Mostrando recursos 1 - 20 de 2.452

  1. Effect of level of fiber of the rearing phase diets on egg production, digestive tract traits, and body measurements of brown egg-laying hens fed diets differing in energy concentration

    Guzmán Medina, María del Pilar; Saldaña, B.; Bouali, O.; Cámara, L.; Mateos, G.G.
    This research studied the effects of additional fiber in the rearing phase diets on egg production, gastrointestinal tract (GIT) traits, and body measurements of brown egg-laying hens fed diets varying in energy concentration from 17 to 46 wk of age. The experiment was completely randomized with 10 treatments arranged as a 5 × 2 factorial with 5 rearing phase diets and 2 laying phase diets. During the rearing phase, treatments consisted of a control diet based on cereals and soybean meal and 4 additional diets with a combination of 2 fiber sources (cereal straw and sugar beet pulp, SBP) at...

  2. Use of tomato and cucumber horticulture by-products in goat diets: effects o nrumen fermentation and microbial communities in batch and continuous cultures

    Soto, E. C.; Khelil, H.; Carro Travieso, María Dolores; Yáñez Ruiz, David; Molina Alcaide, Eduarda
    Two in vitro experiments were conducted to analyse the effects of replacing dietary barley grain with wastes of tomato and cucumber fruits and a 1 : 1 tomato : cucumber mixture on rumen fermentation characteristics and microbial abundance. The control (CON) substrate contained 250 g/kg of barley grain on a dry matter (DM) basis, and another 15 substrates were formulated by replacing 50, 100, 150, 200 or 250 g of barley grain/kg with the same amount (DM basis) of tomato or cucumber fruits or 1 : 1 tomato : cucumber mixture. In Expt 1, all substrates were incubated in batch...

  3. Las contribucuiones de la agricultura y la silvicultura a la acción climática

  4. Carbono orgánico del suelo en rodales silvícolas del ejido La Victoria, Pueblo Nuevo, Durango

    Solís Hernández, Adalberto; Nájera Luna, Juan Abel; Méndez González, Jorge; Vargas-Larreta, Benedicto; Álvarez Gallegos, Manuel
    The objective of this research was to quantify the organic carbon content in the soil at the common land La Victoria, Pueblo Nuevo, Durango. Soil samples were collected at 108 sites distributed in three site qualities, three silvicultural treatments and three soil depths. The determination of organic carbon content was estimated by the Walkley and Black method. To identify significant differences in the content of organic carbon in the soil for site qualities, silviculture treatments and soil depths, we performed analysis of variance and comparison of means by Tukey�s test at 95%. The results showed an average soil organic carbon of 58.10 mg ha-1, with an increase in carbon as site quality improvement....

  5. Leptospira: revisión del agente causal de una enfermedad zoonótica

    Chavarría Joya, Luzlady; Lara Gutiérrez, Daniela; Méndez Hurtado, William; Moscoso Gama, Johanna
    La leptospirosis es una enfermedad zoonótica reemergente, tiene comportamiento endémico y es de gran importancia en la salud pública a nivel mundial. Su prevalencia es alta en países tropicales y subtropicales, pero presenta mayor incidencia en lugares donde es frecuente la agricultura, la manufactura de productos animales, la silvicultura, la ganadería, entre otros.Esta patología tiene un porcentaje elevado de mortalidad y aunque generalmente es subclínica, puede producir síntomas que van desde un resfriado común hasta fiebre hemorrágica, es por esto que se confunde fácilmente con otras patologías evitando que sea tratada oportunamente.Su forma crónica puede generar alteraciones sistémicas a nivel...

  6. Implicaciones del Acuerdo de París en los sectores relacionados con los usos de la tierra, cambios de uso de la tierra y la silvicultura

    Prado, Agustín del; Sanz, María José

  7. Evaluación de requerimientos nutricionales en vivero de especies tropicales empleadas en silvicultura urbana

    Herrera Ramírez, David Andrés; León Peláez, Juan Diego; Ruiz Rendón, Mónica; Osorio Vega, Nelson Walter; Correa Londoño, Guillermo; Ricardo, Ricardo Esteban; Uribe Bravo, Ángela
    One of the determining factors in urban tree development and growth is fertilization. We therefore studied the nutritional requirements of five tree species used in urban forestry (Tabebuia chrysantha, Margaritaria nobilis, Hamelia patens, Apeiba aspera, Cupania americana) using the missing element technique. Differential responses by groups were found for nitrogen and sulfur deficiencies. The T. chrysanta, M. nobilis, and H. patens groups showed high sensitivity to nitrogen deficiencies. This was evident in a lower mean growth for all variables assessed: height, root neck diameter, aerial dry matter, and radical dry matter. The C. americana and A. aspera group showed the...

  8. Effects of early fertilization on the performance of Nothofagus dombeyi planted in the Coastal Range of south-central Chile

    Donoso, Pablo J.; Soto, Daniel P.; Schlatter, Juan E.; Büchner, Carlos A.
    Native Nothofagus dombeyi growth rates excel in secondary forests and in some plantations, and the species has good timber quality. However, few have reported on the effects of fertilization on N. dombeyi plantations. This is a key matter since fertilization has environmental and financial costs, and therefore its use to increase growth and survival for production or restoration must be carefully evaluated. Here we evaluated the early effects of fertilization (control and three levels) using several performance variables (leaf properties, growth, plant quality, and survival) in a N. dombeyi plantation at a low elevation in the Coastal Range of south-central...

  9. Treatment of tropical forages with exogenous fibrolytiic enzymes: effects on chemical composition and in vitro rumen fermentation

    Díaz, A.; Ranilla, J. M.; Giraldo, L. A.; Tejido, M. L.; Carro Travieso, María Dolores
    The effects of three treatments of fibrolytic enzymes (cellulase from Trichoderma longibrachiatum (CEL), xylanase from rumen micro-organisms (XYL) and a 1:1 mixture of CEL and XYL (MIX) on the in vitro fermentation of two samples of Pennisetum clandestinum (P1 and P2), two samples of Dichanthium aristatum (D1 and D2) and one sample of each Acacia decurrens and Acacia mangium (A1 and A2) were investigated. The first experiment compared the effects of two methods of applying the enzymes to forages, either at the time of incubation or 24 h before, on the in vitro gas production. In general, the 24 h...

  10. Estimating leaf area index in Southeast Alaska: a comparison of two techniques.

    Carolyn A Eckrich; Elizabeth A Flaherty; Merav Ben-David
    The relationship between canopy structure and light transmission to the forest floor is of particular interest for studying the effects of succession, timber harvest, and silviculture prescriptions on understory plants and trees. Indirect measurements of leaf area index (LAI) estimated using gap fraction analysis with linear and hemispheric sensors have been commonly used to assess radiation interception by the canopy, although the two methods often yield inconsistent results. We compared simultaneously obtained measurements of LAI from a linear ceptometer and digital hemispheric photography in 21 forest stands on Prince of Wales Island, Alaska. We assessed the relationship between these estimates...

  11. Intercropped silviculture systems, a key to achieving soil fungal community management in eucalyptus plantations.

    Caio T C C Rachid; Fabiano C Balieiro; Eduardo S Fonseca; Raquel Silva Peixoto; Guilherme M Chaer; James M Tiedje; Alexandre S Rosado
    Fungi are ubiquitous and important contributors to soil nutrient cycling, playing a vital role in C, N and P turnover, with many fungi having direct beneficial relationships with plants. However, the factors that modulate the soil fungal community are poorly understood. We studied the degree to which the composition of tree species affected the soil fungal community structure and diversity by pyrosequencing the 28S rRNA gene in soil DNA. We were also interested in whether intercropping (mixed plantation of two plant species) could be used to select fungal species. More than 50,000 high quality sequences were analyzed from three treatments:...

  12. Breeding Bird Community Continues to Colonize Riparian Buffers Ten Years after Harvest.

    Scott F Pearson; Jack Giovanini; Jay E Jones; Andrew J Kroll
    Riparian ecosystems integrate aquatic and terrestrial communities and often contain unique assemblages of flora and fauna. Retention of forested buffers along riparian habitats is a commonly employed practice to reduce potential negative effects of land use on aquatic systems. However, very few studies have examined long-term population and community responses to buffers, leading to considerable uncertainty about effectiveness of this practice for achieving conservation and management outcomes. We examined short- (1-2 years) and long-term (~10 years) avian community responses (occupancy and abundance) to riparian buffer prescriptions to clearcut logging silvicultural practices in the Pacific Northwest USA. We used a Before-After-Control-Impact...

  13. Logging affects fledgling sex ratios and baseline corticosterone in a forest songbird.

    Rhiannon Leshyk; Erica Nol; Dawn M Burke; Gary Burness
    Silviculture (logging) creates a disturbance to forested environments. The degree to which forests are modified depends on the logging prescription and forest stand characteristics. In this study we compared the effects of two methods of group-selection ("moderate" and "heavy") silviculture (GSS) and undisturbed reference stands on stress and offspring sex ratios of a forest interior species, the Ovenbird (Seiurus aurocapilla), in Algonquin Provincial Park, Canada. Blood samples were taken from nestlings for corticosterone and molecular sexing. We found that logging creates a disturbance that is stressful for nestling Ovenbirds, as illustrated by elevated baseline corticosterone in cut sites. Ovenbirds nesting...

  14. Regeneration of a coastal pine (Pinus thunbergii Parl.) forest 11 years after thinning, Niigata, Japan.

    Jiaojun Zhu; Yutaka Gonda; Lizhong Yu; Fengqin Li; Qiaoling Yan; Yirong Sun
    To examine the effects of thinning intensity on wind vulnerability and regeneration in a coastal pine (Pinus thunbergii) forest, thinning with intensities of 20%, 30% and 50% was conducted in December 1997; there was an unthinned treatment as the control (total 8 stands). We re-measured the permanent sites to assess the regeneration characteristics 11 years after thinning. In the 50% thinned stand, seedlings aged from 2 to 10 years exhibited the highest pine seedling density and growth. The age composition ranged from 1-3 years with densities of 9.9 and 5.1 seedlings m(-2) in 30% and 20% thinned stands; only 1-year-old...

  15. A trait database for Guianan rain forest trees permits intra- and inter-specific contrasts

    Ollivier, Mariwenn; Baraloto, Christopher; Marcon, Eric
    International audience

  16. Evaluación de la recarga producida mediante manejo de una masa de Pinus halepensis con técnicas de silvicultura hidrológica

    García Prats, Alberto; Campo García, Antonio Dámaso Del; MOLINA HERRERA, ANTONIO
    [ES] El balance hídrico, y especialmente la recarga por percolación profunda de un suelo, puede ser modificado a nivel de parcela mediante el manejo de la masa. Extendido a nivel de cuenca debemos esperar que dicha modificación afecte al conjunto del ciclo hidrológico. Sin embargo, el primer paso es la cuantificación del efecto que produce sobre el balance de agua el manejo silvícola de la masa con fines hidrológicos a nivel de parcela. Para ello se diseñó un experimento en una parcela de Pinus halepensis en la que se realizaron aclareos de distinta intensidad. El ciclo del agua se monitorizó...

  17. Maintaining the coexistence of tree species of different shade tolerances with uneven-aged silviculture

    Ligot, Gauthier; Balandier, Philippe; Courbaud, Benoît; Kneeshaw, Daniel; Claessens, Hugues
    Peer reviewed

  18. Evolution-based approach needed for the conservation and silviculture of peripheral forest tree populations

    Fady, Bruno; Aravanopoulos, Filippos A.; Alizoti, Paraskevi; Mátyás, Csaba; von Wühlisch, Georg; Westergren, Marjana; Belletti, Piero; Cvjetkovic, Branislav; Ducci, Fulvio; Huber, Gerhard; Kelleher, Colin T.; Khaldi, Abdelhamid; Kharrat, Magda Bou Dagher; Kraigher, Hojka; Kramer, Koen; Mühlethaler, Urs; Peric, Sanja; Perry, Annika; Rousi, Matti; Sbay, Hassan; Stojnic, Srdjan; Tijardovic, Martina; Tsvetkov, Ivaylo; Varela, Maria Carolina; Vendramin, Giovanni G.; Zlatanov, Tzvetan
    The fate of peripheral forest tree populations is of particular interest in the context of climate change. These populations may concurrently be those where the most significant evolutionary changes will occur; those most facing increasing extinction risk; the source of migrants for the colonization of new areas at leading edges; or the source of genetic novelty for reinforcing standing genetic variation in various parts of the range. Deciding which strategy to implement for conserving and sustainably using the genetic resources of peripheral forest tree populations is a challenge. Here, we review the genetic and ecological processes acting on different types...

  19. Morfología, anatomía externa, y taxonomía de himenópteros basales (Hymenoptera:"Symphyta") de Colombia

    Malagón Aldana, Leonardo Andrés
    “Symphyta” reúne varias familias basales de himenópteros, principalmente avispas fitófagas, de las cuales algunas especies actúan como plagas en la silvicultura o la agricultura. Con el fin de establecer un marco básico para la morfología y taxonomía de estas avispas en Colombia, como uno de los soportes fundamentales de los programas de manejo integrados de insectos plagas e insectos benéficos, el objetivo de este estudio fue explorar la anatomía externa y la morfología de “Symphyta”, así como su taxonomía en el país. Por lo tanto, se describió y analizó la anatomía externa de adultos de las especies Stromboceridea albilabris (Tenthredinidae), Perreyia tropica (Pergidae), Tanymeles sp. (Argidae), Derecyrta sp....

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    Galopin, Gilles; MAUGET, Jean-Claude; Morel, Philippe
    International audience

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