Abstract
A large area of the terrestrial land surface is used for livestock grazing. Trees on grazing lands provide and can enhance multiple ecosystem services such as provisioning, cultural and ...regulating, that include carbon sequestration. In this study, we assessed the above- and belowground carbon stocks across six different land-uses in livestock-dominated landscapes of Mexico. We measured tree biomass and soil organic carbon (SOC) stocks in fodder banks, live fences, pasturelands with dispersed trees, secondary forests, and primary forests from three different geographical regions and compared them with conventional open pasturelands respectively. We also calculated tree diversity indices for each land-use and their similarity with native primary forests. The aboveground woody biomass stocks differed significantly between land-uses and followed the gradient from less diverse conventional open pasturelands to silvopastoral systems and ecologically complex primary forests. The SOC stocks showed a differential response to the land-use gradient dependent on the study region. Multivariate analyses showed that woody biomass, fine root biomass, and SOC concentrations were positively related, while land-use history and soil bulk density showed an inverse relationship to these variables. Silvopastoral systems and forest remnants stored 27–163% more carbon compared to open pasturelands. Our results demonstrate the importance of promoting appropriate silvopastoral systems and conserving forest remnants within livestock-dominated landscapes as a land-based carbon mitigation strategy. Furthermore, our findings also have important implications to help better manage livestock-dominated landscapes and minimize pressures on natural protected areas and biodiversity in the hotspots of deforestation for grassland expansion.
Backyards are family settings adjacent to the house, characterized mainly by being small-scale and diversified productive spaces. The research typologically characterized the backyards and their ...contribution to family food security in La Concordia municipality, Chiapas, Mexico. The research was descriptive and mixed, quantitative, and qualitative, and semi-structured interviews were applied to 130 families. For the typification, 21 variables were used, and the statistical techniques of Factorial Analysis and Clusters were applied. The cases studied were classified, according to the relevance of their production and contribution to food security, into two general groups: a) a group of backyards that is more productive and contributes to food security, which in turn includes three subtypes of backyards that differ from each other by their profile towards vegetable or poultry production for subsistence, and/or pigs as a form of savings; b) a group of less productive backyards in which other management strategies for food security are assumed and differ from each other by the level of expulsion of labor force and types of families, nuclear or extended. Poultry and plant species for multiple uses was the most frequently characteristic, regardless of the type of backyard.
RESUMO: Os quintais são ambientes familiares adjacentes à casa, caracterizados principalmente por serem espaços produtivos de pequena escala e diversificados. A pesquisa teve como objetivo caracterizar tipologicamente os quintais e sua contribuição para a segurança alimentar familiar no município de La Concordia, Chiapas, México. A pesquisa foi descritiva e mista, quantitativa e qualitativa, na qual foram aplicadas entrevistas semiestruturadas a 130 famílias. Para a tipificação foram utilizadas 21 variáveis e aplicadas as técnicas estatísticas de Análise Fatorial e Clusters. Os casos estudados foram classificados, de acordo com a relevância de sua produção e contribuição para a segurança alimentar, em dois grupos gerais: a) um grupo de quintais mais produtivos e que contribuem para a segurança alimentar, que por sua vez inclui três subtipos de quintais que diferem entre si pelo seu perfil para a produção de hortaliças ou aves para subsistência, e/ou suínos como forma de poupança; b) conjunto de quintais menos produtivos em que se assumem outras estratégias de gestão da segurança alimentar e diferem entre si pelo nível de expulsão de mão de obra e tipos de famílias, nucleares ou extensas. Aves e espécies vegetais de uso múltiplo foi a característica mais encontrada, independente do tipo de quintal.
Fire has been an integral part of ecosystem functioning in many biomes for a long time, but the increased intensity and frequency of wildfires often affect plant diversity and carbon storage. ...Prescribed burning is one of the alternatives to forest fuel management where the fire is controlled and carried out under a determined set of weather conditions and objectives. The effect of prescribed burning on plant diversity and carbon (C) storage has not been studied widely. The objective of this study was to evaluate the effect of prescribed burning on plant diversity indices, biomass stocks, and soil C storage in the tropical highland forests of Southern Mexico. We assessed plant diversity and carbon stocks at 21 sampling sites: seven with prescribed burning, seven non-burning, and seven with wildfires. We calculated tree biodiversity indices, stand structural properties, and species composition among burning treatments. We quantified C stocks in vegetation biomass by using an allometric equation and forest litter by direct sampling. We analyzed 252 soil samples for soil organic C content and other properties. The results showed that the biodiversity index was higher in sites with prescribed burning (Shannon index, H = 1.26) and non-burning (H = 1.14) than in wildfire sites (H = 0.36). There was a greater similarity in plant species composition between non-burning and prescribed burning sites compared to wildfire sites. Prescribed burning showed a positive effect on soil carbon storage (183.9 Mg C ha−1) when compared to wildfire (144.3 Mg C ha−1), but the difference was not statistically significant (p > 0.05) in biomass stocks. Prescribed burning in this study conserved plant diversity as well as soil carbon stocks compared to non-burning, the opposite of what we found in wildfires.
The sustainability of family farms, or Family Production Units (FPUs), cultivating native maize varieties in Chiapas, Mexico, is intricately linked to economic, socio-productive, environmental, and ...cultural factors. Given their significance within the regional socio-productive framework, the objective of this study was to assess sustainability across environmental, social, and economic dimensions. The methodology employed for sustainability analysis was the Framework for Evaluation of Natural Resource Management Systems (MESMIS). Thirty FPUs were purposively selected from 14 communities spanning four municipalities and were typologically classified into three groups: Traditional, Maize Growers-Livestockers, and Diversified. In-depth interviews were conducted with individual farmers, complemented by group interviews involving entire families. The collected data underwent processing through multiple correspondence statistical analysis, analysis of variance for linear models, and multiple comparisons of means. The results indicated that the Diversified FPU group exhibited higher sustainability, covering 68% of the sustainability perimeter. Consequently, this group demonstrated better conditions for preserving native maize varieties over time and developing strategies to meet their needs concurrently. The Traditional FPU group covered 58%, while the Maize Growers-Livestockers group covered 52% of the sustainability perimeter. In conclusion, it was observed that family reproduction strategies, grounded in resource utilization (capitals), shape forms of nature appropriation that are continually reconfigured. These configurations play a pivotal role in defining the sustainability of FPUs engaged in native maize cultivation in the Frailesca region.
Seeds of Raphanus sativus L. var. Champion were inoculated with commercial strains of rhizospheric fungi+bacteria. A completely randomized experiment was designed with four treatments: ...Chromobacterium violaceum+Acinetobacter calcoaceticus (BiofosfoBuap®, T1), Azospirillum brasilense (AzoFer), Glomus intraradices (MicorrizaFer), and uninoculated control. Each treatment had 20 replicates. The objective was to evaluate the effect of the different treatments on leaf growth, taproot length and dry weight, dry weight of leaves and tubers, and fresh tuber weight. Net assimilation rate (NAR), absolute growth rate (AGR), and relative growth rate (RGR) were calculated. Thirty three days after sowing (das), plants inoculated with C. violaceum+A. calcoaceticus had 52.67% more leaf area than the control, and 42 das they had 72.30% more leaf area. Thirty three das, treatments with C. violaceum+A. calcoaceticus and A. brasilense had 49.66% and 45.52% more dry leaf weight than the control. Fresh weight of tubers for the same two treatments was 65.03% and 63.11% higher than the control 33 das, respectively, and 80.70% and 74.56% higher 42 das. Co-inoculation with C. violaceum+A. calcoaceticus and inoculation with A. brasilense alone promoted growth of radish tubers as a consequence of increased leaf area and biomass as well as an increase in net assimilation rate. Highlights The effect of rhizosphere bacteria and fungi on the leaf area of radish plants depends more on the leaves size than on the leaves number produced by the plant. The better growth observed in plants inoculated with C. violaceum + A. calcoaceticus and A. brasilense might depend on the greater plant hormone synthesis. The effects of C. violaceum + A. calcoaceticus on plant growth are better than a single microorganism inoculation and such effects depend on the enhanced co-inoculation. Inoculating plants with C. violaceum + A. calcoaceticus promotes the tuber biomass increase over the taproot growth. Inoculation with C. violaceum + A. calcoaceticus induces transfer of photosynthates from above ground part of the plant to the tuber in order to produce biomass. Inoculation with C. violaceum + A. calcoaceticus favored accumulation of biomass in leaves and tubers, resulting in total plant biomass production, although not taproot length.
Las Unidades de Producción Familiar (UPF) están conformadas por capitales natural, físico, financiero, humano y social. Los dos últimos constituyen la base del funcionamiento del resto y de la unidad ...de producción. En México, Chiapas y la Frailesca, la producción de maíces, particularmente de maíces locales, tiene valor cultural, agronómico y económico. El objetivo de esta investigación fue caracterizar las Unidades de Producción Familiar que cultivan maíces locales en la región Frailesca del estado de Chiapas, sobre la base cultural del manejo de los capitales humano y social. Se estudiaron 80 UPF de 20 comunidades seleccionadas mediante un muestreo por redes. Se utilizó el enfoque Modos de Vida Sustentable como marco de referencia. Se aplicaron entrevistas semiestructuradas y se realizaron observaciones participantes. En el estudio predominaron las familias nucleares con líderes de edad avanzada. Los jóvenes no priorizan la conservación de los maíces locales sino actividades más rentables como la ganadería, los maíces híbridos y el café. Existe un excesivo uso de agroquímicos que afecta los recursos suelo, agua y biodiversidad. Se distinguieron 6 tipos de UPF de acuerdo con sus capitales humano y social. El grupo 3 (G3) mostró un mejor equilibrio entre ambos por la participación familiar, destacándose entre los de mayor experiencia en el cultivo de maíces locales y por tener relaciones locales y de cooperación más sólidas. Se concluye que las UPF presentan características que contribuyen o afectan la conservación de los maíces locales, como la continuidad generacional, el deterioro de los recursos naturales que sostienen el cultivo a través de la fusión de las prácticas tradicionales con las modernas y la dependencia de recursos externos.
Con el objetivo de caracterizar el suelo del agroecosistema maíz con los sistemas de producción convencional, agroecológico y mixto, para documentar e identificar estrategias que consideren los ...aspectos ambientales, sociales y económicos que conlleven a alternativas para la producción sostenible, se estudiaron las propiedades físico-químicas y biológicas de 35 muestras obtenidas en 28 ejidos de la región Frailesca, interpretadas con la Norma Oficial Mexicana NOM-021-RECNAT-2000. Los resultados indican una acidez generalizada para los tres sistemas con un pH de 5.05, 5.25 y 5.24, la capacidad intercambio catiónico es baja (13.96, 12.54, y 14.95 cmol(+) kg‑1) y niveles medios de materia orgánica (3.5, 2.58 y 3.45%). Así mismo, los macronutrientes, como el fósforo se encuentra en niveles altos (75.36, 74.78 y 45.05 mg kg‑1) y el potasio se encontró en niveles bajos (3.86, 3.12 y 2.66 mg kg‑1) y los micronutrientes se encuentran en niveles medios como el hierro (3.24, 2.03 y 2.62 mg kg‑1) y boro (1.58, 1.06 y 1.37 mg kg-1). Para el caso de la textura del suelo presentan suelos franco-arcillo-arenoso y franco-arenoso. Desde el punto de vista de las características biológicas del suelo, la macrofauna con el sistema agroecológico reportó mayor diversidad de seres vivos de acuerdo al índice de Shannon y Weaver (H’ = 1.121), destacan coleópteros, anélidos, himenópteros, isópteros y gasterópodos. En ese mismo sentido, para el caso de microorganismos sobresale en diversidad de microorganismos (H’ = 1.121) reportando entomopatógenos (Beauveria bassiana y Metarhizium anisopliae), fijadores de nitrógeno (Rhizobium, Azotobacter y Azospirillum) y hongos patógenos como Rizhoctonia, Fusarium y Alternaria y el sistema con menor diversidad fue el convencional con H’ = 0.789. Bajo estas condiciones el suelo, es necesario una estrategia que permita aumentar la calidad y las prácticas de agricultura puedan ser sostenibles.
Introducción: La frecuencia de infarto agudo de miocardio sin elevación del segmento ST se está incrementando y, con ella, los resultados adversos en pacientes con enfermedad coronaria isquémica ...aguda. Objetivo: Identificar las variables electrocardiográficas asociadas a la aparición de eventos cardiovasculares adversos en el infarto agudo de miocardio sin elevación del segmento ST. Método: Se realizó un estudio transversal, de tipo correlacional, con 68 pacientes con infarto agudo de miocardio sin elevación del segmento ST atendidos en el Hospital “Arnaldo Milián Castro”, en la provincia de Villa Clara. Se estudiaron los hallazgos electrocardiográficos y eventos cardiacos adversos durante el ingreso. Se hicieron análisis bivariados para establecer la relación de ambas variables, utilizando el estadígrafo chi cuadrado y el riesgo relativo. Resultados: Los hallazgos electrocardiográficos más frecuentes fueron la inversión de la onda T (≥ 2mm), depresión del segmento ST y el QT corregido largo mediante la fórmula de Bazzet. El 26,5 % presentaron eventos cardiovasculares adversos. La depresión del segmento ST, el QT largo corregido y la elevación del segmento ST en aVR se asociaron significativamente con eventos adversos intrahospitalarios (p < 0,05). Conclusiones: La asociación de la depresión del segmento ST, la elevación del segmento ST en aVR y el QT largo corregido con la ocurrencia de eventos cardiovasculares adversos intrahospitalarios, sugiere que estos hallazgos se pueden tener en cuenta como posibles indicadores de evolución desfavorable en pacientes con infarto agudo de miocardio sin elevación del segmento ST.
Contexto: A partir de un análisis desarrollo de la tecnología en biodigestores, se observó un problema recurrente en la cuantificación rigurosa del metano. mediante una revisión bibliográfica reveló ...sistemas poco eficientes o de costos elevados. Este proyecto plantea un sistema accesible y eficaz que busca contribuir a proyectos académicos y de investigación afines.
Método: La cuantificación de metano se realiza mediante un sensor de la serie MQ-4 acoplado a una cápsula, creando un medio parcialmente cerrado en el que se inyecta, por medio de una jeringa, una dilución de gases de muestra de metano con aire del ambiente, lo cual amplía el rango de medición del sensor.
Resultados: Se elaboró una curva de calibración, ampliando el rango de medición de 0,02-1 % de concentración a 10-80 %v/v, con una varianza de ± 5 %.
Conclusiones: Se desarrolló un prototipo de cuantificación de metano eficiente y accesible para uso académico y de investigación. Esto se complementa con una guía para replicar el proceso.
El objetivo fue evaluar modelos predictivos de la producción metano de los frutos Leucaena collinsii y Guazuma ulmifolia medido a través de la técnica de producción de gas in vitro (TPG) y ...cromatografía de gases. A los frutos se realizó un análisis químico, parámetros de fermentación in vitro, y se estimó metano por cromatografía de gases y por la TPG. Se realizó un análisis de varianza considerando los efectos fijos de la técnica de medición y el tipo de fruto. Se hizo un análisis de correlación y regresión para conocer las ecuaciones y los coeficientes de determinación entre CH4 por cromatografía de gases y estimación de CH4 a partir de la TPG. Se encontró una tendencia positiva entre la estimación de metano por cromatografía de gases y por la TPG, por lo que, la TPG es promisoria para la determinación de metano de frutos de Leucaena collinsii y Guazuma ulmifolia.
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