scholarly journals Calculation of new enteric methane emission factors for small ruminants in western Kenya highlights the heterogeneity of smallholder production systems

2021 ◽  
Vol 61 (6) ◽  
pp. 602
Author(s):  
J. P. Goopy ◽  
P. W. Ndung'u ◽  
A. Onyango ◽  
P. Kirui ◽  
K. Butterbach-Bahl

Context African livestock play a critical role in food security and the wider economy, while accounting for >70% of African agricultural greenhouse gas emissions. Accurate estimates of greenhouse gas emissions from livestock are required for inventory purposes and to assess the efficacy of mitigation measures. While there is an increasing number of studies assessing methane (CH4) emissions of cattle, little attention has been paid to small ruminants (SR). Aims Enteric CH4 emissions were assessed from 1345 SR in three counties of western Kenya to develop more accurate emission factors (EF) for enteric CH4 from sheep and goats. Methods Using on-farm animal activity data, feed samples were also analysed to produce estimates of feed digestibility by season and region. The combined data were also used to estimate daily CH4 production by season, location and class of animal to produce new EF for annual enteric CH4 production of SR. Key results Mean dry-matter digestibility of the feed basket was in the range of 58–64%, depending on region and season (~10% greater than Tier I estimates). EF were similar for sheep (4.4 vs 5 kg CH4/year), but lower for goats (3.7 vs 5 kg CH4/year) than those given for SR in developing countries in Intergovernmental Panel on Climate Change (Tier I) estimates. Conclusions Published estimates of EF for SR range widely across Africa. In smallholder systems in western Kenya, SR appear to be managed differently from cattle, and EF appear to be driven by different management considerations. Implications The findings highlighted the heterogenous nature of SR enteric emissions in East Africa, but also suggested that emissions from SR are quantitatively less important than other estimates suggest compared with cattle.

2019 ◽  
Vol 3 (4) ◽  
pp. 1383-1388 ◽  
Author(s):  
Breanna M Roque ◽  
Henk J Van Lingen ◽  
Hilde Vrancken ◽  
Ermias Kebreab

Abstract: Enteric methane (CH4) production is the main source of greenhouse gas emissions from livestock globally with beef cattle contributing 5.95% of total global greenhouse gas emissions. Various mitigation strategies have been developed to reduce enteric emissions with limited success. In vitro studies have shown a reduction in CH4 emissions when using garlic and citrus extracts. However, there is paucity of data regarding in vivo studies investigating the effect of garlic and citrus extracts in cattle. The objective of this study was to quantitatively evaluate the response of Angus × Hereford cross steers consuming the feed additive Mootral, which contains extracts of both garlic and citrus, on CH4 yield (g/kg dry matter intake [DMI]). Twenty steers were randomly assigned to two treatments: control (no additive) and Mootral supplied at 15 g/d in a completely randomized design with a 2-wk covariate and a 12-wk data collection periods. Enteric CH4 emissions were measured using the GreenFeed system during the covariate period and experimental weeks 2, 6, 9, and 12. CH4 yield (g/kg DMI) by steers remained similar in both treatments for weeks 2 to 9. In week 12, there was a significant decrease in CH4 yield (23.2%) in treatment compared to control steers mainly because the steers were consuming all the pellets containing the additive. However, overall CH4 yield (g/kg DMI) during the entire experimental period was not significantly different. Carbon dioxide yield (g/kg DMI) and oxygen consumption (g/kg DMI) did not differ between treatments during the entire experimental period. DMI, average daily gain, and feed efficiency also remained similar in control and supplemented steers. The in vivo results showed that Mootral may have a potential to be used as a feed additive to reduce enteric CH4 production and yield in beef cattle but needs further investigation under various dietary regimen.


2016 ◽  
Vol 56 (9) ◽  
pp. 1432 ◽  
Author(s):  
J. Biala ◽  
N. Lovrick ◽  
D. Rowlings ◽  
P. Grace

Emissions from stockpiled pond sludge and yard scrapings were compared with composted dairy-manure residues blended with shredded vegetation residues and chicken litter over a 5-month period at a farm in Victoria (Australia). Results showed that methane emissions occurred primarily during the first 30–60 days of stockpiling and composting, with daily emission rates being highest for stockpiled pond sludge. Cumulated methane (CH4) emissions per tonne wet feedstock were highest for stockpiling of pond sludge (969 g CH4/t), followed by composting (682 g CH4/t) and stockpiling of yard scrapings (120 g CH4/t). Sizeable nitrous oxide (N2O) fluxes were observed only when temperatures inside the compost windrow fell below ~45−50°C. Cumulated N2O emissions were highest for composting (159 g N2O/t), followed by stockpiling of pond sludge (103 g N2O/t) and yard scrapings (45 g N2O/t). Adding chicken litter and lime to dairy-manure residues resulted in a very low carbon-to-nitrogen ratio (13 : 1) of the composting mix, and would have brought about significant N2O losses during composting. These field observations suggested that decisions at composting operations, as in many other businesses, are driven more by practical and economic considerations rather than efforts to minimise greenhouse-gas emissions. Total greenhouse-gas emissions (CH4 + N2O), expressed as CO2-e per tonne wet feedstock, were highest for composting (64.4 kg), followed by those for stockpiling of pond sludge (54.5 kg) and yard scraping (16.3 kg). This meant that emissions for composting and stockpiling of pond sludge exceeded the new Australian default emission factors for ‘waste composting’ (49 kg). This paper proposes to express greenhouse-gas emissions from secondary manure-management systems (e.g. composting) also as emissions per tonne wet feedstock, so as to align them with the approach taken for ‘waste composting’ and to facilitate the development of emission-reduction methodologies for improved manure management at the farm level.


2018 ◽  
Vol 5 (1) ◽  
pp. 9-14 ◽  
Author(s):  
Amir Zahedi ◽  
Sorour Ghodrati ◽  
Mehdi Ahmadimoghaddam ◽  
Nematollah Jaafarzadeh

2021 ◽  
pp. 089033442199476
Author(s):  
JP Dadhich ◽  
Julie P. Smith ◽  
Alessandro Iellamo ◽  
Adlina Suleiman

Background There is growing recognition that current food systems and policies are environmentally unsustainable. There is an identified need to integrate sustainability objectives into national food policy and dietary recommendations. Research Aims To (1) describe exploratory estimates of greenhouse gas emission factors for all infant and young child milk formula products and (2) estimate national greenhouse gas emission association with commercial milk formulas sold in selected countries in the Asia Pacific region. Method We used a secondary data analysis descriptive design incorporating a Life Cycle Assessment (LCA) concepts and methodology to estimate kg CO2 eq. emissions per kg of milk formula, using greenhouse gas emission factors for milk powder, vegetable oils, and sugars identified from a literature review. Proportions of ingredients were calculated using FAO Codex Alimentarius guidance on milk formula products. Estimates were calculated for production and processing of individual ingredients from cradle to factory gate. Annual retail sales data for 2012–2017 was sourced from Euromonitor International for six purposively selected countries; Australia, South Korea, China, Malaysia, India, Philippines. Results Annual emissions for milk formula products ranged from 3.95–4.04 kg CO2 eq. Milk formula sold in the six countries in 2012 contributed 2,893,030 tons CO2 eq. to global greenhouse gas emissions. Aggregate emissions were highest for products (e.g., toddler formula), which dominated sales growth. Projected 2017 emissions for milk formula retailed in China alone were 4,219,052 tons CO2 eq. Conclusions Policies, programs and investments to shift infant and young child diets towards less manufactured milk formula and more breastfeeding are “Triple Duty Actions” that help improve dietary quality and population health and improve the sustainability of the global food system.


2016 ◽  
Author(s):  
Matthew J. Bridgman ◽  
Barry H. Lomax ◽  
Sofie Sjogersten

Abstract. Wetland vegetation provide strong controls on greenhouse gas fluxes but impacts of elevated atmospheric carbon dioxide (CO2) levels on greenhouse gas emissions from wetlands are poorly understood. This study aims to investigate if elevated atmospheric CO2 enhance methane (CH4) emissions from subarctic wetlands and to determine if responses are comparable or species specific within the Cyperaceae, an important group of artic wetland plants. To achieve this we carried out a combined field and laboratory investigation to measure of CO2 and CH4 fluxes. The wetland was a CH4 source with comparable fluxes from areas with and without vegetation and across the different sedge communities. In contrast, the net ecosystem exchange of CO2 differed with sedge species. Within the laboratory experiment plants grown at double ambient (800 ppm) CO2, total biomass of Eriophorum vaginatum and Carex brunnescens increased, whereas the total biomass of E. angustifolium and C. acuta decreased, compared to the control (400 ppm CO2). These changes in biomass were associated with corresponding changes in CH4 flux. E. vaginatum and C. brunnescens mesocosms produced more CH4 when grown in 800 ppm atmospheric CO2 when compared to 400 ppm CO2 with E. angustifolium and C. acuta producing less. Additionally, redox potential and carbon substrate availability in the pore water differed among the plant treatments and in response to the elevated CO2 treatment. Together, this suggests species specific controls of CH4 emissions in response to elevated CO2, which facilitate differential plant growth responses and modification of the rhizosphere environments. Our study highlights species composition as an important control of greenhouse gas feedbacks in a CO2 rich future, which need to be considered in models aiming to predict how ecosystems respond to climate change.


2021 ◽  
Author(s):  
Sascha M.B. Krause ◽  
Stefan Bertilsson ◽  
Hans-Peter Grossart ◽  
Paul L.E. Bodelier ◽  
Peter van Bodegom ◽  
...  

Conventional agricultural practices negatively impact soil biodiversity, carbon stocks, and greenhouse gas emissions in ways that make them unsustainable for supporting future supply of food and fiber. Better management of agrobiodiversity will likely play a critical role in transitioning towards more sustainable practices. In particular, innovation and developments targeting the aboveground and belowground components of agroecosystems should be informed by frameworks and approaches that harness the –in particular functional– diversity of complex microbial communities. Here, we review and discuss microbial trait-based approaches that will help us understand and steer agroecosystem functioning in the face of global change. We highlight how trait-based approaches can improve agricultural practices related to soil functioning (e.g. soil fertility and aggregation); climate regulation (e.g. carbon storage and greenhouse gas emissions) and adaptation to climate change; plant health; and reduction of contaminant-related hazards for human health. We also consider how microbial trait-based approaches can be used as a tool to improve cultivated plant performance through artificial selection and microbiome engineering. Last, we discuss the inherent obstacles associated with the development and implementation of trait-based approaches owing to strong interactions within microbial communities and linkages between plants and the soil environment. Despite these obstacles, microbial trait-based approaches hold promise for the sustainable management of agricultural ecosystems needed to feed and nourish a rapidly growing human population.


2018 ◽  
Vol 58 (6) ◽  
pp. 1087 ◽  
Author(s):  
G. N. Ward ◽  
K. B. Kelly ◽  
J. W. Hollier

Nitrous oxide (N2O) from excreta deposited by grazing ruminants is a major source of greenhouse gas emissions in Australia. Experiments to measure N2O emissions from dairy cow dung, urine and pond sludge applied to pasture, and the effectiveness of the nitrification inhibitor nitrapyrin in reducing these emissions, were conducted in south-western Victoria, Australia. In Experiment 1, emissions from urine, with and without nitrapyrin, and from dung were measured. Treatments applied in September 2013 resulted in cumulative emissions (245 days) of 0.60, 5.35, 4.15 and 1.02 kg N2O-nitrogen (N)/ha for the nil, urine (1000 kg N/ha), urine (1000 kg N/ha) + nitrapyrin (1 kg active ingredients/ha), and dung (448 kg N/ha) treatments, respectively, giving emission factors of 0.47% and 0.09% for urine and dung respectively. Nitrapyrin reduced N2O emissions from urine for 35 days, with an overall reduction in emissions of 25%. In Experiment 2, sludge, with and without nitrapyrin, was applied in May 2014, and dung was applied in May, August, November 2014 and January 2015. Cumulative emissions (350 days) were 0.19, 0.49, 0.31 and 0.39 kg N2O-N/ha for the nil, sludge (308 kg N/ha), sludge (308 kg N/ha) + nitrapyrin (1 kg active ingredients/ha), and dung (total 604 kg N/ha) treatments, respectively, giving emission factors of 0.10% and 0.03% for sludge and dung. Nitrapyrin reduced N2O emissions from sludge for 60 days, with an overall reduction in emissions of 59%. A third experiment on two soil types compared emissions from urine and dung, with and without nitrapyrin, applied in different seasons of the year. Emissions were highly seasonal and strongly related to soil water status. Emission factors (90 days) ranged from 0.02% to 0.19% for urine and 0.01% to 0.12% for dung. Nitrapyrin reduced emissions from urine by 0–35% and had little effect on emissions from dung. Overall, the experiments found that nitrapyrin was an effective tool in reducing emissions from urine, dung and sludge applied to pasture, but the magnitude varied across the year, with nitrapyrin being most effective when soils had >70% water-filled pore space when major emissions occurred.


2021 ◽  
Vol 20 (4) ◽  
pp. 223-233
Author(s):  
Jonathan Gervaix ◽  
Pascal Breil ◽  
Franck Poly ◽  
Philippe Namour

Description and validation of a new simple, inexpensive iso-pressure device for quantitative measurements of gas emissions in river (the SNIFFER for "Sampler of Natural InFluxes of Foul Emissions from River sediment"). The Sniffer was validated, during two field campaigns, a first in winter (18/12/13 to 20/02/14) and a second in spring (16/04/14 to 14/05/14) on a stream receiving some organic matter from a combined sewer overflow. The measured CH4 emissions are of the order of 0.50 L/(m2.day). This production is far from negligible and commits us to reconsider the contribution of water systems in total greenhouse gas emissions.


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