A comprehensive case study on the sustainability of tropical dairy cattle farming in Oaxaca, Mexico / Um estudo de caso abrangente sobre a sustentabilidade da pecuária leiteira tropical em Oaxaca, México

Tropical dairy cattle farming is one the most relevant economic activities for food production; although, currently faces increasing scrutiny from society due to its potential harm to natural resources and the environment. Moreover, some factors are paramount for the evaluation of the sustainability and productive potential of any given tropical dairy farm: soil quality, profitability, and energy efficiency. This study carried out a sustainability analysis in four types of tropical dairy cattle ranches, through three key indicators (economic profitability, energy efficiency and soil quality) and with a comprehensive approach in the Costa region of Oaxaca, Mexico. Therefore, four farms of different sizes (i.e., small, medium, large, and very large) were selected in Costa de Oaxaca, Mexico. The data collection was carried out for daily milk production, the dynamics of farm inputs (introduction or removal) from the production system, alongside with collection of soil samples. The agroecosystems evaluated were economically profitable, and those with greater intensification of their pasture areas display higher profit margins and energy efficiency. In terms of soil quality, there is a regular potential for its rational utilization.

A pecuária leiteira tropical é uma das atividades econômicas mais relevantes para a produção de alimentos, embora atualmente enfrente crescente discussão da sociedade devido ao seu potencial dano aos recursos naturais e ao meio ambiente. Além disso, alguns fatores são primordiais para a avaliação da sustentabilidade e potencial produtivo de qualquer popriedade leiteira tropical: qualidade do solo, rentabilidade e eficiência energética. O objetivo deste estudo foi realizar uma análise de sustentabilidade em quatro tipos de propriedades de gado leiteiro tropical, por meio de três indicadores chave (rentabilidade econômica, eficiência energética e qualidade do solo) e com uma abordagem abrangente na região da Costa de Oaxaca, México. Portanto, quarto propriedades de diferentes tamanhos (isto é, pequenas, médias, grandes e muito grandes) foram selecionadas na Costa de Oaxaca, México. A coleta de dados foi realizada para a produção diária de leite, a dinâmica dos insumos da fazenda (introdução ou retirada) do sistema de produção, juntamente com coleta de amostras de solo. Os agroecossistemas avaliados foram economicamente rentáveis, sendo que aqueles com maior intensificação de suas áreas de pastagens apresentam maiores margens de lucro e eficiência energética. Em termos de qualidade do solo, existe um potencial regular para a sua utilização racional.

Screening and identification of horticultural soil fungi for their evaluation against the plant parasitic nematode Nacobbus aberrans.

The plant-parasitic nematode Nacobbus aberrans is an endoparasite causing severe losses to a wide range of crops from North to South America. The use of native antagonistic fungi may be considered as a possible biological control alternative to reduce the damages caused by this species. Antagonistic effects of 66 potential nematophagous fungi against eggs (J1) and second-stage juveniles (J2) of N. aberrans, were evaluated in vitro on water agar. DGC test showed significant differences (p < 0.0001) in the efficacy of some fungal isolates tested, with parasitism levels for J1 and J2 of 0-95 and 1-78%, respectively. Five isolates of Purpureocillium lilacinum, Metarhizium robertsii and Plectosphaerella plurivora appeared as the most effective antagonists of N. aberrans, relying on hyphae and adhesive conidia in host infection processes.

Checklist for the crop weeds of Paraguay.

Paraguay, a country whose economy is based mainly on agriculture and livestock for export, has experienced a major expansion in mechanized crops during the last few decades. Despite being heavily dependent on agriculture, Paraguay has very limited research on crop weeds, in spite of these having a high economic impact on production. This work aims to update and enhance the knowledgebase on the most common weeds affecting productive fields throughout the different ecoregions of Paraguay. We present here the first checklist of crop weeds for the country, which includes a total of 256 taxa (189 species, 10 subspecies, 54 varieties and 3 forms), with the most species-rich families being Poaceae and Asteraceae followed by Malvaceae, Amaranthaceae, Fabaceae and Solanaceae. The list includes three new records for the country. Synonyms, distribution details within Paraguay, habit and a voucher specimen are provided for each taxon.

Propuesta de metodología de gestión ambiental para agro ecosistemas con riesgos a la salud por contaminación química / Proposed methodology of environmental management for agro ecosystems health risks for chemical contamination

Introducción: la gestión ambiental relaciona al ser humano como especie a su pasado y se dirige a caracterizar el presente para prever el futuro. Para lograr alcanzar un adecuado desarrollo de la actividad agrícola urbana se hace necesario emplear enfoques más integradores que logren visualizar los problemas ambientales que se presentan en el contexto agrícola actual. Objetivo: desarrollar una metodología de gestión ambiental para agroecosistemas con probables riesgos a la salud por presencia de contaminación química. Material y Métodos: se utilizaron los métodos teóricos de la investigación: histórico-lógico, análisis y síntesis, inductivo-deductivo e hipotético-deductivo. A partir del modelo conceptual de gestión ambiental para agroecosistemas con probables riesgos a la salud por contaminación química, se desarrolló la metodología, como una forma de llevar a la práctica la concepción teórica desarrollada. Resultados: la metodología relaciona coherentemente procedimientos y herramientas por medio de un proceso que transita por cuatro etapas y doce pasos. Estas etapas consisten en preparar, planear, ejecutar, controlar y evaluar las acciones que desde la gestión ambiental son necesarias para las transformaciones de los agroecosistemas contaminados y que influyen directamente sobre la salud humana, mediante un proceso cíclico e iterativo. Conclusiones: permite establecer un conjunto de acciones que son monitoreadas, y evaluadas de forma participativa entre los actores involucrados, lo que permite lograr el empoderamiento de los mismos con mejoras en la salud de los agroecosistemas y la salud de los pobladores(AU)

Introduction: environmental management related to humans like a species to its past and heads to characterize the present to predict the future. In order to reach a proper development of urban agriculture is necessary to use more integrative approaches that achieve visualize environmental problems that arise in the current agricultural context. Objective: to develop a methodology for environmental management for agro ecosystems with probable health risks due to the presence of chemical contamination. Material and Methods: historical and logical analysis and synthesis, deductive and inductive- hypothetical- deductive theoretical research methods were used. A conceptual model of environmental management for agro ecosystems likely risks to health from chemical contamination, the methodology was developed as a way to implement the theoretical concepts developed. Results: the methodology consistently related procedures and tools through a process that goes through four stages and twelve steps. These steps are to prepare, plan, implement, monitor and evaluate the actions that are necessary for environmental management for transformations of contaminated agro ecosystems and that directly influence human health through a cyclical and iterative process. Conclusions: sets a set of actions that are monitored and evaluated in a participatory manner among stakeholders, allowing the empowerment thereof with improved agro-ecosystem health and the health of the inhabitants(AU)

Efecto del cambio del paisaje en la estructura de la comunidad de abejas sin aguijón (Hymenoptera: Apidae) en Meta, Colombia

Effect of landscape change on the structure of the sting-less bee community (Hymenoptera: Apidae) in Meta, Colombia. Stingless bees represent one of the most diversified components of the natural Apoidea fauna of pollinators in the tropics. They use diverse kinds of substrates and inhabit varied habitats. Some species are typical for some natural either artificial place. The landscape alteration were this group of bees nests, has and important impact on the natural composition of its community structure, fact which is reflected in the nest density. We analyzed the structure composition of the stingless bees’ community in three environments in the Colombian llanos piedmont, an important region that represents the transition between Andean ecosystems and a savannah that is seriously threatened by cattle practices. We made systematic samples in secondary forest, agro-ecosystems and urban areas, recording the presence of 204 nests from 11 genera (24 species). The nest density per landscape was heterogeneous and never higher than 16 nests/Ha. We observed two nesting patterns and an effect of sampling criterion on the measured biodiversity. Rev. Biol. Trop. 56 (3): 1295-1308. Epub 2008 September 30.

Las abejas sin aguijón son unos de los polinizadores naturales más diversos de la fauna Apoidea en los trópicos. Nidifican en diversos sustratos y distintos ambientes, existiendo algunas especies típicas de lugares naturales o artificiales. La alteración del medio donde nidifican tiene un importante impacto sobre la composición natural de su estructura, hecho que se ve reflejado también en la densidad de nidos. Analizamos la composición de la estructura de la comunidad de abejas sin aguijón en tres paisajes del piedemonte llanero colombiano, una región importante por representar la transición entre ambientes andinos y de sabana (seriamente amenazada por la ganadería intensiva). Realizamos muestreos sistemáticos en bosque secundario, agro-ecosistema y zona urbana; registramos la presencia de 204 nidos de 11 géneros representados por 24 especies. La riqueza de abejas sin aguijón fue similar, aun cuando hubo diferencias significativas en la estructura de la comunidad en los tres paisajes. La densidad de nidos por paisaje fue heterogénea y nunca mayor de 16 nidos/Ha. Observamos dos patrones de nidificación y registramos diferente número de especies en la misma zona utilizando otro criterio de muestreo.