ABSTRACT Soil CO2 emissions are formed from biotic and abiotic processes related to organic carbon (SOC) and inorganic carbon (SIC), respectively. Calcareous soil has a high amount of SIC and occurs mainly in arid areas, and little is known about CO2 emissions from aggregates of this soil. This study aims to evaluate the emission of CO2 of aggregates from calcareous soil in the Comarca Lagunera, Mexico. Soil samples were taken from the layers of 0.00-0.15 and 0.15-0.30 m, and soil physical and chemical properties were determined. Aggregates distribution was obtained using the dry-sieving method. Macro (0.25–0.149 mm), meso (0.149–0.074 mm) and microaggregates (<0.074 mm) were selected for incubation in a dynamic closed system for 30 days under two moisture contents (15 and 30 %, dry weight basis). The CO2 emissions were quantified using a non-dispersive infrared gas analyzer (IRGA). From total carbon measured, 97 % were found to be SIC. Soil texture is a sandy clay loam with a field capacity and a permanent wilting point of 27 and 17 %, respectively. From whole soil aggregates, 60 % were distributed in fractions lower than 0.25 mm diameter, which are highly erodible by the wind. Soil moisture content had a significant effect on the emission of CO2. The highest accumulated CO2 emission was registered in the superficial layer (0.00-0.15 m) within 0.25 mm aggregates (29.4 g m-2 h-1), which turned out higher than reported for similar areas. The CO2 emissions were attributed to the dissolution - reprecipitation process of high concentrations of SIC present in soil, involving a considerable contribution of CO2 to the atmosphere.

Abstract Background: Currently, the chinantec Mexican ethnic group has received little ethnomycological attention, despite the precise and profuse traditional knowledge that it has related to its fungal resource. Objective: To document the traditional knowledge related to the use and importance of wild mushrooms by the chinantec people. Methodology: During May to October 2018, visits to seven chinantec communities were conducted. Through unstructured, semi-structured and structured surveys, 10 % of the population of each of these communities were interviewed. In addition, field work was carried out with local experts where sporomes were collected. Results and conclusions: Thirty-six species used by the chinantec people were registered, of which 31 are consumed and prepared in eight different ways; three are used in traditional medicine, and two are used with ludic purposes. In addition, 27 names were reported in chinantec language, which in all cases have the root “Níẗ” or “Naẗ” that means fungus, followed by two or three adjectives that refer to elements of the chinantec worldview. The present work analyses the biocultural importance of wild mushrooms in the millennian chinantec group.

Resumen Antecedentes: Actualmente, el grupo originario chinanteco ha recibido escasa atención etnomicológica, a pesar del conocimiento tradicional preciso y profuso que posee dicha etnia relacionado con el recurso fúngico. Objetivo: Documentar los saberes tradicionales relacionados con el uso y aprovechamiento de los hongos silvestres por los chinantecos. Metodología: Durante mayo a octubre de 2018, se realizaron visitas a siete comunidades chinantecas. Mediante preguntas no estructuradas, semiestructuradas y estructuradas, se entrevistó a 10 % de la población de cada una de estas. Además, se llevaron a cabo recorridos con expertos locales para la recolección de esporomas. Resultados y conclusiones: Se registraron 36 especies utilizadas por los chinantecos, de las cuales 31 son consumidas y preparadas de ocho formas diferentes; tres son utilizadas en la medicina tradicional, y dos utilizadas con fines lúdicos. Además, se reportaron 27 nombres en chinanteco, los cuales, en todos los casos presentan la raíz “Níẗ” o “Naẗ” que significa hongo, seguido de dos o tres adjetivos que hacen alusión a elementos de la cosmovisión chinanteca. En el presente trabajo se analiza la importancia biocultural de los hongos silvestres en el grupo milenario chinanteco.

Aerial fire fighting with a helicopter is a usual practice in Mexico State, the availability of water near to the wildfire area is crucial to refill the bucket and reduce the time between successive drops. Rain Water Harvesting system (RWH) can be used to supply water for the helicopter to combat wildfires. Identification of potential sites for RWH at places with high recurrence of wildfire is essential to improve the efficiency of the practice. However, selection of appropriate sites for RWH requires the integration of several variables. The identification of suitability sites for RWH was achieved using a multicriteria spatial analysis in a Geographical Information System (GIS) environment at the East of Mexico State, for three municipalities Chalco, Ixtapaluca and Tlalmanalco. Five variables were used to identify suitable sites for RHW: wind speed, wildfire density, distance to roads, runoff and evaporation. Each variable was ranked and weighted consulting the expert and a Weighted Linear Combination (WLC) was performed to generate the suitability map using Arc Gis 9.2 and Arc View 3.2. Suitability sites for RWH that met most of the criteria considered are found in North and South of the study area. The conclusion is that the identification of suitability sites to establish RWH system to supply water for the helicopter with the proposed method is a rapid and flexible tool. The output suitability map for the study area showed sites for RHW systems ranked from 1 to 10.

El control de incendios forestales con helicópteros es una práctica común en el Estado de México que está limitada por la disponibilidad de fuentes de agua para la recarga de las aeronaves. Los sistemas de captación del agua de lluvia (SCALL) se pueden usar para su abastecimiento. La identificación de sitios con aptitud para SCALL en zonas de alta incidencia de incendios es fundamental para mejorar la eficiencia del control aéreo; sin embargo, la selección de los lugares requiere integrar numerosas variables. En el presente estudio se efectuó un análisis de evaluación multicriterio mediante Sistemas de Información Geográfica (SIG) para identificar los sitios con aptitud para SCALL en el área de interés, para lo cual se eligieron cinco variables: velocidad de ráfaga de viento, distancia a los caminos, escurrimiento superficial, evaporación y densidad de incendios. Las variables fueron ponderadas con el apoyo del coordinador de vuelo de las aeronaves y se integraron en un mapa de aptitud por el método de combinación lineal ponderada en Arc Gis 9.2 y Arc View 3.2. Se detectaron de forma rápida y flexible dos sitios con aptitud para establecer SCALL en el área de estudio: uno al norte y otro al sur; y el mapa que los muestra se elaboró a una escala de 1 a 10.

Mapas de solos locais gerado unidades do mapa diretamente relacionadas às propriedades de solo-paisagem. Portanto, para ter em conta o conhecimento dos agricultores é fundamental para automatizar o processo. O objetivo deste estudo foi realizar a cartografia assistida por computador (CAC) das classes de solos locais, por meio de várias combinações de atributos topográficos produzidos em GIS (modelo numérico do terreno, aspecto, declividade e curvatura do perfil). O método da árvore de decisão foi utilizado para localizar o número de atributos topográficos necessários à produção de cartografia digital das classes de solo. Os mapas produzidos foram avaliados usando o atributo de qualidade do mapa, definido como sua precisão e exatidão dos mapas produzidos pelo CAC. A avaliação foi realizada no centro do México, com três mapas de classes de solos locais com diferentes paisagens e condições climáticas: árida, temperada e tropical. Os resultados mostraram que, nas três áreas estudadas, os mapas produzidos pelo CAC, usando o atributo de elevação como característica topográfica, obtiveram a maior precisão (56 %). No entanto, a exatidão dos mapas (localização dos limites) foi menor: 33 %. Isso significa que a precisão dos mapas produzidos ainda permanece baixa, havendo necessidade de novas pesquisas para melhorar esse indicador.

Map units directly related to properties of soil-landscape are generated by local soil classes. Therefore to take into consideration the knowledge of farmers is essential to automate the procedure. The aim of this study was to map local soil classes by computer-assisted cartography (CAC), using several combinations of topographic properties produced by GIS (digital elevation model, aspect, slope, and profile curvature). A decision tree was used to find the number of topographic properties required for digital cartography of the local soil classes. The maps produced were evaluated based on the attributes of map quality defined as precision and accuracy of the CAC-based maps. The evaluation was carried out in Central Mexico using three maps of local soil classes with contrasting landscape and climatic conditions (desert, temperate, and tropical). In the three areas the precision (56 %) of the CAC maps based on elevation as topographical feature was higher than when based on slope, aspect and profile curvature. The accuracy of the maps (boundary locations) was however low (33 %), in other words, further research is required to improve this indicator.

In the upper part of Cuitzeo Lake watershed, Michoacan, Mexico, farmers use a traditional short-fallow production system. With this system, land is sown one year, and left without cultivation from one to three years for grazing. This system is used mainly on Andisols and Acrisols, and it is supposed to be associated with soil degradation due to low nutrient recycling level and to excessive tillage during the cultivation year. The objective of this study was to measure soil, nutrient and runoff losses under the traditional short-fallow system (AV), and under two alternatives systems: organic (O), and improved traditional (TM) systems. Research was carried out on an Acrisol in the Cointzio sub-watershed, during three years under rainfed conditions on 1 000 m² runoff plots without replications. Results showed that soil losses under all systems were permissible (< 1.2 t ha-1 year-1), except in TM and O in 2002 when the plant coverage was less than 20%, with a significant increase of runoff and nutrient losses when land was left on fallow due to soil surface bulk density increase. This change did not occurred with the O and TM systems, perhaps due to soil tillage effect. Main nutrient losses in the three treatments were: N, Ca2+, Mg2+, Na+, and K+. Above mentioned results suggests that soil degrading effect, under the AV system, is more intense on soils when they are left on fallow than when those are cultivated. Best practice for reducing water, soil, and nutrient losses were: dense crops such as oats, and the use of crop residue cover (30% cover), the last one was also the best management for decrease evaporation. An analysis of soil losses to sub-basin level showed that erosion can be reduced significantly by using crop residues as mulch during crop production (TM).

Los productores agrícolas de la porción alta de la cuenca del Lago de Cuitzeo, Michoacán, usan el sistema denominado "año y vez" (AV), que es una rotación maíz-descanso, la cual consiste en la producción de maíz durante un ciclo y en el posterior la tierra permanece en descanso para el pastoreo del ganado. Este sistema se práctica en Andosoles y Acrisoles principalmente, y se asume que está asociado con la degradación del suelo por su bajo nivel de reciclamiento de nutrientes y por el laboreo excesivo durante el año de cultivo. El objetivo de este trabajo fue medir las pérdidas de suelo, escurrimiento y nutrientes para la rotación "año y vez" (AV) y dos sistemas alternativos: tradicional mejorado (TM) y orgánico (O). La investigación se desarrolló en un Acrisol de la subcuenca de Cointzio durante tres ciclos de cultivo bajo condiciones de temporal, en parcelas de escurrimiento de 1 000 m² sin repeticiones. Los resultados indicaron que todos los sistemas presentaron pérdidas de suelo permisibles (<1 .2 t ha-1 año-1), excepto en TM y O en el año 2002 cuando la cobertura vegetal fue menor de 20%; sin embargo, bajo el sistema AV hubo un aumento significativo en el escurrimiento y con ello mayores pérdidas de nutrientes durante el año de descanso, causados por un aumento en la densidad aparente de la superficie del suelo, cambio que no se presentó en O y TM, quizás por el efecto del laboreo del suelo. Las principales fugas nutrimentales en los tres tratamientos fueron: N, Ca2+, Mg2+, Na+ y K+. Lo anterior sugiere que el sistema AV tiene mayor efecto de degradación en el año de descanso que durante la fase de cultivo. Las mejores prácticas para reducir las pérdidas de agua, suelo y nutrimentos fueron: cultivos tupidos (avena), y el uso de residuos de cosecha como cobertura del suelo (30% de cobertura), este último disminuyó además significativamente la evaporación. Un análisis de la pérdida de suelo a nivel de subcuenca en Acrisoles, mostró que es posible reducir la erosión de manera significativa utilizando cubiertas de residuos de cosecha en la producción de cultivos TM.