RESUMO O objetivo deste estudo foi avaliar os efeitos de inclusões crescentes de Tribulus terrestris (TT) em dietas para ovinos confinados, sobre parâmetros ruminais e metabólitos sanguíneos. O experimento foi conduzido em duas etapas: in vitro, com inclusões que variaram de 0 até 15,0g/kg de TT na matéria seca da dieta, sendo determinadas as digestibilidades in vitro da matéria seca e dos nutrientes, do pH, da mensuração de nitrogênio amoniacal e dos gases de efeito estufa; e in situ, com inclusões de 0 até 5,0g/kg, no qual cinco ovinos canulados foram distribuídos em um delineamento de quadrado latino 5 × 5. Foram avaliados parâmetros fermentativos, populações de protozoários e perfil metabólico sanguíneo. A inclusão de TT, independentemente da dosagem, proporcionou redução na digestibilidade in vitro, com efeito quadrático sobre matéria seca e nutrientes, diminuições do nitrogênio amoniacal e metano. Em termos de parâmetros fermentativos, as dosagens mais seguras in vitro foram 1,25 e 2,5g/kg. A inclusão de até 5,0 g/kg não afetou os parâmetros fermentativos in situ, não prejudicou o perfil metabólico sanguíneo e reduziu a população de pequenos protozoários. Estudos com inclusões maiores que 5,0g/kg devem ser efetuados para confirmar o efeito sobre os protozoários, com posteriores análises de desempenho produtivo.

ABSTRACT The aim was to evaluate the effects of increasing levels of Tribulus terrestris (TT) in diets of sheep in confinement on rumen parameters and blood metabolites. The experiment was conducted in two stages, in vitro, with inclusions ranging from 0 to 15.0 g/kg of TT in dry matter of the diet and the in vitro digestibility of dry matter and nutrients, pH, measurement of ammoniacal nitrogen and greenhouse gases were determined. And in situ, with inclusions of 0 to 5.0g/kg, in which five cannulated sheep were distributed in a 5 × 5 Latin square design to evaluate fermentation parameters, protozoan populations and blood metabolic profile. The inclusion of TT, regardless of dosage, resulted in decrease on in vitro digestibility, with quadratic effect on dry matter and nutrients, and reduction in ammoniacal nitrogen and methane. In terms of fermentation parameters, the safest dosages in vitro were 1.25 and 2.5g/kg. Inclusion of up to 5.0g/kg did not affect fermentation parameters in situ, did not harm the blood metabolic profile and reduced the population of small protozoa. Studies with inclusions greater than 5.0g/kg should be carried out to confirm the effect on protozoa, with subsequent analysis of production performance.

Resumo A complexa interação entre parasitas gastrointestinais e hospedeiros ovinos envolve comunidades de bactérias, gêneros de parasitas, genes parasitários e vias biológicas. Haemonchus contortus representa um desafio global para ruminantes, e a comunidade bacteriana pode influenciar a resistência e a suscetibilidade a esses parasitas. Assim, uma melhor compreensão dessa complexa interação pode contribuir para o desenvolvimento de uma nova abordagem para o controle desse parasito. Este estudo avaliou a comunidade bacteriana em ovinos Corriedale, naturalmente infectados com H. contortus, classificados em baixas cargas parasitárias (LC), intermediárias (IC) ou altas (HC), ao longo de dez meses. Amostras de fezes foram coletadas mensalmente para a contagem de ovos (OPG), e o sequenciamento do gene 16S rRNA foi realizado em cinco animais de cada grupo. O OPG médio foi de 2.635 ± 105 para HC, 845 ± 129 para IC e 110 ± 70 para LC, com uma diferença significativa (p = 0,0001). Firmicutes, Proteobacteria e Spirochaetes foram mais abundantes no grupo HC. 102 gêneros bacterianos apresentaram diferenças significativas entre os grupos LC e HC. A Beta diversidade foi estatisticamente diferente (p<0,005) para HC em comparação com os outros dois grupos. Também encontraram-se comunidades diferentes entre LC e HC. Sediminispirochaeta, Oribacterium, Alloprevotella, Prevotellaceae_UCG-001, Prevotellaceae_UCG-003, Ruminiclostridium_6 e Ruminococcus_1 foram significativamente mais abundantes no grupo LC e IC. Acetobacter e Methanocorpusculum tiveram uma redução significativa no grupo LC. Gêneros bacterianos relacionados à baixa emissão de metano e melhor eficiência alimentar estavam significativamente presentes no grupo LC. Portanto, uma melhor compreensão do papel da interação hospedeiro-parasita pode contribuir para melhorar o controle de H. contortus.

Abstract A complex interaction of gastrointestinal parasites with sheep hosts may involve bacteria communities, parasite genera, parasitic genes, and biological pathways. Haemonchus contortus presents a global challenge for ruminants, and the bacterial community can influence sheep's resistance and susceptibility to these parasites. Thus, a better understanding of this complex interaction could contribute to the development of a new approach to parasite control. This study evaluated the bacterial community of Corriedale sheep naturally infected with H. contortus based on the fecal egg counts over ten months and then classified as having low (LC), intermediate (IC), or high (HC). Stool samples were collected monthly for egg counts (EPG), and 16S rRNA gene sequencing was performed on five animals from each group. The average EPG was 2,635 ± 105 for HC, 845 ± 129 for IC, and 110 ± 70 for LC, with a significant difference (p = 0.0001). Firmicutes, Proteobacteria, and Spirochaetes were more abundant in the HC group. 102 bacterial genera showed significant differences between the LC and HC groups. Beta diversity was statistically different (p<0.005) for HC compared with the other two groups; also, different communities were found between LC and HC. Sediminispirochaeta, Oribacterium, Alloprevotella, Prevotellaceae_UCG-001, Prevotellaceae_UCG-003, Ruminiclostridium_6 and Ruminococcus_1were significant more abundant in LC, and IC group. Acetobacter and Methanocorpusculum had a significant reduction in the LC group. Thus, bacterial genera related to low methane emission and food efficiency were significantly present in the LC group. Therefore, a better understanding of the role of host-bacterial community-parasite interaction could contribute to improving parasite control management.

RESUMO Santa Catarina é um importante produtor de banana, responsável por 722 toneladas anuais. Para cada 1.000 kg de banana colhida, são gerados aproximadamente 3.000 kg de pseudocaule, 650 kg de cascas e 350 kg de frutos rejeitados. Estudos avaliaram a utilização de resíduos de banana para produção de bioetanol. Resíduos sólidos como bagaço de pseudocaule de banana, cascas de banana e vinhaça (resíduo de caldo fermentado) são produzidos nesse processo. Este estudo teve como objetivo quantificar e caracterizar esses resíduos para produção de biogás e metano. Cascas de banana e vinhaça foram melhores por conterem menor teor de sólidos totais e relações C:N (carbono:nitrogênio) favoráveis (10 - 30:1), proporcionando maior potencial bioquímico de metano (260 mLCH4 gvs -1) em comparação ao pseudocaule de bananeira bagaço (201 mLCH4 gvs -1). No entanto, a vinhaça apresentou alto teor de sulfeto de hidrogênio (0,0783%), necessitando de dessulfurização do biogás gerado para seu uso seguro. No geral, os resultados indicam que o bagaço do pseudocaule da banana, as cascas de banana e a vinhaça têm potencial substancial para a produção de biogás e metano devido às suas altas taxas de degradação. A composição do biogás atende aos critérios de utilização, com concentrações adequadas de metano e dióxido de carbono, destacando a viabilidade desses resíduos para geração de energia e contribuindo para a sustentabilidade no cultivo da banana. 72 anuais 1000 1 000 1.00 colhida 3000 3 3.00 65 35 rejeitados bioetanol resíduo fermentado processo CN C N carbononitrogênio carbono nitrogênio (carbono:nitrogênio 10 (1 301, 301 30 , 30:1) 260 (26 mLCH -1 201 (20 1. . entanto 0,0783%, 00783 0,0783% 0 0783 (0,0783%) seguro geral degradação 7 100 00 1.0 300 3.0 6 ( 30:1 26 (2 20 0078 0,0783 078 (0,0783% 3. 30: 2 007 0,078 07 (0,0783 0,07 (0,078 0,0 (0,07 0, (0,0 (0, (0

ABSTRACT Santa Catarina is a significant banana producer, responsible for 722 tons annually. For every 1,000 kg of bananas harvested, approximately 3,000 kg of pseudostem, 650 kg of peels, and 350 kg of rejected fruit are generated. Studies have evaluated the use of banana residues for bioethanol production. Solid residues like banana pseudostem bagasse, banana peels, and vinasse (fermented broth residue) are produced during this process. This study aimed to quantify and characterize these residues for biogas and methane production. Banana peels and vinasse were more suitable for containing lower total solids content and favorable C:N (carbon:nitrogen) ratios (10-30:1), yielding higher biochemical potential of methane (260 mLCH4 gvs -1) compared to banana pseudostem bagasse (201 mLCH4 gvs -1). However, vinasse had a high hydrogen sulfide content (0.0783%), necessitating desulphurization for safe biogas use. The results indicate that banana pseudostem bagasse, banana peels, and vinasse have substantial potential for biogas and methane production due to their high degradation rates. The biogas composition meets the criteria for use, with adequate methane and carbon dioxide concentrations, highlighting the viability of these residues for energy generation and contributing to sustainability in banana cultivation. producer 72 annually 1000 1 000 1,00 harvested 3000 3 3,00 65 35 generated fermented residue process CN C N carbonnitrogen nitrogen (carbon:nitrogen 10301, 10301 10 30 , (10-30:1) 260 (26 mLCH -1 201 (20 1. . However 0.0783%, 00783 0.0783% 0 0783 (0.0783%) rates concentrations cultivation 7 100 00 1,0 300 3,0 6 1030 (10-30:1 26 (2 - 20 0078 0.0783 078 (0.0783% 1, 3, 103 (10-30: 2 ( 007 0.078 07 (0.0783 (10-30 0.07 (0.078 (10-3 0.0 (0.07 (10- 0. (0.0 (10 (0. (1 (0

Resumen Introducción: Las arqueas metanogénicas (MA) participan en la mineralización anaerobia de la materia orgánica en sedimentos de manglar, su actividad está relacionada con el calentamiento atmosférico por la producción de metano; diversas variables ambientales pueden influir en la dinámica metanogénica y la producción de metano en estos sedimentos. Objetivo: Analizar, mediante técnicas dependientes de cultivo, la abundancia de las arqueas metanógenas viables (AMV) y la producción de metano en diferentes épocas climáticas en los sedimentos del manglar El Morro-La Mancha, Veracruz, Golfo de México. Métodos: De mayo a noviembre 2019, siguiendo un transecto de salinidad, se recolectaron sedimentos del manglar del Morro-La Mancha, en tres localidades, abarcando tres diferentes épocas climáticas, secas (mayo), lluvias (octubre) y nortes (noviembre) (N = 9), cuantificándose la abundancia de las AMV mediante la técnica del Número Más Probable (NMP) con acetato y metanol como substratos; la influencia de los sulfatos en la producción de metano a partir de acetato en microcosmos, se analizó por cromatografía de gases y se evaluaron las variables químicas de salinidad, pH, Eh, carbohidratos, contenido orgánico y carbonatos en los sedimentos. Resultados: Se determinó una abundancia de AMV de 102 a 108 NMP/g de sedimento húmedo, superior a la reportada en otros estudios, dicha abundancia se incrementó cuando se utilizó metanol (104-108 NMP/g sedimento) como sustrato, en comparación con el acetato (102-105 NMP/g sedimento); la producción de metano en los microcosmos aumentó en condiciones libres de sulfatos (29.78-929.75 nmol CH4/mes) y en los sedimentos de la temporada de lluvias. Conclusión: Se destaca la influencia de las condiciones químicas de los sedimentos del manglar sobre la dinámica metanógena, determinándose que, en la temporada de lluvias, una disminución de la salinidad, Eh más electronegativos y el incremento de las fracciones orgánicas favorecieron la metanogénesis.

Abstract Introduction: Methanogenic archaea (MA), participate in the anaerobic mineralization of organic matter in mangrove sediments, their activity is related to atmospheric warming due to the production of methane; several environmental variables can influence the presence of MA and methane production in these sediments. Objective: To analyze, through culture-dependent techniques, viable methanogenic archaea (VMA) in the sediments, and the production of methane from acetate in different climatic periods in the mangrove El Morro-La Mancha, Veracruz, Gulf of Mexico. Methods: From May to November 2019, following a salinity transect, sediment samples from El Morro-La Mancha mangrove were collected at three locations, in three different climatic seasons, dry (May), rainy (October) and northern (November) (N = 9). VMA in the sediments was quantified using the Most Probable Number (MPN) technique with acetate and methanol as substrates. The influence of sulfate on methane production was analyzed from acetate in microcosm by gas chromatography and the chemical variables of salinity, pH, Eh, carbohydrates, organic content, and carbonates in the sediments were evaluated. Results: The abundance of VMA was 102 to 108 MPN/g of wet sediment, higher than that reported in other studies, this abundance was higher when methanol (104-108 MPN/g sediment) was used as substrate, compared to acetate (102-105 MPN/g sediment); methane production in the microcosms increased in sulfate-free conditions (29.78-929.75 nmol CH4/month) and in the sediments of the rainy season. Conclusion: The influence of the chemical conditions of the mangrove sediments on the methanogenic dynamics is highlighted, determining that in the rainy season, the decrease in salinity, more electronegative Eh, and the increase in organic fractions favored the methanogenesis.

ABSTRACT Ecuador is some country rich in agricultural biomass that is not used at all. But this type of biomass has an ecological value that can impact the diet of the Ecuadorian population. What is viable is the use of urban biomass as a raw material to produce sustainable green hydrogen. The methodology is based on qualitative research (qualitative exegetical content) and quantitative research (elementary analysis of the substrate). The sample was 296 homes whose organic bio-waste was analyzed to determine the theoretical percentage of CH4. The results allowed us to obtain the stoichiometric equations of CH4, in which a value of 49,6% was found, and a PCI of 3878,77 kcal/kg. It is concluded that the intra-domestic urban biomass generated in Guayaquil homes can be replaced with an 80,74% possibility of being used to produce green hydrogen by applying biological technology (dark fermentation). Combining both technologies (hydrogen and biomass) contribute to reducing energy dependence on fossil fuels and water to generate electricity and reducing the carbon footprint by promoting circular, sustainable and sustainable energy production.

RESUMEN Ecuador es un país rico en biomasa agrícola que no se usa del todo. Pero este tipo de biomasa tiene un valor ecológico que pueden repercutir en la alimentación de la población ecuatoriana. Lo viable es el uso de la biomasa urbana como materia prima para producir hidrógeno verde sostenible. La metodología se basa en una investigación cualitativa (contenido exegético cualitativo) y cuantitativa (análisis elemental del sustrato). La muestra fue de 286 hogares cuyos biorresiduos orgánicos se analizaron para determinar el porcentaje teórico de metano e hidrógeno verde. Los resultados permitieron obtener las ecuaciones estequiométricas del CH4 en lo que se hallaron un valor de 49,6%, y un PCI de 3878,77 kcal/kg. Se concluye que la biomasa urbana intradomiciliaria que se genera en los hogares guayaquileños y en las diferentes ciudades principales de Ecuador tiene un 80,74 % de posibilidad de usarse para producción H2 aplicando la tecnología biológica (fermentación oscura). Combinando ambas tecnologías (hidrógeno y biomasa) se contribuye a la disminución de dependencia energética de combustibles fósiles e hídricos para generar electricidad y disminución de la huella de carbono fomentando una producción energética circular, sostenible y sustentable.

Abstract Introduction: Outdoor garbage disposal and accumulation sites concentrate water, soil and atmospheric pollution; however, there is little information on this problem in Ecuador. Objective: Assess the environmental impact, including methane emissions, from the open-air garbage dump in Naranjito, Ecuador. Methods: To determine the methane emission rate from solid waste biomass, we applied the static camera method, with a portable device, for 15 continuous days (May-June 2023) and at 08:00, 12:30 and 16:00. For the qualitative evaluation of environmental impact, we used the Global Index weighting, based on the impacts generated in the physical and perceptual environment. Results: The global Index was 53,3, i.e. critical impact; mean emission rate was 858,8mg/m2/h, higher than the emission rate of the surrounding soil (133,4mg/m2/h; p<0,05). Conclusion: A sustainable management alternative is urgent to reduce the methane emission rate in Naranjito.

Resumen Introducción: Los sitios de eliminación y acumulación de basura al aire libre concentran la contaminación del agua, el suelo y el aire; sin embargo, hay poca información sobre este problema en Ecuador. Objetivo: Evaluar el impacto ambiental, incluidas las emisiones de metano, del vertedero al aire libre en Naranjito, Ecuador. Métodos: Para determinar la tasa de emisión de metano de la biomasa de residuos sólidos, aplicamos el método de cámara estática, con un dispositivo portátil, durante 15 días continuos (mayo- junio 2023) a las 08:00, 12:30 y 16:00. Para la evaluación cualitativa del impacto ambiental utilizamos la ponderación del Índice Global, basada en los impactos generados en el entorno físico y perceptual. Resultados: El Índice Global fue de 53,3, es decir, impacto crítico; la tasa media de emisión fue de 858,8mg/m²/h, superior a la tasa de emisión del suelo circundante (133,4mg/m²/h; p<0,05). Conclusión: Es urgente una alternativa de gestión sostenible para reducir la tasa de emisión de metano en Naranjito.

RESUMO A destinação adequada dos resíduos de frutas e vegetais é fundamental para promover a sustentabilidade ambiental, reduzir a pegada de carbono, melhorar a qualidade do solo e contribuir para a transição para uma economia circular. Neste estudo, foram avaliados os efeitos da adição de água residuária da bovinocultura de leite em codigestão anaeróbia com resíduos de frutas e vegetais e o uso do biofertilizante como diluente na monodigestão anaeróbia dos resíduos de frutas e vegetais (reciclo). A produção específica de biogás e metano, bem como a qualidade agronômica do biofertilizante em um estudo semicontínuo, foram avaliados. Foram utilizadas duas estratégias para partida dos reatores: o abastecimento inicial dos reatores totalmente com inóculo (biofertilizante proveniente da digestão anaeróbia da água residuária da bovinocultura de leite) e a progressão de carga para os resíduos de frutas e vegetais. A maior produção específica de biogás e metano foi atingida pela codigestão anaeróbia de resíduos de frutas e vegetais com água residuária da bovinocultura de leite, 720 e 436 L kg-1 de sólidos voláteis (SV), respectivamente. A adição da água residuária da bovinocultura de leite aumentou em 249% a alcalinidade dos resíduos de frutas e vegetais e diminuiu em 83,4% sua acidez volátil. A recuperação de macronutrientes no biofertilizante é favorecida pela monodigestão anaeróbia dos resíduos de frutas e vegetais em função do uso do reciclo. Entretanto, visando a destinação destes ao meio rural, a codigestão anaeróbia com água residuária da bovinocultura de leite favorece o uso agrícola do biofertilizante. ambiental carbono circular reciclo . (reciclo) semicontínuo 72 43 kg1 kg 1 kg- SV, SV , (SV) respectivamente 249 834 83 4 83,4 volátil Entretanto rural (reciclo 7 (SV 24 8 83, 2

ABSTRACT The proper disposal of fruit and vegetable waste is essential to promote environmental sustainability, reduce the carbon footprint, improve soil quality, and contribute to the transition to a circular economy. This study examined the impact of incorporating dairy cattle wastewater (DCWW) into anaerobic co-digestion with fruit and vegetable residues and utilization of the resulting biofertilizer as a diluent in the anaerobic mono-digestion of fruit and vegetable residues (recycle). The specific biogas and methane production and the agronomic quality of the biofertilizer were evaluated in a semi-continuous trial. Two startup strategies were employed: initially, the reactors were entirely fed with inoculum (biofertilizer derived from DCWW), and fruit and vegetable residue feedstock was gradually introduced. Anaerobic co-digestion of fruit and vegetable residues with DCWW yielded the highest specific production of biogas and methane at 720 and 436 L kg-1 of volatile solids (VS), respectively. The addition of DCWW increases fruit and vegetable residue alkalinity by 249% and reduces the volatile acidity by 83.4%. Anaerobic mono-digestion of fruit and vegetable residues enhances macronutrient recovery in the biofertilizer through recycle. Logistically, directing fruit and vegetable residues to rural areas for anaerobic co-digestion with DCWW promotes agricultural biofertilizer use. sustainability footprint economy (DCWW codigestion co digestion monodigestion mono recycle . (recycle) semicontinuous semi continuous trial employed initially DCWW, , DCWW) introduced 72 43 kg1 kg 1 kg- VS, VS (VS) respectively 249 834 83 4 83.4% Logistically use (recycle 7 (VS 24 8 83.4 2 83.

Resumen El estudio evalúa la generación y capacidad de recuperación de metano en el Relleno Sanitario de Villavicencio, Colombia, mediante el modelo LandGEM. En donde se observa un aumento significativo en la generación de metano, pasando de alrededor de 1,5 millones de metros cúbicos en 2010 a más de 8,5 millones en 2020, lo que indica una creciente urgencia por implementar medidas de mitigación efectivas. Se estimó que, para el año 2042, la producción de energía eléctrica del metano podría ser de 248.067 kW/día, capaz de abastecer a unos 43.705 hogares mensualmente. Asimismo, se generaría energía térmica de 468.572 kWh/día, útil para procesos industriales. Se plantearon escenarios de gestión, donde, por ejemplo, la optimización operacional podría aumentar la producción eléctrica a 342.333 kW/día, beneficiando a más de 60.000 hogares mensualmente. Las conclusiones resaltan la correlación directa entre la cantidad de residuos y la generación de metano, y el significativo potencial de convertir estas emisiones en energía, apuntando hacia la autosuficiencia y sostenibilidad energética regional. El aprovechamiento del metano representa una alternativa valiosa frente a la dependencia de combustibles fósiles y para el desarrollo de una economía circular.

Abstract The study evaluates the generation and recovery capacity of methane at the Villavicencio Landfill in Colombia, using the LandGEM model. It shows a significant increase in methane generation, rising from about 1.5 million cubic meters in 2010 to over 8.5 million in 2020, indicating a growing urgency to implement effective mitigation measures. It was estimated that by the year 2042, the electrical energy production from methane could be 248.067 kW/day, capable of supplying about 43.705 homes monthly. Additionally, thermal energy generation would be 468.572 kWh/day, useful for industrial processes. Management scenarios were proposed, where, for example, operational optimization could increase electric production to 342.333 kW/day, benefiting more than 60.000 homes monthly. The conclusions highlight the direct correlation between the amount of waste and methane generation, and the significant potential for converting these emissions into energy, pointing towards regional energy self-sufficiency and sustainability. Methane recovery represents a valuable alternative to the dependence on fossil fuels and for the development of a circular economy.

RESUMEN La economía colombiana depende en gran medida de los ingresos del sector combustibles. Uno de los procesos fundamentales en la cadena de los combustibles limpios corresponde al reformado de metano con vapor (SMR), que genera H2 necesario en la producción de combustibles bajos en azufre. La identificación de oportunidades para incrementar H2 implica el análisis de variables que afectan el suministro de calor en el horno SMR (precalentamiento-reacción), Este documento presenta los resultados de un análisis del suministro de calor en un horno industrial SMR mediante análisis de datos y simulación con Aspen HYSYS. Para esto, los históricos de ocho años de operación fueron analizados con el algoritmo kmeans, La simulación fue validada con datos de diseño, comparada con los históricos y aplicada para explorar la superficie operativa del horno, Según los resultados, el análisis por kmeans dividió los datos en dos modos de operación, que fueron representativos para el horno; un modo mostró la mayor producción de H2. Asimismo, los resultados de la simulación sugirieron que el incremento en la generación de H2 fue estabilizada en valores elevados tanto en flujo de calor como flujo de gas natural, tendiendo hacia un valor de estado estacionario

ABSTRACT Colombian economy depends largely on income from the fuel sector. A fundamental process in the clean-fuels chain corresponds to the steam methane reforming (SMR), which generates the hydrogen needed for production of low-sulphur fuels. The identification of opportunities to increase hydrogen production involves the analysis of variables that affects heat supply in the SMR furnace (preheating and reaction section). This document presents the main results of an analysis of heat supply in an industrial SMR furnace based on both, data analysis and simulation with Aspen HYSYS. To such end, eight-year-process-operation data were collected and analysed with kmeans multivariate algorithm. The simulation was validated with pertinent design data and compared to process data. Next, the simulation was applied to explore the operating surface of the furnace to identify conditions with major hydrogen production. According to the results, the statistical analysis by kmeans divided the data into two operational modes that were representative for the furnace; one of them showed the major H2 production. Similarly, the simulation results suggested that the increase in H2 generation was stabilized with the highest values of both heat and natural gas, tending towards a steady state value.

ABSTRACT "In Cuba, agriculture is responsible for 20% of Greenhouse Gas emissions, making it the second largest emitting sector. This research aims to estimate the Greenhouse Gas emissions in the Agriculture sector in the province of Cienfuegos in the period 2010-2020. The methodologies used were the Guidelines of the Intergovernmental Panel on Climate Change of 2006. In 2020, the GHG emissions from the Agriculture sector in the province of Cienfuegos were 309.4 Gg CO2eq (representing a 28.9% decrease compared to 2010). Of these emissions, 60.3% corresponded to methane (CH4), 39.5% to nitrous oxide (N2O), and the remaining 0.1% to carbon dioxide (CO2). CH4 emissions amounted to 186.9 Gg CO2eq and mainly came from enteric fermentation of livestock, which contributed 169.0 Gg CO2eq (90.5% of the total). N2O emissions from the sector amounted to 116.9 Gg CO2eq and mainly came from activities related to agricultural soils, with direct livestock excreta in pastures being the subcategory that contributed the most N2O in the province with 81.3 Gg CO2eq, representing 69.6% of the total. Finally, CO2 emissions solely came from the application of urea. The emissions inventory of the Agriculture sector in the province of Cienfuegos is a valuable tool for making local-level decisions, prioritizing mitigation actions and measures in line with national goals, supporting development, as well as implementing and monitoring the impact of such actions."

RESUMEN En Cuba la agricultura es responsable del 20% de las emisiones de Gases de Efecto Invernadero, siendo el segundo sector más emisor. Esta investigación tiene como objetivo estimar las emisiones de Gases de Efecto Invernadero en el sector Agricultura en la provincia de Cienfuegos en el período 2010-2020. Se utilizaron como metodologías las Directrices del Panel Intergubernamental sobre Cambio Climático del 2006. En 2020, las emisiones de GEI del sector Agricultura en la provincia de Cienfuegos, fueron de 309.4 Gg CO2eq (representa un 28.9% menor que el año 2010). Del total de estas emisiones, el 60.3% correspondió al metano (CH4), el 39.5% al óxido nitroso (N2O) y el restante 0.1% al dióxido de carbono (CO2). Las emisiones de CH4 ascienden a 186.9 Gg CO2eq y provienen principalmente de la fermentación entérica del ganado, actividad que aporta 169.0 Gg CO2eq, (90.5% de las mismas). Las emisiones de N2O del sector ascienden a 116.9 Gg CO2eq y provienen principalmente de las actividades vinculadas a los suelos agrícolas, siendo las excretas directas del ganado en pasturas la subcategoría que más aporta N2O en la provincia con 81.3 Gg CO2eq y representa el 69.6% de ellas. Por último, las emisiones de CO2 provienen en su totalidad de la aplicación de urea. El inventario de emisiones del Sector Agricultura en la provincia de Cienfuegos constituye una herramienta valiosa para tomar decisiones a nivel local, priorizar acciones y medidas de mitigación acorde a las metas nacionales, apoyar el desarrollo, así como implementar y monitorear el impacto de dichas acciones.

ABSTRACT In this study, a pilot-scale plug flow reactor has been operated at a hydraulic retention time of 30 d with substrate concentration of total solids (7-10 %) under room temperature ranging from 25-38 °C with a working volume of 1.44*10-3 m3 during 186 days. The average chemical oxygen demand (COD) removal was 66.9 % operating at 1.7 kgVS/m3d. Moreover, the alkalinity to total inorganic carbon rated 0.31 being considered a proper value for the operational control of the reactor. In addition, 65.1 % of Total Volatile Solids removal was attained. The specific biogas and methane yields were up to 0.22 m3/kg VS, 0.25 m3/kg VS, respectively. Long-term operation in a pilot scale demonstrated the technological potential and industrial application of cattle manure treatment for biogas production as a circular economy contribution.

RESUMEN En este estudio, se operó un reactor de flujo pistón a escala piloto con un tiempo de retención hidráulica de 30 días con una concentración de sustrato de sólidos totales (7-10 %) a temperatura ambiente que oscilaba entre 25 y 38 °C, con un volumen de trabajo de 1,44 *10-3 m3 durante 186 días. La remoción promedio de la demanda química de oxígeno (DQO) fue del 66,9 % operando a 1,7 kgVS/m3d. Por otro lado, la relación de la alcalinidad con respecto al carbono inorgánico total fue de 0,31, considerándose un valor adecuado para el control operativo del reactor. Además, se alcanzó el 65,1 % de remoción de Sólidos Volátiles Totales. Los rendimientos específicos de biogás y metano fueron de hasta 0,22 m3/kg VS y 0,25 m3/kg VS, respectivamente. La operación a largo plazo a escala piloto demostró el potencial tecnológico y la aplicación industrial del tratamiento del estiércol de ganado para la producción de biogás como contribución a la economía circular.

ABSTRACT Introduction: In Cuba, there is a tendency to decentralize productions with the creation of livestock modules where different livestock species coexist, such as swine, cattle and poultry. In this context, anaerobic digestion (AD) is an alternative for the decarbonization of the agricultural sector, since it generates energy during waste treatment. Objective: To evaluate the AD of swine manure (SM) and poultry manure (PM) with cattle manure (CM) in terms of biochemical methane potential (BMP), and kinetic parameters in mono and co-digestion. Materials and Methods: The trial was conducted in 2 L reactors at 27 °C (average). The BMP of SM, PM and CM was determined in mono-digestion, and then with addition of 15, 30 and 45 % of CM, to the PM40:SM60 mixture. To describe the kinetic behavior of the process, experimental data were fitted to three first and second order models. Results and Discussion: The experimental BMP with CM addition was higher than expected, with increase between 26-31 %, demonstrating the synergy of the mixtures; since the C/N ratio and the methanogenic archaeal community were improved. The models were adjusted to the experimental data with adjusted coefficients of determination higher than 90 %. Conclusions: The addition of CM increased the experimental methane yield over the expected one. The Hill model shows a maximum yield of 369 LCH4/kgVS for mixtures with 15 and 30 % CM. The best variant was with 15 %, and it is necessary to transport manure from 20 cows to the biodigester.

RESUMEN Introducción: En Cuba, existe tendencia a descentralizar producciones con la creación de módulos pecuarios donde coexisten diferentes especies de ganado, como porcino, vacuno y avícola. En este contexto, la digestión anaerobia (DA) resulta una alternativa para la descarbonización del sector agropecuario, ya que genera energía durante el tratamiento de residuales. Objetivo: Evaluar la DA de estiércol porcino (EP) y gallinaza (EG) con estiércol vacuno (EV) en términos del potencial bioquímico de metano (PBM), y parámetros cinéticos en mono y codigestión. Materiales y Métodos: El ensayo se realizó en reactores de 2 L a 27 ºC (promedio). Se determinó el PBM del EP, EG y EV en monodigestión, y luego con adición de 15, 30 y 45 % de EV, a la mezcla EG40:EP60. Para describir el comportamiento cinético del proceso, se ajustaron los datos experimentales a tres modelos de primero y segundo orden. Resultados y Discusión: El PBM experimental con adición de EV fue superior al esperado, con incremento entre 26-31 %, demostrando la sinergia de las mezclas; ya que se mejoró la relación C/N y la comunidad de arqueas metanogénicas. Los modelos se ajustaron a los datos experimentales con coeficientes de determinación ajustado superiores al 90 %. Conclusiones: La adición de EV aumentó el rendimiento de metano experimental respecto al esperado. El modelo de Hill muestra un rendimiento máximo de 369 LCH4/kgSV para las mezclas con 15 y 30 % de EV. La mejor variante fue con 15 %, y se necesita transportar estiércol de 20 vacas al biodigestor.

Resumen Este trabajo analiza la relación de emisiones agrícolas de metano y óxido nitroso en función del producto interno bruto per cápita y su término cuadrático en 26 países latinoamericanos y del Caribe (1990-2019); considera también el stock de inversión extranjera para probar hipótesis del paraíso contaminante, la superficie agrícola (SA) y el metano para la función de óxido nitroso. El estudio comprendió pruebas de raíz unitaria y cointegración. La estimación de coeficientes se realizó por mínimos cuadrados completamente modificados (FMOLS), efectos comunes correlacionados (CCE) y grupo medio aumentado (AMG). Los resultados por FMOLS muestran evidencia de una probable curva ambiental de Kuznets en el conjunto de países para metano, además sustentan un paraíso contaminante. Los resultados por CCE y AMG indican lo contrario. Para óxido nitroso los resultados de FMOLS apoyan una curva en U. Lo anterior sostiene una política ambiental conjunta de ambos gases, donde la SA es un elemento clave. Los resultados anteriores se tienen que corroborar con otros métodos y extender los estudios a otros países en el tiempo.

Abstract This paper aims to analyze the relationship between agricultural methane and nitrous oxide emissions as a function of per capita gross domestic product (GDP) and its quadratic term in 26 Latin American and Caribbean countries (1990-2019). It also considers the stock of foreign investment to test the polluting paradise hypothesis, agricultural land (AL), and, additionally, methane for nitrous function. The study comprised unit root and cointegration tests. Coefficients were estimated using fully modified least squares (FMOLS), correlated common effects (CCE), and augmented mean group (AMG). Results by FMOLS show statistical evidence of an environmental Kuznets curve in the set of countries for methane and support the polluting paradise hypothesis. However, results from CCE and AMG show the opposite. For nitrous oxide, FMOLS support a U-shaped curve. The above supports a joint environmental policy for both gases, where al is a key element. The previous results must be corroborated with other methods and the studies extended to other countries over time.

Resumen El objetivo fue evaluar el uso creciente de aceite de ajo, ajonjolí y canela en la producción de CH4 in vitro de pasto llanero con 60 días de rebrote. Se evaluó la adición de 0, 2.5, 5.0, 7.5 y 10 % de aceite de ajo, canela o ajonjolí en una fermentación in vitro usando como sustrato pasto llanero con 60 días de rebrote. Las variables evaluadas fueron producción acumulada de CH4 a las 12, 24, 36, 48 y 72 h, degradación de materia seca (DMS) y los estimadores de cinética de producción de CH4 (A= potencial de producción de CH4, b= tasa constante de producción de CH4 y k= tiempo lag). La producción de CH4 y DMS se analizaron con un diseño experimental completamente al azar y contraste ortogonal. Los estimadores fueron un análisis descriptivo. El aumento de aceite de ajo y canela redujo linealmente la producción de CH4 a las 12, 24, 36, 48 y 72 h. La DMS disminuyó linealmente con cualquiera de los tres aceites (P<0.05). El mayor valor de A fue con 2.5 % de aceite de ajo, el mayor valor de k y b fue con 10 % de aceite de canela. En conclusión, el uso de aceites de ajo y canela mostraron una disminución lineal de la producción de CH4 y DMS de pasto llanero en condiciones in vitro.

Abstract The objective was to evaluate the increasing use of garlic, sesame, and cinnamon oil in the production of CH4 in 60 d in vitro regrowth of Koronivia grass. The addition of 0, 2.5, 5.0, 5.0, 7.5, and 10 % garlic, cinnamon, or sesame oil was evaluated in an in vitro fermentation using a 60-d regrowth of Koronivia grass as substrate. The variables evaluated were cumulative CH4 production at 12, 24, 36, 36, 48, and 72 h; dry matter degradation (DMD), and CH4 production kinetics estimators (A= CH4 production potential, b= CH4 production rate constant, and k= lag time). The CH4 production and the DMD were analyzed with a completely randomized experimental design and orthogonal contrast. The estimators were subjected to a descriptive analysis. An increase of garlic oil and cinnamon linearly reduced CH4 production at 12, 24, 36, 48, and 72 h. The DMD decreased linearly with the use of any of the three oils (P<0.05). The highest value of A was obtained with 2.5 % garlic oil, and the highest value of k and b, with 10 % cinnamon oil. In conclusion, the use of garlic and cinnamon oils resulted in a linear decrease of Koronivia grass CH4 and Koronivia grass DMD under in vitro conditions.

RESUMEN Las características químicas del pasto Cenchrus clandestinus, base alimenticia en los sistemas de producción lechera, hacen necesaria la suplementación energética. El grano de maíz es el alimento más empleado para este propósito, pero dada su demanda y precio, el objetivo de este trabajo fue evaluar su reemplazo parcial por otras fuentes de carbohidratos no fibrosos sobre la emisión de metano, el balance energético-nitrogenado y el desempeño productivo de vacas lecheras. Dieciséis vacas Holstein recibieron Cenchrus clandestinus y uno de cuatro concentrados formulados con maíz (Zea mays) y sorgo (Sorghum vulgare), yuca (Manihot esculenta) o pulpa cítrica (Citrus sp) en reemplazo parcial del maíz. La inclusión de estos ingredientes no alteró el consumo de materia seca ni su digestibilidad, producción de metano, balance energético-nitrogenado, producción de leche o su composición. Los resultados permiten concluir que esos ingredientes pueden reemplazar parcialmente al maíz en la dieta de vacas lecheras.

ABSTRACT The chemical characteristics of Cenchrus clandestinus grass, nutritional base in dairy production systems, demand the energy supplementation. Corn grain is the most used food for this purpose, but considering its demand and prices, the aim of this study was to evaluate its partial replacement by alternative non-fibrous carbohydrates sources on methane emissions, energy and nitrogen balance and productive performance of dairy cows. Sixteen multiparous Holstein cows were fed Cenchrus clandestinus plus one of four concentrate supplements formulated with corn (Zea mays) or a partial replacement of corn with sorghum (Sorghum vulgare), cassava (Manihot esculenta) or citrus pulp (Citrus sp). Inclusion of these ingredients did not affect dry matter intake, dry matter digestibility, enteric methane emissions, energy and nitrogen balance, milk yield or composition. The results allow to conclude that these ingredients can partially replace corn in the diet of lactating dairy cows.