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The COVID-19 pandemic has exacerbated the difficulties associated with the need to transition the cattle sector in Latin America towards achieving sustainability and created a “double crisis” of pandemic and climate change. The increasing demand for animal sourced foods and the need to address the negative environmental impacts of cattle production, including greenhouse gas emissions, biodiversity loss and deforestation, and the implications of climate change on cattle production (prolonged droughts, prolonged rainy seasons, heat stress), have placed strong emphasis on sustainable intensification of forage-based beef and dairy systems for climate change mitigation and adaptation. This is needed to meet the commitments made by many Latin American countries to reduce greenhouse gas emissions under the Paris Agreement. Through a qualitative approach, this perspective paper reviews the present and potential impacts of the COVID-19 pandemic on progress towards sustainable intensification of the Colombian cattle sector. It also outlines new opportunities for sustainable intensification in Colombia that may provide useful examples for other Latin American countries. Short-term impacts such as: (i) increased input prices, (ii) limited access to inputs, credit, and technical assistance, and (iii) reduced incomes, have limited investment in sustainable intensification along the value chains. Reduced resources for research and development funding, unavailability of skilled and experienced staff, restrictions to travel and person-to-person interactions, in tandem, have caused setbacks in the development and application of sustainable technologies and programs. This has been addressed by increased use of technology for communication but there are difficulties with the broad availability of such technologies, especially farmers. A long-term shift of consumer demand towards more sustainable animal products is occurring and expected to continue, and this should lead to new opportunities for sustainable intensification.

Con el objetivo de evaluar los efectos de los sistemas de cultivo-arboles- pastos sobre el rendimiento de maíz y frijol, y la calidad de suelo, en la micro cuenca Tecomapa, fueron establecidas cinco parcelas experimentales: quema tradicional (Q); sistema agroforestal Quesungual (SAQ); bosque secundario (Bs); potreros mejorados con Brachiaria sp - Marandú, (Pm); y sistema silvopastoril (SSP). En las cuales, dos sub parcelas localizadas en la parte alta y baja del relieve fueron establecidas para evaluar calidad de suelo y la erosión laminar, en 2011, 2012 y 2013. Como resultado, la tasa de erosión fuera de la parcela, únicamente ocurrió en el sistema de quema (Q) con 28.3 t ha-1 a-1. La tasa de erosión dentro de la parcela fue moderada 31.98 y 42.97 t ha-1 a-1, en los sistemas BS y Pm, y alta 62.97 y 121.79 t ha-1 a-1, en los sistemas SAQ y SSP. La calidad de los suelos fue infl uenciada por los contenidos de materia orgánica en el suelo (MOS) mayores a 4000 kg ha-1 en los sistemas SAQ, SSP y Bs. Este indicador fue correlacionado negativamente con el incremento de arcilla en el horizonte superfi cial de los suelos con pastura. Finalmente, los indicadores de calidad de suelo asociados al rendimiento del cultivo de maíz y frijol fueron el espesor orgánico de suelo, las tasas de infi ltraciones rápidas, y la erosión de suelos.

Forage-based livestock production plays a key role in national and regional economies, for food security and poverty alleviation, but is considered a major contributor to agricultural GHG emissions. While demand for livestock products is predicted to increase, there is political and societal pressure both to reduce environmental impacts and to convert some of the pasture area to alternative uses, such as crop production and environmental conservation. Thus, it is essential to develop approaches for sustainable intensification of livestock systems to mitigate GHG emissions, addressing biophysical, socio-economic and policy challenges. This paper highlights the potential of improved tropical forages, linked with policy incentives, to enhance livestock production, while reducing its environmental footprint. Emphasis is on crop-livestock systems. We give examples for sustainable intensification to mitigate GHG emissions, based on improved forages in Brazil and Colombia, and suggest future perspectives.

Las sociedades prehispánicas de las zonas bajas Mayas fueron afectadas en repetidas ocasiones por la caída de ceniza de las erupciones del Volcán El Chichón, Chiapas, México. Los horizontes de tefra del Holoceno Tardío se preservaron en los sedimentos deltaicos del Río Usumacinta-Grijalva, aproximadamente 150 km al NNE del volcán. Un núcleo de sedimentos del delta que cubre los últimos 2100 años, fue examinado para tefra, polen, polimorfos y macrofósiles. Se utilizaron la tefracronología y palinología para reconstruir la temporalidad, magnitud, e impacto de las erupciones pasadas. Siete de los diez horizontes de tephra reconocidos se relacionaron a las erupciones pasadas del Volcán El Chichón y muestran el fuerte impacto de las erupciones. Una gran erupción ocurrida alrededor de A.D. 539 produjo un efecto dramático en el núcleo del área de la civilización Maya y posiblemente fue la causa del Hiatus Maya y del desplazamiento demográfico hacia el Delta del Usumacinta-Grijalva. Esta erupción también parece haber provocado cambios ambientales repentinos a nivel mundial. doi: https://doi.org/10.22201/igeof.00167169p.2009.48.1.102

Pre-Columbian societies in the Maya Lowlands were repeatedly exposed to tephra-fall from past eruptions of El Chichón volcano, Chiapas, Mexico. Late Holocene tephra layers are well preserved in sediments of the Usumacinta-Grijalva river delta, about 150 km NNE of the volcano. A sediment core from the delta spans the last 2100 years, and was examined for tephra, pollen, palynomorphs and macrofossils. We used tephrochronology and palynology to reconstruct the timing, magnitude and impact of past eruptions. Seven of the ten recognised tephra layers are related to past eruptions of El Chichón volcano and show remarkable impacts of the eruptions. A large eruption around A. D. 539 had a dramatic effect on the core area of Maya civilisation and was probably responsible for the onset of the Maya Hiatus and a demographic shift towards the Usumacinta-Grijalva delta. The eruption also seems to have caused rapid environmental changes worldwide.

As global demand for livestock products (such as meat, milk and eggs) is expected to double by 2050, necessary increases to future production must be reconciled with negative environmental impacts that livestock cause. This paper describes the LivestockPlus concept and demonstrates how the sowing of improved forages can lead to the sustainable intensification of mixed crop-forage-livestock-tree systems in the tropics by producing multiple social, economic and environmental benefits. Sustainable intensification not only improves the productivity of tropical forage-based systems but also reduces the ecological footprint of livestock production and generates a diversity of ecosystem services (ES) such as improved soil quality and reduced erosion, sedimentation and greenhouse gas (GHG) emissions. Integrating improved grass and legume forages into mixed production systems (crop-livestock, tree-livestock, crop-tree-livestock) can restore degraded lands and enhance system resilience to drought and waterlogging associated with climate change. When properly managed tropical forages accumulate large amounts of carbon in soil, fix atmospheric nitrogen (legumes), inhibit nitrification in soil and reduce nitrous oxide emissions (grasses), and reduce GHG emissions per unit livestock product. The LivestockPlus concept is defined as the sustainable intensification of forage-based systems, which is based on 3 interrelated intensification processes: genetic intensification - the development and use of superior grass and legume cultivars for increased livestock productivity; ecological intensification - the development and application of improved farm and natural resource management practices; and socio-economic intensification - the improvement of local and national institutions and policies, which enable refinements of technologies and support their enduring use. Increases in livestock productivity will require coordinated efforts to develop supportive government, non-government organization and private sector policies that foster investments and fair market compensation for both the products and ES provided. Effective research-for-development efforts that promote agricultural and environmental benefits of forage-based systems can contribute towards implemention of LivestockPlus across a variety of geographic, political and socio-economic contexts.Keywords: Eco-efficiency, environmental benefits, livestock and environment, mixed farming, pastures, smallholders.DOI: 10.17138/TGFT(3)59-82

An inter-institutional and multi-disciplinary project to identify Brachiaria genotypes, which combine waterlogging tolerance with high forage yield and quality, for use in agricultural land in Latin America with poor drainage, is underway. The aim is to improve meat and milk production and mitigate the impacts of climate change in the humid areas of Latin America. Researchers at the International Center for Tropical Agriculture (CIAT) have developed a screening method to evaluate waterlogging in grasses. Using this method, 71 promising hybrids derived from the species, Brachiaria ruziziensis, B. brizantha and B. decumbens, were evaluated. Four hybrids with superior waterlogging tolerance were identified. Their superiority was based on greater: green-leaf biomass production, proportion of green leaf to total leaf biomass, green-leaf area, leaf chlorophyll content and photosynthetic efficiency; and reduced dead-leaf biomass. These hybrids, together with previously selected hybrids and germplasm accessions, are being field-tested for waterlogging tolerance in collaboration with National Agricultural Research Institutions and farmers from Colombia, Nicaragua and Panama.

Se da a conocer una nueva sección que incluye nueve yacimientos de microvertebrados en superposición estratigráfica en la Cuenca de Calatayud-Montalbán (España). Se describen las localidades de la sección de la Cañada y sus faunas de micromamíferos, lo que posibilita su correlación con el Vallesiense inferior de la cercana sección de Nombrevilla. Los resultados obtenidos en este trabajo son importantes debido a que ayudan a mejorar la resolución temporal del registro faunístico del Vallesiense inferior del área de Daroca, y a precisar su posición bioestratigráfica relativa. Por otra parte, el tramo superior de la sección de la Cañada incluye dos faunas del Turoliense que incrementan el escaso conocimiento del registro de esta edad en la Cuenca de Calatayud-Montalbán.

Se describen los micromamíferos del Mioceno medio (Aragoniense medio) de La Retama, sector centro-oriental español. La fauna de roedores es relativamente pobre y está compuesta únicamente por diez especies. Sin embargo, cabe destacar la elevada diversidad de los quirópteros, representados por cinco géneros. Se describe también dos taxa de insectívoros. Esta asociación fósil ha sido correlacionada con la zona Db (MN5). La reconstrucción paleoambiental de La Retama inferida a partir de la fauna de micromamíferos corresponde a un ambiente abierto y seco.