¿Es una sabana nativa un sumidero de carbono? ¿Y cuáles son los cambios que se generan al convertirse en un pastizal?

Como parte de los cambios de uso del suelo en las tierras bajas del Orinoco, las sabanas han sido reemplazadas por Brachiaria. La pregunta que sigue sin respuesta es:¿cómo la sustitución de la vegetación nativa afecta el intercambio de CO2 en las escalas estacionales y anuales? Para evaluarlos intercambios de carbono, hemos determinado los flujos de CO2 por el método Eddy,y los flujos de CO2 del suelo. La dinámica fuente/sumidero del carbono en los dos doseles difiere notablemente. Mediciones anuales de la producción neta del ecosistema indican que Brachiaria constituyó un sumidero de carbono de 216gCm-2 año-1 Por el contrario,la sabana presentó un estado equilibrado de carbono(36 gCm-2 año-1). La respiración estacional del ecosistema estuvo linealmente relacionada con la producción estacional primaria bruta enuna proporción de 53%.La captación de carbono fue limitada por el contenido volumétrico de agua en el suelo como se reflejó en la eficiencia del uso del agua.After land use changes in the Orinoco lowlands, savannas have been replaced by Brachiaria pasture. Question that remain unanswered include: how do the replacement of the native vegetation affect the exchange of CO2 on the seasonal and annual course.To address the inquires, we determined the CO2 fluxes by eddy covariance and soil CO2 efflux system. The carbon source/sink dynamics over the two canopies differed markedly. Annual measurements of the Net Ecosystem Production indicated that the Brachiaria field was a carbon sink of 216 g C m- 2 y-1. However, this carbon accumulation by the ecosystem is trading for water losses. By contrast, the savanna stand presented a balanced carbon status (36 g C m-2 y-1).Seasonal ecosystem respiration was linearly related to seasonal gross primary production and the proportion of 53 percent. Carbon uptake was limited for the volumetric soil water content as reflected by the water use efficiency.Eje A4: Ambiente, Naturaleza y AgroecologíaFacultad de Ciencias Agrarias y Forestale

¿Es una sabana nativa un sumidero de carbono? ¿Y cuáles son los cambios que se generan al convertirse en un pastizal?

Como parte de los cambios de uso del suelo en las tierras bajas del Orinoco, las sabanas han sido reemplazadas por Brachiaria. La pregunta que sigue sin respuesta es:¿cómo la sustitución de la vegetación nativa afecta el intercambio de CO2 en las escalas estacionales y anuales? Para evaluarlos intercambios de carbono, hemos determinado los flujos de CO2 por el método Eddy,y los flujos de CO2 del suelo. La dinámica fuente/sumidero del carbono en los dos doseles difiere notablemente. Mediciones anuales de la producción neta del ecosistema indican que Brachiaria constituyó un sumidero de carbono de 216gCm-2 año-1 Por el contrario,la sabana presentó un estado equilibrado de carbono(36 gCm-2 año-1). La respiración estacional del ecosistema estuvo linealmente relacionada con la producción estacional primaria bruta enuna proporción de 53%.La captación de carbono fue limitada por el contenido volumétrico de agua en el suelo como se reflejó en la eficiencia del uso del agua.After land use changes in the Orinoco lowlands, savannas have been replaced by Brachiaria pasture. Question that remain unanswered include: how do the replacement of the native vegetation affect the exchange of CO2 on the seasonal and annual course.To address the inquires, we determined the CO2 fluxes by eddy covariance and soil CO2 efflux system. The carbon source/sink dynamics over the two canopies differed markedly. Annual measurements of the Net Ecosystem Production indicated that the Brachiaria field was a carbon sink of 216 g C m- 2 y-1. However, this carbon accumulation by the ecosystem is trading for water losses. By contrast, the savanna stand presented a balanced carbon status (36 g C m-2 y-1).Seasonal ecosystem respiration was linearly related to seasonal gross primary production and the proportion of 53 percent. Carbon uptake was limited for the volumetric soil water content as reflected by the water use efficiency.Eje A4: Ambiente, Naturaleza y AgroecologíaFacultad de Ciencias Agrarias y Forestale

Jersey cattle in Africa: From the Breed's Documented Past to a Profit Index-Linked Future

The aim of this paper was to review the documented reports of the Jersey breed in Africa; and the suitability of the breed for a dairy profit index relevant for the future of Rwanda's dairy development programmes. We extended our review of available reports on the Jersey breed to various African countries to deliver on our main objective of providing relevant knowledge to support long term genetic improvement plans that could be customised to any targeted countries based on the productions systems, constraints, national policies and the local socioeconomic development targets. Through extensive research the authors have confirmed a presence for the Jersey breed across the majority of the continent of Africa, whether current or historic, as a pure breed or used in cross breeding programmes

COVID-19 in sub-Saharan Africa: impacts on vulnerable populations and sustaining home-grown solutions

© 2020, The Canadian Public Health Association. This commentary draws on sub-Saharan African health researchers’ accounts of their countries’ responses to control the spread of COVID-19, including social and health impacts, home-grown solutions, and gaps in knowledge. Limited human and material resources for infection control and lack of understanding or appreciation by the government of the realities of vulnerable populations have contributed to failed interventions to curb transmission, and further deepened inequalities. Some governments have adapted or limited lockdowns due to the negative impacts on livelihoods and taken specific measures to minimize the impact on the most vulnerable citizens. However, these measures may not reach the majority of the poor. Yet, African countries’ responses to COVID-19 have also included a range of innovations, including diversification of local businesses to produce personal protective equipment, disinfectants, test kits, etc., which may expand domestic manufacturing capabilities and deepen self-reliance. African and high-income governments, donors, non-governmental organizations, and businesses should work to strengthen existing health system capacity and back African-led business. Social scientific understandings of public perceptions, their interactions with COVID-19 control measures, and studies on promising clinical interventions are needed. However, a decolonizing response to COVID-19 must include explicit and meaningful commitments to sharing the power—the authority and resources—to study and endorse solutions