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88 resultados encontrados para: AUTOR: Pohlan, Jurgen
11.
- Artículo con arbitraje
Integriertes anbaumanagement im zuckerrohr (Saccharum spp.) und seine einflüsse auf das agrarökosystem – Erfahrungen aus Chiapas, Mexiko
Pohlan, Jurgen ; Toledo Toledo, Ernesto (coaut.) ; Leyva Galán, C. Ángel (coaut.) ; Marroquín Agréda, Francisco Javier (coaut.) ; Borgman, J. (coaut.) ;
Contenido en: Journal of Plant Diseases and Protection = Zeitschrift für Pflanzenkrankheiten und Pflanzenschutz Special Issue, Sonderheft XX, (2006), p. 635-642 ISSN: 1861-4051
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Resumen en: Inglés | Alemán |
Resumen en inglés

Sugarcane is grown on 12.000 ha and hence represents one of the most economically important crops in the Soconusco, Chiapas. Since more than 30 years sugarcane has been cropped with double burning every year (before and after harvest), combined with intensive use of herbicides and of mechanical weeding to guarantee weed free sugarcane fields. These practices selected persistent weed species (Cynodon dactylon) and reduced soil fertility and stability of the agro ecosystem. Since 1998 the effects of integrated cropping management have been analyzed in a long-term experiment. This trial is carried out in Huixtla, Chiapas, and consists of an experimental design with strip system (3 x 100 x 32,5 m) including three cropping management systems (no burning as opposed to one and two burnings), and is laid out in a block design with four repetitions. During eight years, the different cropping management and the growth parameters of sugarcane (stalk height, diameter and number of stalks, juice purity, sugar yield and cost-benefit ratio) were monitored monthly as well as the dynamics of abundance, dominance and diversity of weed communities. Results point towards overwhelming advantage of cutting sugarcane green not only for achieving better growth, higher juice purity and sugar yield but also as a strategy for sustaining long-term reduction of weed aggressiveness off-set by a greater sugarcane biomass production (i.e. stalk height, diameter and number of stalks). Furthermore, differences were noted as to pH as well as to soil organic matter, nitrogen, potassium and phosphorus content. Also were increased earthworm abundance and diversity of formicidae. Double burning of sugarcane resulted in greater weed abundance and dominance. Cropping cane without burning showed a much higher income (2684 €/ha) in comparison with one burning (1964 €/ha) and two burnings (1366 €/ha).

Resumen en alemán

Das Zuckerrohr zählt mit 12.000 ha zu den vier wichtigsten Kulturpflanzenarten im Soconusco, Chiapas. Seit mehr als 30 Jahren dominiert die Anbaupraxis mit doppeltem Brennen (vor und nach der Ernte). Damit sollten ursprünglich die Ernte erleichtert sowie unkrautbekämpfende Effekte und eine höhere Herbizideffizienz erreicht werden. Langfristig erfolgte jedoch eine Selektion der schwerbekämpfbaren Unkrautart Cynodon dactylon, die Bodenfruchtbarkeit nahm ab und die Stabilität des Agrarökosystems wurde reduziert. Die Einflüsse eines integrierten Anbaumanagements werden seit 1998 in einem Feldversuch mit Streifenanlage auf 9.750 m² (3 x 100 x 32,5 m), in Huixtla, Chiapas, untersucht. Die Streifenanlage ist als Blockanlage mit vier Wiederholungen eingerichtet. Als Versuchsglieder sind einbezogen: Zuckerrohr nicht gebrannt, Zuckerrohr einmal und zweimal gebrannt. Es werden mehrmals im Anbauzyklus die Abundanz, Biomasse und Diversität der Unkrautzönose ermittelt, physikalische und chemische Bodeneigenschaften bestimmt und Bestandserfassungen von Regenwürmern und Formicidae durchgeführt. Das Anbausystem mit nicht gebranntem Zuckerrohr bewirkte eine starke Abnahme von Abundanz und Dominanz der Unkräuter, erhöhte die organische Substanz sowie N, P und K-Gehalte im Boden und führte zu einer höheren Abundanz von Regenwürmern und der Diversität bei Formicidae. Die Wachstums- und Ertragsparameter des Zuckerrohrs wurden in allen acht Erntejahren signifikant zugunsten des nicht gebrannten Systems beeinflusst. Der Deckungsbeitrag erreicht damit Werte von 2684 €/ha (nicht gebrannt), 1964 €/ha (1x gebrannt) und 1366 €/ha (2x gebrannt).


12.
Tesis - Maestría
Metales pesados en aguas del procesamiento húmedo de café y en ríos de la región del Soconusco, Chiapas / Hermila Yadira Siu Rodas
Siu Rodas, Hermila Yadira ; Sokolov Muratov, Mikhail Yurievich (tutor) ; Pohlan, Jurgen (asesor) ; Mejía Saavedra, José de Jesús (asesor) ; Ruiz García, Antonio Joel (asesor) ;
Tapachula, Chiapas, México : El Colegio de la Frontera Sur , 2006
Clasificación: TE/628.168097275 / S5
Cerrar
SIBE Campeche
ECO040002734 (Disponible)
Disponibles para prestamo: 1
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SIBE Chetumal
ECO030004218 (Disponible)
Disponibles para prestamo: 1
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SIBE San Cristóbal
ECO010006318 (Disponible)
Disponibles para prestamo: 1
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SIBE Tapachula
ECO020009480 (Disponible)
Disponibles para prestamo: 1
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SIBE Villahermosa
ECO050002927 (Disponible)
Disponibles para prestamo: 1
Resumen en español

El café mexicano esta perdiendo mercado internacional, una de las alternativas para conservarlo es produciendo café orgánico y sustentable, que involucra el control de calidad del producto y del ambiente. Uno de los parámetros que exigen los compradores de este tipo de café es la ausencia de metales pesados en el agua que se utiliza en el beneficiado húmedo de café, así mismo las Normas Oficiales Mexicanas establecen límites máximos permisibles de metales en las agua residuales del beneficiado. En este estudio se evaluó por espectroscopia de absorción atómica la presencia de plomo (Pb), cobre (Cu), cadmio (Cd), manganeso (Mn), zinc (Zn), hierro (Fe), níquel (Ni) y arsénico (As) y se realizó una caracterización fisicoquímica mediante la medición de pH, conductividad, turbidez, oxígeno disuelto, cloruros, dureza, fósforo, nitratos y nitrógeno total en el agua utilizada para el procesamiento de café, el agua del proceso de despulpado y del sistema de descarga de tres beneficios húmedos de café de la región del Soconusco, Chiapas, y en los ríos Comaltitlán y Huehuetán que son los que abastecen de agua y a los que descargan directamente las agua residuales estos beneficios. Los resultados obtenidos muestran que el agua que se utiliza en el beneficiado húmedo de café contiene concentraciones traza de Pb, Cu, Cd, Zn y As, y altas concentraciones de Mn y Fe debido a la naturaleza de los ríos, los cuales son diferentes de acuerdo a las características fisicoquímicas. Los niveles de todos los metales pesados analizados se incrementaron en el proceso de despulpado y en la descarga así mismo los parámetros fisicoquímicos medidos a excepción del pH y el oxígeno disuelto que disminuyeron por el alto contenido de materia orgánica que se genera del proceso.

Índice

Resumen
Capitulo 1. Metales pesados en agua del procesamiento húmedo de café y en ríos de la región del Soconusco, Chiapas
I. Introducción
II. Objetivos
III. Metodología
IV. Resultados y Discusión
V. Conclusiones
VI. Bibliografía
VII. Anexos
Capitulo 2. Articulo enviado al Bulletin of Environmental Contamination and Toxicology
Anexos


13.
Libro - Memoria en extenso sin arbitraje
Resúmenes: x congreso internacional de manejo integrado de plagas y agroecología / Alfredo Castillo, Jaime Gómez, Helda Morales, Jorge Toledo y Ramón Jarquín, editores
Congreso Internacional de Manejo Integrado de Plagas y Agroecología (X : 2006 : Tapachula, Chiapas, México) ; Castillo Vera, Alfredo (editor) ; Gómez Ruiz, Jaime (editor) ; Morales, H. (editora) ; Toledo, Jorge (editor) ; Jarquín Gálvez, Ramón (editor) ;
Tapachula, Chiapas, México : El Colegio de la Frontera Sur , 2006
Disponible en línea
Clasificación: EE/632.909728 / C6
Bibliotecas: San Cristóbal , Tapachula
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SIBE San Cristóbal
ECO010017204 (Disponible) , 41468-30 (Disponible) , ECO010003612 (Disponible)
Disponibles para prestamo: 3
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SIBE Tapachula
41468-40 (Disponible) , ECO020011320 (Disponible)
Disponibles para prestamo: 2
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14.
Capítulo de libro
*Solicítelo con su bibliotecario/a
La agricultura ecológica sostenible, otro punto de vista: oportunidades y obstáculos para el futuro
Pohlan, Jurgen (autor) ;
Contenido en: Agroecología en el trópico - ejemplos de Cuba: la biodiversidad vegetal, cómo conservarla y multiplicarla / Ángel Leyva Galán, Jürgen Pohlan Aachen, Germany : Shaker Verlag, 2005 p. 45-58 ISBN:38-322-3814-X, 978-3832238148
Bibliotecas: Tapachula , Villahermosa
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SIBE Tapachula
58247-10 (Disponible)
Disponibles para prestamo: 1
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SIBE Villahermosa
58247-20 (Disponible)
Disponibles para prestamo: 1
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15.
Libro
Agroecología en el trópico - ejemplos de Cuba: la biodiversidad vegetal, cómo conservarla y multiplicarla / Ángel Leyva Galán, Jürgen Pohlan
Leyva Galán, C. Ángel ; Pohlan, Jurgen (coaut.) ;
Aachen, Germany : Shaker Verlag , 2005
Clasificación: 634.99 / L4
Bibliotecas: Tapachula , Villahermosa
Cerrar
SIBE Tapachula
ECO020008080 (Disponible)
Disponibles para prestamo: 1
Cerrar
SIBE Villahermosa
ECO050005658 (Disponible)
Disponibles para prestamo: 1

16.
Artículo
Alternatives for the transformation of drug production areas in the Chapare Region, Bolivia
Torrico, Juan Carlos ; Pohlan, Jurgen (coaut.) ; Janssens, Marc J. J. (coaut.) ;
Clasificación: AR/583.60984 :: T6
Contenido en: Journal of Food, Agriculture & Environment Vol. 3, no. 3-4 (2005), p. 167-172 ISSN: 1459-0263
Bibliotecas: San Cristóbal
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SIBE San Cristóbal
ECO010019024 (Disponible)
Disponibles para prestamo: 1
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Resumen en: Inglés |
Resumen en inglés

The Chapare region of Bolivia is classified as “humid sub-tropic”. About 92% of the 35,000 families of inhabitants are involved in farming. Until now, 93% of the coca (Erythroxylum coca Lam.) cultivation has been eradicated leading to serious social, economic and ecological problems. The most important agricultural crops grown in the Chapare region are citrus and banana, which occupy 20.8 and 18.8% of the total area under cultivation, respectively. Both crops are intended for the market and therefore play an important role in the economy of the region. Cassava (7.3%) and rice (7.2%) are cultivated for personal consumption. The average area of land possessed by a family amounts to 10.4 ha, but due to lack of capital and high labour costs, only 2.6 ha/family are cultivated. The remaining land (74%) is under forest and fallow. Generally, poor quality seeds are used. The intensive use of agrochemicals is common in the area. Clearing vegetation by burning (chaqueo) is a common activity that causes severe ecological damage. The crops are grown in small plots on small farms and the neighbouring families provide the labour force engaged in crop husbandry and other agricultural activities. The average available family wage is 460 US dollars/year/ha. Sixty five percent of the farms belong to the subsistence economy. They have an average investment capacity of 400- 800 US$/ha (representing 89% of the cases). Alternative cultivation products include banana, pepper, passion fruit, pineapple and palmito, but these provide a limited income (600-2400 US$/ha), which only represents a third to a sixth of the proceeds from coca. The initial investments for alternative crops can ascend to US$1800-5000 provided that proper management and good technical knowledge are made available. The alternative crops available at present do not provide an economically feasible opportunity for the families of this region.

Research should be focused on other alternative crops for sustainable production leading to improved agricultural commercialisation which reinforces the national market. In addition, greater attention needs to be paid to the social aspects of the present problem.


17.
Capítulo de libro - Memoria en extenso sin arbitraje
Conversion process and reforestation practices of coffee plantations in Chiapas, Mexico
Jende, Oliver ; Pohlan, Jurgen (coaut.) ; Janssens, Marc J. J. (coaut.) ;
Contenido en: Tropentag. Conference on International Agricultural Research for Development (October 2005), p. 11-13
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Resumen en: Inglés |
Resumen en inglés

The Agro-ecosystems in the Tropics are nowadays mostly based on annual monocultures. Typically, big forest areas are chopped down and burned with all their biodiversity and complex food chains, to give space to simplified systems reminescent of shifting cultivation. However, the traditional long-term fallowing of exhausted soils is reduced. With perennial crop systems the negative effects of forest logging are mitigated. Today, more than 25 million families on 12 million ha in 50 countries over the World are socially and economically dependent from coffee plantations. The low coffee prices in the world market harm not only these families but also the agro ecosystem coffee, which protects naturally a still considerable flora and fauna (POHLAN, 2002). Chiapas is the most important coffee producing state of Mexico with 31% of the national coffee production. Coffee agro ecosystems in the Soconusco area in Chiapas are under pressure due to these low coffee prices in the world market (RENARD, 2002; KRAUSE, 2002). Coffee farmers have to adapt to this situation by producing high quality coffee with added value through certification labels, or changing the coffee plantations into other more profitable crops (POHLAN, 2002). One of the possibilities for lower tropical areas is the production of high value tropical timber, which can be planted between coffee rows (JENDE, 2005). These agroforestry systems offer also a high potential for environmental services, like conservation of biodiversity, carbon fixation, erosion control and water shed management, what could be used as incentive alternatives for farmers by decision makers (KÖTZ, 2003; BAUMANN, 2002; PERFECTO, 2002; CONAFOR, 2001; DE JONG, 2000). In this study, different aspects of a gradual conversion process from coffee to timber production were evaluated, with the aim to understand, how the agro-ecosystem coffee changes in horizontal and vertical structure, in terms of biomass components, and which ecological


18.
Tesis - Maestría
The conversion process of Chiapas coffee plantations through agroforestry into timber production and its ecological implications / Oliver Jende
Jende, Oliver ; Pohlan, Jurgen (tutor) ; Janssens, Marc J. J. (asesor) ; Wittmann, Dieter (asesor) ;
Bonn, Deutschland : Universität Bonn-Wilhelms. Institut für Gartenbauwissenschaft. Rheinischen Friedrich , 2005
Clasificación: TE/633.73097275 / J4
Bibliotecas: San Cristóbal , Tapachula
Cerrar
SIBE San Cristóbal
ECO010009567 (Disponible)
Disponibles para prestamo: 1
Cerrar
SIBE Tapachula
ECO020012141 (Disponible) , ECO020011301 (Disponible)
Disponibles para prestamo: 2

19.
Artículo
Effects of production systems with maize (Zea mays L.) on soil fertility and biological diversity in the Soconusco, Chiapas, Mexico
Marroquín Agréda, Francisco Javier ; Pohlan, Jurgen (coaut.) ; Janssens, Marc J. J. (coaut.) ; Borgman, Jörg (coaut.) ;
Contenido en: The Global Food & Product Chain – Dynamics, Innovations, Conflicts, Strategies. ID 389. Deutscher Tropentag, October 11 - 13, 2005 in Stuttgart p. 1-6
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Resumen en: Inglés |
Resumen en inglés

The abuse of chemical products in the production systems in the Central American tropical region has caused a series of drastic effects on the natural resources leading to the lowering of yields at medium and long terms. It also destroys sustainable production and depends highly on external inputs such as fertilizers and pesticides. The objectives of the research were to analyze the bases for the implementation of sustainable agriculture practices in Chiapas agricultural systems with maize. The investigation was carried out during cropping cycle 2002–2003 in the region of the Soconusco, Chiapas, Mexico. Four treatments with experimental areas of one hectare each were selected: (i) production system with maize (roza-tumba-quema = slash and burn) with 2 years cropping; (ii) production system with 6 years monoculture maize; (iii) production system with 12 years monoculture maize; (iv) area with tropical rain forest. In each experimental unit the physical and chemical soil properties, the dynamic of weed populations and the productivity of each system were determined, a one-way experimental design with seven levels was applied, each level with four repetitions. The dynamic of the soil fertility of the production systems with maize, indicates that the content of organic C, N total, K, Ca and Mg, was strongly reduced by the duration of maize cultivation. The lowest values were recorded in the maize treatment with 12 years of monoculture, whereas the treatment with 2 years maize cropping demonstrated soil values very similar to the tropical rain forest. To the contrary, P increased in the systems with continuous maize growing.

The weed biomass decreases with maize cropping duration, having the highest biomass production in the treatment with 2 years maize cropping. The diversity of weeds also was reduced by maize cropping duration, encompassing 20 weed species in the treatment with 2 years maize cropping followed with 17 weed species in the 6 years maize monoculture and only 12 weed species in the treatment with 12 years of maize monoculture. The maize yield oscillates significantly between 4353 kg*ha−1 (2 years maize cropping) and 1785 kg*ha−1 (12 years of maize monoculture).


20.
Capítulo de libro
*Solicítelo con su bibliotecario/a
Establecimiento de cultivos de plantas medicinales en agroecosistemas tropicales
Pohlan, Jurgen ; Leyva Galán, C. Ángel (coaut.) ; Gamboa Moya, William Gerardo (coaut.) ;
Contenido en: Memorias en extenso. Primer congreso internacional de plantas medicinales en Villahermosa, Tabasco, México, 2005, CD-ROM p. 13- 25
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