Produção de gado de corte e acúmulo de matéria seca em sistemas de integração lavoura: pecuária em presença e ausência de trevo branco e nitrogênio.

O trabalho foi conduzido com o objetivo de verificar a influência da adubação nitrogenada em uma pastagem de azevém (Lolium multiflorium L.) e aveia (Avena strigosa Scherb) em presença e ausência de trevo branco (Trifolium repens L.), conferida pelo acúmulo e produção de matéria seca, ganho médio diário, ganho de peso vivo e carga animal no sistema de integração lavoura-pecuária sob sistema de plantio direto. A cultura antecessora da pastagem foi a soja (Glycine Max L.). O delineamento experimental foi em blocos completos ao acaso, com parcelas subdivididas e três repetições. Nas parcelas, foram testadas quatro doses de nitrogênio (0, 100, 200 e 300 kg.ha-1) e nas subparcelas, a combinação de presença e ausência de trevo branco. A elevação das doses crescentes de N aumentaram de forma linear crescente o acúmulo e a produção de matéria seca da pastagem. A carga animal e o ganho de peso vivo por hectare de bovinos aumentaram com o incremento de nitrogênio. Os resultados demonstram o efeito da adubação nitrogenada no acúmulo diário, na produção de matéria seca, carga animal e no ganho de peso vivo

Período crítico de competição de plantas daninhas com a cultura da erva-mate (Ilex paraguariensis St. Hil.).

bitstream/CNPF-2009-09/44301/1/pesq-andam-76.PD

Production Systems to Integrate Livestock Grazing and Grain Production in Southern Brazil and Midwestern USA

Agriculture in the USA and Brazil has undergone similar and dramatic changes in the past 20 years. In both countries, production systems have become increasingly specialized. Large farms are characterized by single enterprises, simple crop rotations, and livestock production is segregated from grain production. The lack of diversification and high production costs expose producers to risk from economic swings of single enterprises and greater reliance on pesticides and synthetic fertilizers to maintain profitability, along with greater risk of soil erosion from continuous row crop production. Scientists in southern Brazil and Ohio are collaborating to develop no-tillage systems that integrate livestock grazing with cash grain production. The goal is diversified production systems that are profitable as well as biologically and environmentally sound

Spatial patterns and interactions of dominant tree species in an Amazon tropical rainforest.

Knowledge of spatial patterns and interactions of tree species allows for understanding the ecological processes of spatiotemporal structures of tropical forests, becoming essential for the establishment of strategies for the conservation and management of their resources in the long term. The aim of this study was to investigate the spatial patterns and interactions of Astronium lecointei, Dinizia excelsa and Peltogyne paniculata, three dominant timber tree species in the Jamari National Forest, Rondônia, Brazilian Amazon. The Kernel estimator was used aiming to verify the possible influence of first-order factors on species distributions. Inhomogeneous K-functions were applied to analyze species spatial patterns and interactions by means of second-order factors. Univariate analyses revealed different scale-dependent spatial patterns for the species. Aggregation related to ecological characteristics, such as habitat preference and dispersal limitation, was verified for A. lecointei and P. paniculata. D. excelsa presented a random spatial pattern, explained by specific features of its establishment, such as the need for clearings due to light requirements. Interspecific associations were evidenced by bivariate analyses, in which spatial attraction of species resulted from the same preference for microhabitats and the repulsion was a result of niche segregation

Danos causados por bovinos em diferentes espécies arbóreas recomendadas para sistemas silvipastoris.

Três espécies arbóreas foram avaliadas quanto aos danos causados por bovinos em pastejo em um sistema silvipastoril implantado na região subtropical do Brasil. As espécies Schinus terebinthifolius (Raddi), Grevillea robusta (A. Cunn. ex R.Br) e Eucalyptus dunnii (Maiden), foram plantadas em linhas simples, arranjadas em 14 m x 3 m, para comporem um sistema agrossilvipastoril. Durante os primeiros três anos a área foi utilizada para produção de grãos em sistema de cultivo em aléias (silviagrícola). Após 41 meses do plantio das árvores, o gado foi introduzido pela primeira vez na área. Cinco classes de intensidade de danos foram estabelecidas: sem dano, baixa, média, alta e extrema. Os danos causados à casca do tronco das árvores no sistema foram maiores do que os causados às copas. As árvores de S. terebinthifolius foram as mais danificadas pelos bovinos. A manutenção de S. terebinthifolius em sistema silvipastoril não é recomendada pelo dano que o gado impõe às árvores

Physical and Antimicrobial Properties of Compression-Molded Cassava Starch-Chitosan Films for Meat Preservation

[EN] Cassava starch-chitosan films were obtained by melt bending and compression molding, using glycerol and polyethylene glycol as plasticizers. Both the starch/chitosan and the polymer/plasticizer ratios were varied in order to analyze their effect on the physical properties of the films. Additionally, the antimicrobial activity of 70:30 polymer:plasticizer films was tested in cold-stored pork meat slices as affected by chitosan content. All film components were thermally stable up to 200 A degrees C, which guaranteed their thermostability during film processing. Starch and chitosan had limited miscibility by melt blending, which resulted in heterogeneous film microstructure. Polyethylene glycol partially crystallized in the films, to a greater extent as the chitosan ratio increased, which limited its plasticizing effect. The films with the highest plasticizer ratio were more permeable to water vapor, less rigid, and less resistant to break. The variation in the chitosan content did not have a significant effect on water vapor permeability. As the chitosan proportion increased, the films became less stretchable, more rigid, and more resistant to break, with a more saturated yellowish color. The incorporation of the highest amount of chitosan in the films led to the reduction in coliforms and total aerobic counts of cold-stored pork meat slices, thus extending their shelf-life.The authors acknowledge the financial support provided by the Spanish Ministerio de Economia y Competividad (Projects AGL2013-42989-R and AGL2016-76699-R). Author Cristina Valencia-Sullca thanks the Peruvian Grant National Program (PRONABEC Grant).Valencia-Sullca, CE.; Atarés Huerta, LM.; Vargas, M.; Chiralt, A. (2018). Physical and Antimicrobial Properties of Compression-Molded Cassava Starch-Chitosan Films for Meat Preservation. Food and Bioprocess Technology. 11(7):1339-1349. https://doi.org/10.1007/s11947-018-2094-5S13391349117Alves, V. 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Modelagem da distribuição diamétrica de três espécies da região amazônica.

O manejo florestal deve estar apoiado no entendimento da dinâmica da floresta, a fim de garantir a melhor tomada de decisão. A estrutura diamétrica é uma ferramenta adequada, que fornece informações sobre uma determinada espécie ou para a floresta em geral. Assim, neste trabalho, foi avaliada a estrutura diamétrica de três espécies amazônicas: Bertholletia excelsa Bonpl. (Castanheira), Hevea brasiliensis (Willd. ex A.Juss.) Müll.Arg (Seringueira) e Swietenia macrophylla King (Mogno) na Floresta Estadual do Antimary, estado do Acre, Brasil. Também foram ajustadas funções de densidade de probabilidade mais comumente utilizadas para representar as distribuições diamétricas de espécies florestais. A espécie B. excelsa apresentou estrutura bimodal com uma grande amplitude diamétrica. H. brasiliensis apresentou distribuição unimodal assimétrica positiva. A baixa ocorrência de S. macrophylla na área de estudo não garante que a distribuição observada seja representativa. A estrutura diamétrica das três espécies é similar às reportadas em outros estudos. Na avaliação das funções de densidade probabilística, os modelos Normal e Weibull foram aderentes para as três espécies. Forest management should be based on understanding the forest dynamics in order to ensure better decision making. The diameter structure is an adequate tool, which provides information about a particular species or the forest in general. Thus, diameter structure of three Amazonian species were evaluated: Bertholletia excelsa Bonpl. (Castanheira), Hevea brasiliensis (Willd. Ex A.Juss.) Müll.Arg (Seringueira) and Swietenia macrophylla King (Mahogany) at Antimary State Forest, Acre State, Brazil. We also fitted probability density functions commonly used to represent the diameter distributions of forest species. B. excelsa presented bimodal structure with a great diameter amplitude. H. brasiliensis presented a unimodal distribution positively skewed. The low occurrence of S. macrophylla in the study area does not guarantee that the observed distribution is representative. The diameter structures of three species are similiar to those reported in other studies. In the evaluation of probabilistic density functions, Normal and Weibull models were adherent to the three species