scholarly journals CH4 and N2O Emissions From Cattle Excreta: A Review of Main Drivers and Mitigation Strategies in Grazing Systems

2021 ◽  
Vol 5 ◽  
Author(s):  
Julián Esteban Rivera ◽  
Julian Chará

Cattle production systems are an important source of greenhouse gases (GHG) emitted to the atmosphere. Animal manure and managed soils are the most important sources of emissions from livestock after enteric methane. It is estimated that the N2O and CH4 produced in grasslands and manure management systems can contribute up to 25% of the emissions generated at the farm level, and therefore it is important to identify strategies to reduce the fluxes of these gases, especially in grazing systems where mitigation strategies have received less attention. This review describes the main factors that affect the emission of GHG from manure in bovine systems and the main strategies for their mitigation with emphasis on grazing production systems. The emissions of N2O and CH4 are highly variable and depend on multiple factors, which makes it difficult to use strategies that mitigate both gases simultaneously. We found that strategies such as the optimization of the diet, the implementation of silvopastoral systems and other practices with the capacity to improve soil quality and cover, and the use of nitrogen fixing plants are among the practices with more potential to reduce emissions from manure and at the same time contribute to increase carbon capture and improve food production. These strategies can be implemented to reduce the emissions of both gases and, depending on the method used and the production system, the reductions can reach up to 50% of CH4 or N2O emissions from manure according to different studies. However, many research gaps should be addressed in order to obtain such reductions at a larger scale.

F1000Research ◽  
2021 ◽  
Vol 10 ◽  
pp. 1128
Author(s):  
Nam Tran Sy ◽  
Thao Huynh Van ◽  
Chiem Nguyen Huu ◽  
Cong Nguyen Van ◽  
Tarao Mitsunori

Background: Biochar is a promising material in mitigating greenhouse gases (GHGs) emissions from paddy fields due to its remarkable structural properties. Rice husk biochar (RhB) and melaleuca biochar (MB) are amendment materials that could be used to potentially reduce emissions in the Vietnamese Mekong Delta (VMD). However, their effects on CH4 and N2O emissions and soil under local water management and conventional rice cultivation have not been thoroughly investigated. Methods: We conducted a field experiment using biochar additions to the topsoil layer (0-20 cm). Five treatments comprising 0 t ha-1 (CT0); 5 t ha-1 (RhB5) and 10 t ha-1 (RhB10), and 5 t ha-1 (MB5) and 10 t ha-1 (MB10) were designed plot-by-plot (20 m2) in triplicates. Results: The results showed that biochar application from 5 to 10 t ha-1 significantly decreased cumulative CH4 (24.2 – 28.0%, RhB; 22.0 – 14.1%, MB) and N2O (25.6 – 41.0%, RhB; 38.4 – 56.4%, MB) fluxes without a reduction in grain yield. Increasing the biochar application rate further did not decrease significantly total CH4 and N2O fluxes but was seen to significantly reduce the global warming potential (GWP) and yield-scale GWP in the RhB treatments. Biochar application improved soil Eh but had no effects on soil pH. Whereas CH4 flux correlated negatively with soil Eh (P < 0.001; r2 = 0.552, RhB; P < 0.001; r2 = 0.502, MB). The soil physicochemical properties of bulk density, porosity, organic matter, and anaerobically mineralized N were significantly improved in biochar-amended treatments, while available P also slightly increased. Conclusions: Biochar supplementation significantly reduced CH4 and N2O fluxes and improved soil mineralization and physiochemical properties toward beneficial for rice plant. The results suggest that the optimal combination of biochar-application rates and effective water-irrigation techniques for soil types in the MD should be further studied in future works.


Author(s):  
Inderjot Chahal ◽  
Khagendra R. Baral ◽  
Kate A. Congreves ◽  
Laura L. Van Eerd ◽  
C. Wagner-Riddle

Horticultural systems, specifically vegetable production systems, are considered intensive agricultural systems as they are characterized by high nitrogen (N) fertilizer application rate, frequent tillage and irrigation operations. Accordingly, horticultural production in temperate climates is prone to N losses—mainly during post-harvest (during fall and winter) or pre-plant (spring) periods—such as N2O emissions and nitrate leaching. The risk for N losses is linked to low crop N use efficiency (NUE) combined with a narrow C:N and high N content of crop residues. Here we reviewed the studies conducted in Canada and similar climates to better understand the risk of N2O emission and potential agronomic management strategies to reduce N2O emissions from horticultural systems. Current knowledge on N2O emissions from horticultural systems indicate that increasing crop NUE, modifying the amount, type, time, and rate of N fertilizer inputs, and adopting cover crops in crop rotations are some of the effective approaches to decrease N2O emissions. However, there is uncertainty related to the efficiency of the existing N2O mitigation strategies due to the complex interactions between the factors (soil characteristics, type of plant species, climatic conditions, and soil microbial activity) responsible for N2O production from soil. Little research on N2O emissions from Canadian horticultural systems limits our ability to understand and manage the soil N2O production processes to mitigate the risk of N2O emissions. Thus, continuing to expand this line of research will help to advance the sustainability of Canadian horticultural cropping systems.


2008 ◽  
Vol 48 (2) ◽  
pp. 156 ◽  
Author(s):  
K. B. Kelly ◽  
F. A. Phillips ◽  
R. Baigent

Animal production systems in Australia are a significant contributor to nitrous oxide (N2O) emissions from soil, with the Australian Greenhouse Gas Inventory attributing ~25% of the N2O emissions from agricultural soils to animal production. Recent studies in New Zealand using dicyandiamide (DCD) in association with the application of urine to pastoral soil have reported reductions in N2O emission of up to 78% and reduced nitrate leaching of up to 45%. As such, the application of DCD to grazed pastures offers potential to reduce emissions resulting directly from animal production. This study was conducted on a border-check irrigated perennial pasture used for dairy production in northern Victoria. Automated enclosure chambers were linked to a fourier transformed infrared spectrometer to determine N2O emissions. The three treatments were a control, dairy cow urine (1000 kg N/ha) and dairy cow urine (1000 kg N/ha) with DCD included (10 kg/ha). The treatments were applied in mid-spring (15 September 2005) and again in mid-summer (25 January 2006) to a new area of pasture with N2O emissions measured for 120 and 70 days, respectively. Soil temperature and soil water content were monitored continuously. Soil inorganic-N was measured (0–100 mm) every 7 to 14 days for up to 120 days. Application of DCD reduced N2O emissions from a urine patch by 47% when applied in mid-spring and 27% when applied in mid-summer. The impact of the application of DCD on emissions from single urine patches lasted for ~50 days in mid-spring and 25 days in mid-summer. These reductions are lower than those reported in New Zealand studies and are likely to be related to soil conditions, principally temperature. The surface application of DCD has potential to reduce emissions from urine patches in northern Victoria; however, the effects are likely to be short-lived given the soil temperatures and high clay content typical of many Australian soils. More research is required to examine emission reduction options that are cost effective for animal production systems.


Author(s):  
Alexander N. Hristov

Agriculture is a significant source of methane, contributing about 12% of the global anthropogenic methane emissions. Major sources of methane from agricultural activities are fermentation in the reticulo-rumen of ruminant animals (i.e., enteric methane), fermentation in animal manure, and rice cultivation. Enteric methane is the largest agricultural source of methane and is mainly controlled by feed dry matter intake and composition of the animal diet (i.e., fiber, starch, lipids). Processes that lead to generation of methane from animal manure are similar to those taking place in the reticulo-rumen. Methane emissions from manure, however, are greatly influenced by factors such as manure management system and ambient temperature. Systems that handle manure as a liquid generate much more methane than systems in which manure is handled as a solid. Low ambient temperatures drastically decrease methane emissions from manure. Once applied to soil, animal manure does not generate significant amounts of methane. Globally, methane emissions from rice cultivation represent about 10% of the total agricultural greenhouse gas emissions. In the rice plant, methane dissolves in the soil water surrounding the roots, diffuses into the cell-wall water of the root cells, and is eventually released through the micropores in the leaves. Various strategies have been explored to mitigate agricultural methane emissions. Animal nutrition, including balancing dietary nutrients and replacement of fiber with starch or lipids; alternative sinks for hydrogen; manipulation of ruminal fermentation; and direct inhibition of methanogenesis have been shown to effectively decrease enteric methane emissions. Manure management solutions include solid-liquid separation, manure covers, flaring of generated methane, acidification and cooling of manure, and decreasing manure storage time before soil application. There are also effective mitigation strategies for rice that can be categorized broadly into selection of rice cultivars, water regime, and fertilization. Alternate wetting and drying and mid-season drainage of rice paddies have been shown to be very effective practices for mitigating methane emissions from rice production.


2015 ◽  
Vol 8 ◽  
pp. 623
Author(s):  
Patrícia Perondi Anchão Oliveira

O aquecimento global, acentuado por ações antrópicas de emissão de gases de efeito estufa, tem como consequência as mudanças climáticas, que causam muitos transtornos ambientais para a humanidade. A atividade pecuária produz gases de efeito estufa na forma de metano (CH4) e óxido nitroso (N2O) principalmente, com tendência de aumento de emissão atrelado ao aumento da produção pecuária. A degradação de pastagens, o mais importante problema ambiental da pecuária, também pode contribuir para a emissão desses gases e pode levar à desertificação. Ações de mitigação dessas emissões podem amenizar o problema e devem ser observadas considerando-se o balanço de carbono dos sistemas de produção pecuários, onde, além da emissão de gases de efeito estufa, o sequestro de carbono é também considerado. Na pecuária, existe possibilidade de mitigação das emissões pela redução da emissão do CH4 e do N2O, entretanto, o maior potencial de mitigação das emissões está no sequestro de carbono devido à recuperação das pastagens. Apesar disso, grande ênfase é dada aos aspectos envolvendo a emissão de CH4 entérico pelos ruminantes e suas formas de mitigação. Também é importante ressaltar que a adoção das tecnologias que promovem a mitigação das emissões de gases de efeito estufa depende mais de questões econômicas do que da viabilidade técnica das ações de mitigação propostas. Global warming is intensified by greenhouse gases emissions from human activities, resulting in climate change and causing many environmental disorders for humanity. The livestock produces greenhouse gases such as methane (CH4) and nitrous oxide (N2O) mainly and the increasing in emissions is linked to increased livestock production. The degradation of pastures had been the most important issue of livestock contributing to the greenhouse gases emissions and leading the desertification. Mitigation actions can reduce these emissions and the carbon balance of livestock production systems, which also considerate carbon sequestration besides the emission of greenhouse gases. Mitigating emissions of CH4 and N2O are possible in livestock but the carbon sequestration that occurs during the recovery of pasture is the greatest potential for mitigating greenhouse. Nevertheless, great emphasis can be found in literature related to the aspects involving the issue of enteric methane by ruminants and its methods of mitigation. Importantly, the adoption of technologies that promote mitigation of greenhouse gases emissions is most dependent of economic issues than technical feasibility of the mitigation actions proposed. Keywords: livestock, desertification, degradation, methane, nitrous oxide.   


2020 ◽  
Vol 60 (1) ◽  
pp. 55 ◽  
Author(s):  
B. Horan ◽  
J. R. Roche

The sustainable intensification of pasture-based food-production systems provides an opportunity to align the ever-increasing global demand for food with the necessity for environmentally efficient ruminant production. Biophysically and financially resilient grazing systems are designed to harvest a large amount of the pasture grown directly by the cow, while minimising the requirement for machinery and housing, and exposure to feed prices. This is primarily achieved by matching the feed demand of the herd with the annual pasture supply profile (i.e. seasonal milk production). Ideally, the entire herd is calved before pasture growth equals herd demand; breeding and drying-off policies facilitate this. The type of cow is also important; she must be highly fertile and have good grazing-behaviour characteristics. Pasture species are chosen to best suit the predominant climate, and pasture management aims to maximise the production and utilisation of chosen species. Purchased supplementary feeds support biophysical resilience and can be successfully incorporated into grazing systems, if stocking rate (SR) is increased to achieve high pasture utilisation. However, industry databases indicate that, on average, profitability declines with increasing purchased supplementary-feed usage, because of reduced pasture utilisation and lower than expected marginal milk-production responses. In the present paper, we outline the characteristics of resilient pasture-based dairy systems in the context of the necessity for the sustainable intensification of global food production.


2016 ◽  
Vol 56 (9) ◽  
pp. 1376 ◽  
Author(s):  
E. J. McGahan ◽  
F. A. Phillips ◽  
S. G. Wiedemann ◽  
T. A. Naylor ◽  
B. Warren ◽  
...  

In the Australian pork industry, manure is the main source of greenhouse gases (GHG). In conventional production systems, effluent from sheds is transferred into open anaerobic ponds where the effluent is typically stored for many months, with the potential of generating large quantities of GHG. The present study measured methane (CH4), nitrous oxide (N2O) and ammonia (NH3) emissions from a conventional anaerobic effluent pond (control), a short hydraulic retention-time tank (short HRT, mitigation) and from the animal housing for a flushing piggery in south-eastern Queensland, over two 30-day trials during summer and winter. Emissions were compared to determine the potential for a short HRT to reduce emissions. Average CH4 emissions from the pond were 452 ± 37 g per animal unit (AU; 1 AU = 500 kg liveweight) per day, during the winter trial and 789 ± 29 g/AU.day during the summer trial. Average NH3 emissions were 73 ± 8 g/AU.day during the winter trial and 313 ± 18 g/AU.day during the summer trial. High emission factors during summer will be temperature driven and influenced by the residual volatile solids and nitrogen (N) deposited in the pond during winter. Average NH3 emissions from the piggery shed were 0.707 ± 0.050 g/AU.day and CH4 emissions were 0.344 ± 0.116 g/AU.day. The N2O concentrations from both the pond and shed were close to, or below, the detection limits. Total emissions from the short HRT during the winter and summer trials, respectively, were as follows: CH4 10.65 ± 0.616 mg/AU.day and 4108 ± 473 mg/AU.day; NH3-N 1.15 ± 0.07 mg/AU.day and 29.8 ± 2.57 mg/AU.day; N2O-N 0.001 ± 0.00052 mg/AU.day and 5.9 ± 0.321 mg/AU.day. On the basis of a conservative analysis of CH4 emissions relative to the inflow of volatile solids, and NH3 and N2O emissions as a fraction of the excreted N, GHG emissions were found to be 79% lower from the short-HRT system. This system provides a potential mitigation option to reduce GHG emissions from conventional pork production in Australia.


2016 ◽  
Vol 1 (2) ◽  
pp. 111
Author(s):  
Ali Pramono

On the integration of crop-livestock systems, waste biomass is used as feed for livestock. Low feed quality may increase emissions of greenhouse gases (GHG). Therefore, to reduce emissions from livestock sector is to improve the quality of animal feed. The purpose of this study was to obtain additional information about the effect of feeding (silage, hay ammoniation and UMMB) against greenhouse gas emissions from cattle manure in crop-livestock integration system. The experiment was conducted at the experimental field of Indonesia Agricultural Environment Research Institute (IAERI/Balingtan), Pati in May-July 2014. The method used to measure the GHG emissions is close chamber method, with an interval of 10 minutes. Samples of CO2, CH4 and N2O were analyzed using gas chromatography. The results showed that treatment of conventional feeding + feed supplement could reduce GHG emissions as 19 % compared to a conventional feeding. GHG emissions from animal manure fed conventional feed of 9.13 kg/head/year, whereas with conventional feed + additional feed of 7.39 kg/head/year.


2021 ◽  
Author(s):  
Alejandra Ortega ◽  
Mark Tester ◽  
Kyle Lauersen

Abstract Livestock contributes to 14.5 percent of global greenhouse gas emissions, with ruminants being the largest contributor through enteric methane emissions. Although several strategies are available to mitigate livestock methane, no consensus exists on which methods are the most effective. Here, we projected by 2050 the impact of the most pragmatic strategies to reduce enteric methane, modelling cattle emissions. The projection shows that supplementing ruminant feed with anti-methanogenic seaweed and converting grassland into silvopasture offer the greatest potential to reduce emissions. A synergic combination of strategies can aid Europe and most of Asia to can reach ruminant carbon neutrality by 2035 and 2038, respectively. However, global cattle CO2-eq emissions will be reduced by no more than 34 percent by 2050, remaining far above the carbon neutrality target. Mitigation strategies alone are insufficient to lower emissions, and reducing the demand for ruminant products is also necessary – particularly in Africa and Western Asia.


2014 ◽  
Vol 54 (9) ◽  
pp. 1141 ◽  
Author(s):  
David Pacheco ◽  
Garry Waghorn ◽  
Peter H. Janssen

Ruminants contribute to human food supply and also anthropogenic greenhouse gas (GHG) emissions. An understanding of production systems and information on animal populations has enabled global inventories of ruminant GHG emissions (methane and nitrous oxide), and dietary strategies are being developed to reduce GHG emissions from ruminants. Mitigation strategies need to consider the management/feeding systems used to ensure that these strategies will be readily accepted and adopted by farmers. Housed systems allow diets to be formulated in ways that may reduce GHG production, but the challenge is much greater for systems where animals graze outdoors for long periods. A methane mitigation option in the form of fresh forage would be desirable in livestock production systems with high reliance on grazing. A brief summary of New Zealand research, carried out on fresh grasses, legumes, herbs and crops, suggest that we have an incomplete understanding of the feed characteristics that define a ‘high’ or a ‘low’ methane feed. The variation in methane emissions measured between feeds, individual animals and experiment is large, even in controlled conditions, and the dynamic nature of sward-animal interactions will only exacerbate this variation, creating challenges beyond the identification of mitigants. Furthermore, implementation of knowledge gained from controlled studies requires validation under grazing systems to identify any trade-offs between methane reduction and animal productivity or emission of other pollutants. Therefore, investment and research should be targeted at mitigation options that can and will be adopted on-farm, and the characteristics of temperate grasslands farming suggest that these options may differ from those for intensive (high input/output) or extensive (low input/output) systems.


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