained peatlands. Overall, this study indicates that the watertable exerts a greater effect on GHG emissions than duration of drainage, and that warming increases variability of GHG emissions.

Understanding variability in greenhouse gas emission estimates of smallholder dairy farms in Indonesia

PurposeLife cycle assessment studies on smallholder farms in tropical regions generally use data that is collected at one moment in time, which could hamper assessment of the exact situation. We assessed seasonal differences in greenhouse gas emissions (GHGEs) from Indonesian dairy farms by means of longitudinal observations and evaluated the implications of number of farm visits on the variance of the estimated GHGE per kg milk (GHGEI) for a single farm, and the population mean.MethodsAn LCA study was done on 32 smallholder dairy farms in the Lembang district area, West Java, Indonesia. Farm visits (FVs) were performed every 2 months throughout 1 year: FV1–FV3 (rainy season) and FV4–FV6 (dry season). GHGEs were assessed for all processes up to the farm-gate, including upstream processes (production and transportation of feed, fertiliser, fuel and electricity) and on-farm processes (keeping animals, manure management and forage cultivation). We compared means of GHGE per unit of fat-and-protein-corrected milk (FPCM) produced in the rainy and the dry season. We evaluated the implication of number of farm visits on the variance of the estimated GHGEI, and on the variance of GHGE from different processes.Results and discussionGHGEI was higher in the rainy (1.32 kg CO2-eq kg−1 FPCM) than in the dry (0.91 kg CO2-eq kg−1 FPCM) season (P < 0.05). The between farm variance was 0.025 kg CO2-eq kg−1 FPCM in both seasons. The within farm variance in the estimate for the single farm mean decreased from 0.69 (1 visit) to 0.027 (26 visits) kg CO2-eq kg−1 FPCM (rainy season), and from 0.32 to 0.012 kg CO2-eq kg−1 FPCM (dry season). The within farm variance in the estimate for the population mean was 0.02 (rainy) and 0.01 (dry) kg CO2-eq kg−1 FPCM (1 visit), and decreased with an increase in farm visits. Forage cultivation was the main source of between farm variance, enteric fermentation the main source of within farm variance.ConclusionsThe estimated GHGEI was significantly higher in the rainy than in the dry season. The main contribution to variability in GHGEI is due to variation between observations from visits to the same farm. This source of variability can be reduced by increasing the number of visits per farm. Estimates for variation within and between farms enable a more informed decision about the data collection procedure.