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1.
Ciênc. rural (Online) ; 53(5): 1-10, 2023. ilus, tab
Artigo em Inglês | VETINDEX | ID: biblio-1412853

Resumo

Most energy used to operate agricultural machines in the field is generated from fossil fuel combustion. The combustion process emits atmospheric pollutants, increasing the emission of greenhouse gases (GHGs). In this context, this review is to discuss technologies for mitigating diesel engine GHG emissions to advance sustainable development in the agricultural machinery sector. This paper presents strategies and technologies widely adopted by agricultural machinery manufacturers in controlling pollutant emissions during fuel combustion. The findings of this study encompass sustainable alternative technologies, such as selective catalytic reduction, exhaust gas recirculation, diesel particulate filter, and fuels. This study helps reveal the environmental impact of agricultural field operations that generate GHG emissions.


Grande parte da energia utilizada para o funcionamento das máquinas agrícolas em suas operações no campo ainda é resultante da combustão de combustíveis fósseis. O processo de combustão provoca a emissão de poluentes atmosféricos que contribuem para o aumento dos Gases de Efeito Estufa (GEE). Neste contexto, esta revisão tem como objetivo descrever as tecnologias que contribuem para mitigar as emissões de GEE pelos motores de ciclo Diesel, a fim de contribuir para a compreensão e o desenvolvimento da sustentabilidade no setor de máquinas agrícolas. São apresentadas as estratégias e tecnologias que comumente estão sendo adotadas pelos fabricantes de máquinas agrícolas para o controle das emissões de poluentes, durante o processo de combustão do combustível. Os achados do estudo apresentam as alternativas tecnológicas sustentáveis como a Selective Catalytic Reduction, Exhaust Gas Recirculation, Diesel Particulate Filter, e sobre o uso de combustíveis alternativos. Ainda, contribui para o entendimento do impacto ambiental das operações agrícolas em campo, que provocam as emissões de GEE.


Assuntos
Automação , Combustíveis , Vazamento de Gases , Maquinaria , Gases de Efeito Estufa
2.
J. Anim. Behav. Biometeorol ; 10(02): 2210, Apr. 2022. tab, graf
Artigo em Inglês | VETINDEX | ID: biblio-1399410

Resumo

The objective of this study was to evaluate in vitro rumen fermentation and methane production under the influence of two sources of phytochemicals: essential oils (EOs) and aqueous extracts (AEs). Treatments were set up in a completely randomized block design, with 4×2+1 factorial arrangement of four species, S (garlic, G; cinnamon, C; rosemary, R; eucalyptus; EU) × two types of presentation, P (essential oil, EO; aqueous extract, AE) and a basal diet, BD (50% concentrate, 20% alfalfa and 30% corn silage). Rumen fermentation was evaluated using the in vitro gas production technique. All experimental units were incubated with 500 mg of BD for 72 hours. Treatments were added at a single dose of 900 mg/L of rumen inoculum. Gas pressure was recorded at 0, 2, 4, 6, 8, 10, 14, 18, 24, 30, 36, 42, 48, 60 and 72 h postincubation. There was an interaction effect (P × S) between plant extract presentation (P) and plant species (S) for all variables. Treatments GEO, CEO, REO decreased volatile fatty acids (mmol/200 mg), microbial mass production (mg/g), CH4 production (mL/g), in vitro dry matter digestibility (P < 0.05), and total gas production at 24 and 72 h post-incubation (P < 0.05; mL/g DM, mL/g OM). No differences (P > 0.05) were observed between AEs and BD. In conclusion, the use of EOs negatively affected rumen fermentation parameters and the production of CH4. Garlic and cinnamon EOs effectively reduced methane emissions; however, they also reduced in vitro dry matter digestibility.


Assuntos
Animais , Ovinos/metabolismo , Cinnamomum zeylanicum/química , Gases de Efeito Estufa/análise , Ruminação Digestiva/fisiologia , Alho/química , Metano/análise , Óleos Voláteis , Compostos Fitoquímicos/administração & dosagem
3.
Sci. agric ; 78(1): e20180355, 2021. map, tab, graf
Artigo em Inglês | VETINDEX | ID: biblio-1497915

Resumo

Forest soils are N2O sources and commonly act as CH4 sinks. This study evaluated the dynamics of the CH4 and N2O fluxes of soils under Eucalyptus plantations and native Cerrado vegetation, as well as possible interactions between environmental factors and fluxes. The study was carried out in the Distrito Federal, Brazil, during 26 months, in three areas: in two stands of the hybrid Eucalyptus urophylla × Eucalyptus grandis, planted in 2011 (E1), and in 2009 (E2) and native Cerrado vegetation (CE). Measurements to determine the fluxes in a closed static chamber were carried out from Oct 2013 to Nov 2015. Soil and climate factors were monitored. During the study period, the mean CH4 fluxes were –22.48, –8.38 and –1.31 μg CH4 m–2 h–1 and the mean N2O fluxes 5.45, 4.85 and 3.85 μg N2O m–2 h–1 from E1, E2 and CE, respectively. Seasonality affected plantations in the studied sites. Cumulative CH4 influxes were calculated (year-1: –1.86 to -0.63 kg ha–1 yr–1; year-2: –1.85 to –1.34 kg ha–1 yr–1). Cumulative N2O fluxes in the three sites were ≤ 0.85 kg ha–1 yr–1. The change in land use from Cerrado to Eucalyptus plantations did not significantly changed regarding greenhouse gases (GHG), compared to the native vegetation. Flux rates of both gases (N2O and CH4) were low. Temporal variations in GHG fluxes and different ages of the stands did not cause significant differences in cumulative annual fluxes.


Assuntos
Eucalyptus/química , Gases de Efeito Estufa , Metano , Árvores/química , Óxido Nitroso , Brasil
4.
Rev. bras. zootec ; 50: e20200185, 2021. ilus, mapas, tab, graf
Artigo em Inglês | VETINDEX | ID: biblio-1443290

Resumo

Based on previous reports, our study aimed to obtain the first estimate on the contribution of termite mounds to CH4 emissions in Brazilian Cerrado pastures. We estimated that termite mounds occupy an area larger than 200,000 ha in degraded pastures, an important loss of grazing area considering the current scenario of land-use change of pastures to other crops in Brazil. Moreover, mound-building termites in degraded pastures may be responsible for CH4 emissions greater than 11 Mt CO2 eq. yr−1, which would notably affect the greenhouse gases (GHG) balance of grass-fed cattle production in Brazil. In this sense, it is urgent to conduct field-scale studies about the CH4 emissions by mound-building termites in pastures and its contribution to the C footprint of Brazilian beef.


Assuntos
Pastagens , Isópteros/química , Gases de Efeito Estufa/análise , Metano/análise , Brasil
5.
Sci. agric. ; 78(1): e20180355, 2021. mapas, tab, graf
Artigo em Inglês | VETINDEX | ID: vti-27644

Resumo

Forest soils are N2O sources and commonly act as CH4 sinks. This study evaluated the dynamics of the CH4 and N2O fluxes of soils under Eucalyptus plantations and native Cerrado vegetation, as well as possible interactions between environmental factors and fluxes. The study was carried out in the Distrito Federal, Brazil, during 26 months, in three areas: in two stands of the hybrid Eucalyptus urophylla × Eucalyptus grandis, planted in 2011 (E1), and in 2009 (E2) and native Cerrado vegetation (CE). Measurements to determine the fluxes in a closed static chamber were carried out from Oct 2013 to Nov 2015. Soil and climate factors were monitored. During the study period, the mean CH4 fluxes were –22.48, –8.38 and –1.31 μg CH4 m–2 h–1 and the mean N2O fluxes 5.45, 4.85 and 3.85 μg N2O m–2 h–1 from E1, E2 and CE, respectively. Seasonality affected plantations in the studied sites. Cumulative CH4 influxes were calculated (year-1: –1.86 to -0.63 kg ha–1 yr–1; year-2: –1.85 to –1.34 kg ha–1 yr–1). Cumulative N2O fluxes in the three sites were ≤ 0.85 kg ha–1 yr–1. The change in land use from Cerrado to Eucalyptus plantations did not significantly changed regarding greenhouse gases (GHG), compared to the native vegetation. Flux rates of both gases (N2O and CH4) were low. Temporal variations in GHG fluxes and different ages of the stands did not cause significant differences in cumulative annual fluxes.(AU)


Assuntos
Eucalyptus/química , Metano , Óxido Nitroso , Gases de Efeito Estufa , Árvores/química , Brasil
6.
Rev. bras. zootec ; 49: e20200017, 2020. ilus, tab, graf
Artigo em Inglês | VETINDEX | ID: biblio-1443602

Resumo

The objective of this study was to evaluate natamycin, Lactobacillus buchneri (LB), or their combination on the chemical composition, loss, fermentative profile, and aerobic stability as well as gas production and composition of sugarcane silages. The treatments were (wet basis): no additive (control), 10 g t−1 of natamycin (N10), 5 × 104 cfu g−1 of LB, and the combination of 4 g t−1 of natamycin and 2.5 × 104 cfu g−1 of LB (NLB). Sugarcane was chopped (10 mm), treated with the additives, and ensiled in experimental silos (four replicates). The silos remained stored for 51 days. The LB inoculation, alone or in combination with natamycin, increased the acetic acid content (by 105 and 78% respectively) and decreased ethanol content (by 83 and 71% respectively) when compared to N10 treatment and the control. A decrease in both dry matter and gas losses was observed in the LB (by 72 and 78%, respectively) and N10 (by 69 and 77%, respectively) silages compared with the control, but not the combination. The N10 treatment reduced greenhouse gas (GHG) emission by 86% compared with the control silage. Control and N10 silages deteriorated to the same extent with aerobic exposure, whereas LB and NLB presented higher aerobic stability. The use of natamycin alone is not recommended when ethanol and aerobic stability are concerns. However, natamycin may be considered for the composition of blend additives to decrease greenhouse gas emission and fermentative loss in silages. Further studies must be carried out to optimize doses of natamycin in blend additives.(AU)


Assuntos
Silagem/análise , Natamicina/efeitos adversos , Gases de Efeito Estufa/análise , Excipientes Farmacêuticos/análise , Saccharum/química
7.
J. Anim. Behav. Biometeorol. ; 6(4): 109-115, Oct.2018. graf, tab
Artigo em Inglês | VETINDEX | ID: vti-736247

Resumo

The objectives of this study were to examine the trends of greenhouse gas (GHG) emission intensity (EI) from livestock sector in Indonesia, and also to suggest mitigation measures for the emissions. GHG emissions were calculated by using 2006 Intergovernmental Panel on Climate Change Guideline (2006 IPCC GL) Tier 1 method based on carbon dioxide equivalent (CO2eq) with default values except for Indonesian livestock population. GHG EI (emissions intensity) of livestock sector in Indonesia was calculated by dividing total GHG emissions by Indonesian meat production from livestock commodities. In 2015, beef cattle contributed 66.99% from total GHG emissions from livestock sector, followed by goat (8.38%), sheep (7.40%), buffalo (6.89%), swine (5.03%), broiler chicken (3.80%), and horse (0.72%). However, in 2015, buffalo showed the highest EI (kgCO2eq/kg meat) by 6.44, followed by beef cattle (5.88), sheep (4.69), goat (4.07), swine (3.50), horse (3.09), and broiler chicken (0.38). EIs from swine, goat, sheep, broiler chicken, horse, beef cattle, and buffalo decreased by 60.77%, 58.59%, 46.68%, 21.30%, 18.15%, 19.94%, and 13.13% from 2000 to 2015, respectively. Results of GHG emissions and GHG EIs from each livestock category in Indonesia shown the improvement direction in order to mitigate GHG emission. Therefore, Indonesian government should focus on the beef cattle and buffalo that are a high contribution on GHG emissions and high EI by increasing the efficiency of livestock rearing management such as livestock health, genetic, diets, and environment.(AU)


Assuntos
Criação de Animais Domésticos , Gases de Efeito Estufa/análise , Gases de Efeito Estufa/prevenção & controle , Indústria Agropecuária , Indonésia , Mudança Climática , 34691
8.
J. Anim. Behav. Biometeorol ; 6(4): 109-115, Oct.2018. graf, tab
Artigo em Inglês | VETINDEX | ID: biblio-1484252

Resumo

The objectives of this study were to examine the trends of greenhouse gas (GHG) emission intensity (EI) from livestock sector in Indonesia, and also to suggest mitigation measures for the emissions. GHG emissions were calculated by using 2006 Intergovernmental Panel on Climate Change Guideline (2006 IPCC GL) Tier 1 method based on carbon dioxide equivalent (CO2eq) with default values except for Indonesian livestock population. GHG EI (emissions intensity) of livestock sector in Indonesia was calculated by dividing total GHG emissions by Indonesian meat production from livestock commodities. In 2015, beef cattle contributed 66.99% from total GHG emissions from livestock sector, followed by goat (8.38%), sheep (7.40%), buffalo (6.89%), swine (5.03%), broiler chicken (3.80%), and horse (0.72%). However, in 2015, buffalo showed the highest EI (kgCO2eq/kg meat) by 6.44, followed by beef cattle (5.88), sheep (4.69), goat (4.07), swine (3.50), horse (3.09), and broiler chicken (0.38). EIs from swine, goat, sheep, broiler chicken, horse, beef cattle, and buffalo decreased by 60.77%, 58.59%, 46.68%, 21.30%, 18.15%, 19.94%, and 13.13% from 2000 to 2015, respectively. Results of GHG emissions and GHG EIs from each livestock category in Indonesia shown the improvement direction in order to mitigate GHG emission. Therefore, Indonesian government should focus on the beef cattle and buffalo that are a high contribution on GHG emissions and high EI by increasing the efficiency of livestock rearing management such as livestock health, genetic, diets, and environment.


Assuntos
Criação de Animais Domésticos , Gases de Efeito Estufa/análise , Gases de Efeito Estufa/prevenção & controle , Indústria Agropecuária , 34691 , Indonésia , Mudança Climática
9.
Sci. agric ; 75(1): 84-94, Jan.-Feb.2018.
Artigo em Inglês | VETINDEX | ID: biblio-1497680

Resumo

This paper aims to examine the issue raised by the consumption of locally produced food in all its various aspects, and in particular, addresses how this practice contributes to local and global sustainability. It analyzes the different definitions of local food, the strategies used, the implications of the distance traveled in the transportation of food to the consumer's table food miles, the relationships between local food consumption and sustainability, farming practices that reduce carbon emissions, contribution of urban agriculture to local food, local trading of food produced by rural farmers, as well as a number of relationships between the consumption of local food and human nutrition and health, local food protection and the ability to support local food production for humanitarian actions in disaster situations. The promotion of local food is a complex problem covering environmental issues, the economy and health. Transportation is not the only factor that determines how efficient it is to consume local food. Often, the technologies used for agricultural production are those most responsible for the degree of sustainability in the production and supply of food to the population. Local production does not always mean lower emissions of greenhouse gases. In general, the consumption of local foods, produced in ways adapted to the local environment using technologies with an ecological basis, is something beneficial and salutary for the environment, economy and society in general.


Assuntos
Agricultura Sustentável , Agricultura Urbana , Gases de Efeito Estufa , Ingestão de Alimentos , Abastecimento de Alimentos
10.
Sci. agric. ; 75(1): 84-94, Jan.-Feb.2018.
Artigo em Inglês | VETINDEX | ID: vti-13198

Resumo

This paper aims to examine the issue raised by the consumption of locally produced food in all its various aspects, and in particular, addresses how this practice contributes to local and global sustainability. It analyzes the different definitions of local food, the strategies used, the implications of the distance traveled in the transportation of food to the consumer's table food miles, the relationships between local food consumption and sustainability, farming practices that reduce carbon emissions, contribution of urban agriculture to local food, local trading of food produced by rural farmers, as well as a number of relationships between the consumption of local food and human nutrition and health, local food protection and the ability to support local food production for humanitarian actions in disaster situations. The promotion of local food is a complex problem covering environmental issues, the economy and health. Transportation is not the only factor that determines how efficient it is to consume local food. Often, the technologies used for agricultural production are those most responsible for the degree of sustainability in the production and supply of food to the population. Local production does not always mean lower emissions of greenhouse gases. In general, the consumption of local foods, produced in ways adapted to the local environment using technologies with an ecological basis, is something beneficial and salutary for the environment, economy and society in general.(AU)


Assuntos
Ingestão de Alimentos , Gases de Efeito Estufa , Agricultura Sustentável , Agricultura Urbana , Abastecimento de Alimentos
11.
Sci. agric ; 75(3): 255-272, mai.-jun. 2018. tab, graf
Artigo em Inglês | VETINDEX | ID: biblio-1497703

Resumo

The use of crop residues as a bioenergy feedstock is considered a potential strategy to mitigate greenhouse gas (GHG) emissions. However, indiscriminate harvesting of crop residues can induce deleterious effects on soil functioning, plant growth and other ecosystem services. Here, we have summarized the information available in the literature to identify and discuss the main trade-offs and synergisms involved in crop residue management for bioenergy production. The data consistently showed that crop residue harvest and the consequent lower input of organic matter into the soil led to C storage depletions over time, reducing cycling, supply and availability of soil nutrients, directly affecting the soil biota. Although the biota regulates key functions in the soil, crop residue can also cause proliferation of some important agricultural pests. In addition, crop residues act as physical barriers that protect the soil against raindrop impact and temperature variations. Therefore, intensive crop residue harvest can cause soil structure degradation, leading to soil compaction and increased risks of erosion. With regard to GHG emissions, there is no consensus about the potential impact of management of crop residue harvest. In general, residue harvest decreases CO2 and N2O emissions from the decomposition process, but it has no significant effect on CH4 emissions. Plant growth responses to soil and microclimate changes due to crop residue harvest are site and crop specific. Adoption of the best management practices can mitigate the adverse impacts of crop residue harvest. Longterm experiments within strategic production regions are essential to understand and monitor the impact of integrated agricultural systems and propose customized solutions for sustainable crop residue management in each region or landscape. Furthermore, private and public investments/cooperations are necessary for a better understanding of the potential environmental...


Assuntos
Gases de Efeito Estufa , Qualidade do Solo , Saccharum/química , Uso de Resíduos Sólidos , Produtos Agrícolas , Reciclagem
12.
Sci. agric. ; 75(3): 255-272, mai.-jun. 2018. tab, graf
Artigo em Inglês | VETINDEX | ID: vti-728730

Resumo

The use of crop residues as a bioenergy feedstock is considered a potential strategy to mitigate greenhouse gas (GHG) emissions. However, indiscriminate harvesting of crop residues can induce deleterious effects on soil functioning, plant growth and other ecosystem services. Here, we have summarized the information available in the literature to identify and discuss the main trade-offs and synergisms involved in crop residue management for bioenergy production. The data consistently showed that crop residue harvest and the consequent lower input of organic matter into the soil led to C storage depletions over time, reducing cycling, supply and availability of soil nutrients, directly affecting the soil biota. Although the biota regulates key functions in the soil, crop residue can also cause proliferation of some important agricultural pests. In addition, crop residues act as physical barriers that protect the soil against raindrop impact and temperature variations. Therefore, intensive crop residue harvest can cause soil structure degradation, leading to soil compaction and increased risks of erosion. With regard to GHG emissions, there is no consensus about the potential impact of management of crop residue harvest. In general, residue harvest decreases CO2 and N2O emissions from the decomposition process, but it has no significant effect on CH4 emissions. Plant growth responses to soil and microclimate changes due to crop residue harvest are site and crop specific. Adoption of the best management practices can mitigate the adverse impacts of crop residue harvest. Longterm experiments within strategic production regions are essential to understand and monitor the impact of integrated agricultural systems and propose customized solutions for sustainable crop residue management in each region or landscape. Furthermore, private and public investments/cooperations are necessary for a better understanding of the potential environmental...(AU)


Assuntos
Qualidade do Solo , Uso de Resíduos Sólidos , Gases de Efeito Estufa , Saccharum/química , Reciclagem , Produtos Agrícolas
13.
Vet. Not. (Online) ; 23(1): 39-70, jan.-abr. 2017.
Artigo em Português | VETINDEX | ID: biblio-1502469

Resumo

O objetivo da presente revisão é abordar as principais estratégias para mitigação da produção de metano (CH4) pelos animais ruminantes. Dentre as atividades antrópicas, a pecuária é apontada como uma das maiores responsáveis pelo aquecimento global, visto que os ruminantes são grandes produtores de metano, que é um dos principais gases do efeito estufa, sendo o que mais retém calor na atmosfera terrestre. A metanogênese ruminal ocorre por conta das condições fermentativas do ambiente ruminal, e sua produção, além de causar impactos ambientais também significa redução da eficiência energética da dieta, afetando diretamente a produtividade animal. O metano produzido pelos ruminantes é uma das poucas fontes desse gás passível de ser manipulada pelo homem. Por essa razão, várias pesquisas têm sido conduzidas na tentativa de reduzir a emissão de CH4 pelos animais ruminantes. Na tentativa de reduzir a metanogênese entérica, várias técnicas foram desenvolvidas, desde utilização de fármacos (ionóforos), como manipulação da dieta, incluindo carboidratos solúveis, forragem com maior digestibilidade e/ou com taninos e saponinas (fatores antinutricionais que manipulam a fermentação ruminal) e fontes de óleo. No entanto, cada técnica utilizada com a finalidade de reduzir a produção de metano ruminal, tem pontos pró e contra, que podem afetar negativamente a produção animal e até mesmo causar danos à saúde dos animais. Portanto, é necessário que se tomem cuidados quando se resolver adotar alguma das técnicas que visam mitigar a produção de CH4 entérico.


The objective of this review is to address the main strategies for mitigation of methane production by ruminants. Among the anthropogenic activities cattle ranching are considered one of the most responsible global warming. Given that, ruminants are major producers of methane, which is a major greenhouse gas, is what retains more heat in the atmosphere. The ruminal methanogenesis occurs on account of the rumen fermentation conditions, and its production besides causing environmental impacts, also means reducing the energy efficiency of the diet, directly affecting animal productivity. The methane produced by the ruminants is one of the few such sources capable of being manipulated by man gas. Therefore, various researches have been conducted in an attempt to reduce methane emission by ruminants. In an attempt to reduce methanogenesis enteric, several techniques have been developed from use of drugs (ionophore) as dietary manipulation, including soluble carbohydrate material with higher digestibility and / or tannins and saponins (antinutritional factors that manipulate rumen fermentation) and sources of oil. However, each technique in order to reduce ruminal methane production, has pro and con points which can adversely affect animal production and even cause damage to the health of animals. Therefore, it is necessary to take care when resolving to adopt some of the techniques to mitigate enteric methane production.


Assuntos
Animais , Bovinos , Aquecimento Global , Dieta/veterinária , Gases de Efeito Estufa , Metano/efeitos adversos , Rúmen/química
14.
Vet. Not. ; 23(1): 39-70, jan.-abr. 2017.
Artigo em Português | VETINDEX | ID: vti-18048

Resumo

O objetivo da presente revisão é abordar as principais estratégias para mitigação da produção de metano (CH4) pelos animais ruminantes. Dentre as atividades antrópicas, a pecuária é apontada como uma das maiores responsáveis pelo aquecimento global, visto que os ruminantes são grandes produtores de metano, que é um dos principais gases do efeito estufa, sendo o que mais retém calor na atmosfera terrestre. A metanogênese ruminal ocorre por conta das condições fermentativas do ambiente ruminal, e sua produção, além de causar impactos ambientais também significa redução da eficiência energética da dieta, afetando diretamente a produtividade animal. O metano produzido pelos ruminantes é uma das poucas fontes desse gás passível de ser manipulada pelo homem. Por essa razão, várias pesquisas têm sido conduzidas na tentativa de reduzir a emissão de CH4 pelos animais ruminantes. Na tentativa de reduzir a metanogênese entérica, várias técnicas foram desenvolvidas, desde utilização de fármacos (ionóforos), como manipulação da dieta, incluindo carboidratos solúveis, forragem com maior digestibilidade e/ou com taninos e saponinas (fatores antinutricionais que manipulam a fermentação ruminal) e fontes de óleo. No entanto, cada técnica utilizada com a finalidade de reduzir a produção de metano ruminal, tem pontos pró e contra, que podem afetar negativamente a produção animal e até mesmo causar danos à saúde dos animais. Portanto, é necessário que se tomem cuidados quando se resolver adotar alguma das técnicas que visam mitigar a produção de CH4 entérico.(AU)


The objective of this review is to address the main strategies for mitigation of methane production by ruminants. Among the anthropogenic activities cattle ranching are considered one of the most responsible global warming. Given that, ruminants are major producers of methane, which is a major greenhouse gas, is what retains more heat in the atmosphere. The ruminal methanogenesis occurs on account of the rumen fermentation conditions, and its production besides causing environmental impacts, also means reducing the energy efficiency of the diet, directly affecting animal productivity. The methane produced by the ruminants is one of the few such sources capable of being manipulated by man gas. Therefore, various researches have been conducted in an attempt to reduce methane emission by ruminants. In an attempt to reduce methanogenesis enteric, several techniques have been developed from use of drugs (ionophore) as dietary manipulation, including soluble carbohydrate material with higher digestibility and / or tannins and saponins (antinutritional factors that manipulate rumen fermentation) and sources of oil. However, each technique in order to reduce ruminal methane production, has pro and con points which can adversely affect animal production and even cause damage to the health of animals. Therefore, it is necessary to take care when resolving to adopt some of the techniques to mitigate enteric methane production.(AU)


Assuntos
Animais , Bovinos , Aquecimento Global , Metano/efeitos adversos , Gases de Efeito Estufa , Dieta/veterinária , Rúmen/química
15.
Sci. agric ; 72(2): 147-156, Mar.-Apr. 2015. tab, graf
Artigo em Inglês | VETINDEX | ID: biblio-1497477

Resumo

The large volume of sewage sludge (SS) generated with high carbon (C) and nutrient content suggests that its agricultural use may represent an important alternative to soil carbon sequestration and provides a potential substitute for synthetic fertilizers. However, emissions of CH4 and N2O could neutralize benefits with increases in soil C or saving fertilizer production because these gases have a Global Warming Potential (GWP) 25 and 298 times greater than CO2, respectively. Thus, this study aimed to determine C and N content as well as greenhouse gases (GHG) fluxes from soils historically amended with SS. Sewage sludge was applied between 2001 and 2007, and maize (Zea mays L.) was sowed in every year between 2001 and 2009. We evaluated three treatments: Control (mineral fertilizer), 1SS (recommended rate) and 2SS (double rate). Carbon stocks (0-40 cm) were 58.8, 72.5 and 83.1 Mg ha1in the Control, 1SS and 2SS, respectively, whereas N stocks after two years without SS treatment were 4.8, 5.8, and 6.8 Mg ha1, respectively. Soil CO2 flux was highly responsive to soil temperature in SS treatments, and soil water content greatly impacted gas flux in the Control. Soil N2O flux increased under the residual effects of SS, but in 1SS, the flux was similar to that found in moist tropical forests. Soil remained as a CH4sink. Large stores of carbon following historical SS application indicate that its use could be used as a method for carbon sequestration, even under tropical conditions.


Assuntos
Gases de Efeito Estufa , Poluentes do Solo , Sequestro de Carbono
16.
Sci. agric. ; 72(2): 147-156, Mar.-Apr. 2015. tab, graf
Artigo em Inglês | VETINDEX | ID: vti-30042

Resumo

The large volume of sewage sludge (SS) generated with high carbon (C) and nutrient content suggests that its agricultural use may represent an important alternative to soil carbon sequestration and provides a potential substitute for synthetic fertilizers. However, emissions of CH4 and N2O could neutralize benefits with increases in soil C or saving fertilizer production because these gases have a Global Warming Potential (GWP) 25 and 298 times greater than CO2, respectively. Thus, this study aimed to determine C and N content as well as greenhouse gases (GHG) fluxes from soils historically amended with SS. Sewage sludge was applied between 2001 and 2007, and maize (Zea mays L.) was sowed in every year between 2001 and 2009. We evaluated three treatments: Control (mineral fertilizer), 1SS (recommended rate) and 2SS (double rate). Carbon stocks (0-40 cm) were 58.8, 72.5 and 83.1 Mg ha1in the Control, 1SS and 2SS, respectively, whereas N stocks after two years without SS treatment were 4.8, 5.8, and 6.8 Mg ha1, respectively. Soil CO2 flux was highly responsive to soil temperature in SS treatments, and soil water content greatly impacted gas flux in the Control. Soil N2O flux increased under the residual effects of SS, but in 1SS, the flux was similar to that found in moist tropical forests. Soil remained as a CH4sink. Large stores of carbon following historical SS application indicate that its use could be used as a method for carbon sequestration, even under tropical conditions.(AU)


Assuntos
Gases de Efeito Estufa , Sequestro de Carbono , Poluentes do Solo
17.
Sci. agric ; 71(2): 157-162, Mar-Abr. 2014. tab, graf
Artigo em Inglês | VETINDEX | ID: biblio-1497394

Resumo

No-tillage in Brazil is an efficient agricultural system that improves crop productivity whilst controlling erosion caused to the soil by degradation. However, there is some concern regarding soil compaction. Our objective was to determine whether the function of soil structure in sustaining crop growth was dependent on row and interrow positions in long-term no-tillage. We took soil samples from a field in a commercial farm under long-term no-tillage since 1979 on a clayey Oxisol in Southern Brazil. We assessed soil physical quality using the revised Peerlkamp technique and measured bulk density, air-filled porosity and air permeability of intact soil cores. Samples were incubated to assess in vitro N2O and CO2 production. The soil physical and structural properties showed consistent differences between interrow and row positions, where the properties measured were more favorable. The revised Peerlkamp technique proved as efficient as quantitative parameters in discriminating treatment differences. Overall, soil physical conditions in the interrow were less favourable than in the row. Pore continuity did not vary as regards position. This may explain why row position did not influence in vitro N2O and CO2 production. Soil physical quality under no-tillage system is enhanced, at least in the short term, by superficial disturbances in the row as a result of the action of the coulters of the no-tillage seeder.


Assuntos
Características do Solo , Condições do Solo , 24444 , Gases de Efeito Estufa , Erosão do Solo
18.
Sci. Agric. ; 71(2): 157-162, Mar-Abr. 2014. tab, graf
Artigo em Inglês | VETINDEX | ID: vti-27522

Resumo

No-tillage in Brazil is an efficient agricultural system that improves crop productivity whilst controlling erosion caused to the soil by degradation. However, there is some concern regarding soil compaction. Our objective was to determine whether the function of soil structure in sustaining crop growth was dependent on row and interrow positions in long-term no-tillage. We took soil samples from a field in a commercial farm under long-term no-tillage since 1979 on a clayey Oxisol in Southern Brazil. We assessed soil physical quality using the revised Peerlkamp technique and measured bulk density, air-filled porosity and air permeability of intact soil cores. Samples were incubated to assess in vitro N2O and CO2 production. The soil physical and structural properties showed consistent differences between interrow and row positions, where the properties measured were more favorable. The revised Peerlkamp technique proved as efficient as quantitative parameters in discriminating treatment differences. Overall, soil physical conditions in the interrow were less favourable than in the row. Pore continuity did not vary as regards position. This may explain why row position did not influence in vitro N2O and CO2 production. Soil physical quality under no-tillage system is enhanced, at least in the short term, by superficial disturbances in the row as a result of the action of the coulters of the no-tillage seeder.(AU)


Assuntos
Características do Solo , Condições do Solo , Gases de Efeito Estufa , 24444 , Erosão do Solo
19.
Braz. J. Biol. ; 73(4): 753-764, Nov. 2013. mapas, ilus, tab, graf
Artigo em Inglês | VETINDEX | ID: vti-31066

Resumo

For almost two decades, studies have been under way in Brazil, showing how hydroelectric reservoirs produce biogenic gases, mainly methane (CH4) and carbon dioxide (CO2), through the organic decomposition of flooded biomass. This somewhat complex phenomenon is due to a set of variables with differing levels of interdependence that directly or indirectly affect greenhouse gas (GHG) emissions. The purpose of this paper is to determine, through a statistical data analysis, the relation between CO2, CH4 diffusive fluxes and environmental variables at the Furnas, Itumbiara and Serra da Mesa hydroelectric reservoirs, located in the Cerrado biome on Brazil's high central plateau. The choice of this region was prompted by its importance in the national context, covering an area of some two million square kilometers, encompassing two major river basins (Paraná and Tocantins-Araguaia), with the largest installed power generation capacity in Brazil, together accounting for around 23% of Brazilian territory. This study shows that CH4 presented a moderate negative correlation between CO2 and depth. Additionally, a moderate positive correlation was noted for pH, water temperature and wind. The CO2 presented a moderate negative correlation for pH, wind speed, water temperature and air temperature. Additionally, a moderate positive correlation was noted for CO2 and water temperature. The complexity of the emission phenomenon is unlikely to occur through a simultaneous understanding of all the factors, due to difficulties in accessing and analyzing all the variables that have real, direct effects on GHG production and emission.(AU)


Há quase duas décadas, no Brasil, vêm sendo realizados estudos que revelam que os reservatórios hidrelétricos produzem gases biogênicos, principalmente o metano (CH4) e o dióxido de carbono (CO2), provenientes da decomposição orgânica da biomassa alagada. Observa-se que esse fenômeno é bastante complexo devido a uma gama de variáveis que possuem diferentes graus de interdependência e que influenciam diretamente ou indiretamente nas emissões de gases de efeito estufa (GEE). O objetivo deste trabalho é determinar o grau de relacionamento entre os fluxos difusivos de CO2, CH4 e variáveis ambientais dos Reservatórios Hidrelétricos de Furnas, Itumbiara e Serra da Mesa, através da análise estatística dos dados. Os reservatórios hidrelétricos estão situados no Bioma Cerrado, localizado no Planalto Central do Brasil. A escolha da região deu-se devido a sua importância no contexto nacional, já que corresponde a uma área de aproximadamente dois milhões de quilômetros quadrados, e, nela estão inseridas duas bacias (Bacia do Paraná e Bacia do Tocantins-Araguaia), com a maior capacidade instalada de energia elétrica do país. Esta duas bacias juntas abrangem 23% do território nacional. Neste estudo os resultados revelam que o CH4 apresentou correlação negativa, significativa e moderada com o CO2 e com a profundidade. Observou-se ainda correlação positiva e moderada com pH, temperatura da água e velocidade do vento. O CO2 apresentou correlação negativa, significativa e moderada com pH, com a velocidade do vento, temperatura da água e temperatura do ar. Observou-se também correlação positiva e moderada do CO2 com a temperatura da água. A complexidade do fenômeno de emissão dificilmente ocorrerá pelo entendimento simultâneo de todos os fatores, devido às dificuldades de acessar e analisar todas as variáveis que realmente têm implicação direta nesta produção/emissão de GEE.(AU)


Assuntos
Gases de Efeito Estufa , Reservatórios de Água , Metano , Dióxido de Carbono , Brasil
20.
Braz. j. biol ; 73(4): 753-764, 1jan. 2013. map, ilus, tab, graf
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1468142

Resumo

For almost two decades, studies have been under way in Brazil, showing how hydroelectric reservoirs produce biogenic gases, mainly methane (CH4) and carbon dioxide (CO2), through the organic decomposition of flooded biomass. This somewhat complex phenomenon is due to a set of variables with differing levels of interdependence that directly or indirectly affect greenhouse gas (GHG) emissions. The purpose of this paper is to determine, through a statistical data analysis, the relation between CO2, CH4 diffusive fluxes and environmental variables at the Furnas, Itumbiara and Serra da Mesa hydroelectric reservoirs, located in the Cerrado biome on Brazil's high central plateau. The choice of this region was prompted by its importance in the national context, covering an area of some two million square kilometers, encompassing two major river basins (Paraná and Tocantins-Araguaia), with the largest installed power generation capacity in Brazil, together accounting for around 23% of Brazilian territory. This study shows that CH4 presented a moderate negative correlation between CO2 and depth. Additionally, a moderate positive correlation was noted for pH, water temperature and wind. The CO2 presented a moderate negative correlation for pH, wind speed, water temperature and air temperature. Additionally, a moderate positive correlation was noted for CO2 and water temperature. The complexity of the emission phenomenon is unlikely to occur through a simultaneous understanding of all the factors, due to difficulties in accessing and analyzing all the variables that have real, direct effects on GHG production and emission.


Há quase duas décadas, no Brasil, vêm sendo realizados estudos que revelam que os reservatórios hidrelétricos produzem gases biogênicos, principalmente o metano (CH4) e o dióxido de carbono (CO2), provenientes da decomposição orgânica da biomassa alagada. Observa-se que esse fenômeno é bastante complexo devido a uma gama de variáveis que possuem diferentes graus de interdependência e que influenciam diretamente ou indiretamente nas emissões de gases de efeito estufa (GEE). O objetivo deste trabalho é determinar o grau de relacionamento entre os fluxos difusivos de CO2, CH4 e variáveis ambientais dos Reservatórios Hidrelétricos de Furnas, Itumbiara e Serra da Mesa, através da análise estatística dos dados. Os reservatórios hidrelétricos estão situados no Bioma Cerrado, localizado no Planalto Central do Brasil. A escolha da região deu-se devido a sua importância no contexto nacional, já que corresponde a uma área de aproximadamente dois milhões de quilômetros quadrados, e, nela estão inseridas duas bacias (Bacia do Paraná e Bacia do Tocantins-Araguaia), com a maior capacidade instalada de energia elétrica do país. Esta duas bacias juntas abrangem 23% do território nacional. Neste estudo os resultados revelam que o CH4 apresentou correlação negativa, significativa e moderada com o CO2 e com a profundidade. Observou-se ainda correlação positiva e moderada com pH, temperatura da água e velocidade do vento. O CO2 apresentou correlação negativa, significativa e moderada com pH, com a velocidade do vento, temperatura da água e temperatura do ar. Observou-se também correlação positiva e moderada do CO2 com a temperatura da água. A complexidade do fenômeno de emissão dificilmente ocorrerá pelo entendimento simultâneo de todos os fatores, devido às dificuldades de acessar e analisar todas as variáveis que realmente têm implicação direta nesta produção/emissão de GEE.


Assuntos
Dióxido de Carbono , Gases de Efeito Estufa , Metano , Reservatórios de Água , Brasil
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