Daiane de Cinque Mariano

Adubação fosfatada na cultura do milho no nordeste paraense

In Brazil, the maize crop has high production volume, and the State of Para has the potential to become major center for grain production. However, it consists of tropical soils, which are acidic and low phosphorus availability. The aims of this study was to evaluate the growth and productivity of maize plants exposed to different rates of phosphorus in typical dystrophic Yellow Latosol in Capitao Poco city, Northeastern Para State, in 2011. In the experimental area, soil correction was performed by liming, increasing the base saturation to 60%. The experimental design was a randomized block with four replicates, in which the treatments were: 0; 45; 90; 135 and 180 kg ha-1 of P2O5 applied at sowing, using triple superphosphate source (46% P2O5). The variables: plant height, stem diameter, number of leaves and number of ears showed a better adjustment of quadratic equation to application of P2O5 in sowing furrow with maximum technical efficiency obtained at rates of 142.1 kg ha-1; 114.62 kg ha-1; 130.59 kg ha-1 and 145 kg ha-1 of P2O5, respectively. The application of 179.87 kg ha-1 of v in corn crop (BR 5102 variety) in a typical dystrophic Yellow Latosol promoted yield of 6.58 t ha-1 of grains under the soil and climatic conditions of Capitao Poco region.

LEVANTAMENTO FLORÍSTICO DO COMPONENTE ARBUSTIVO-ARBÓREO DA VEGETAÇÃO CILIAR DE FRAGMENTO NO RIO PARAUAPEBAS

RESUMO: As atividades relacionadas a mineracao sao causadoras de enormes alteracoes na estrutura e na dinâmica da paisagem, sendo fundamentais estudos da diversidade floristica para elaboracao de estrategias de conservacao da biodiversidade. O objetivo do estudo foi analisar a composicao floristica em floresta de varzea, proximo a ambiente impactado por atividades mineradoras, localizada ao longo do rio Parauapebas. Foram instaladas 13 parcelas fixas de 10 x 10 m (10 m2), alocadas de forma sistematica na area de mata ciliar, ao longo da margem do rio Parauapebas, municipio de Parauapebas, PA. Por meio dos resultados do experimento foram identificadas 23 familias distribuidas em 18 generos e 30 especies. As familias com maior numero de especies foram Fabaceae (11), Malvaceae (3) e Rutaceae (2). O genero com maior riqueza em especies foi Inga sp., com 3 especies diferentes, respectivamente. A familia Fabaceae representou 32% das especies coletadas, Malvaceae 10% e Rutaceae 6%. Das especies amostradas, uma foi exotica, representada pelo Citrus limon (L.) Osbeck (limao-galego) e o individuo com maior representatividade foi Sterculia chicha A. St. -Hil., presente na maioria das parcelas. Apesar do fragmento encontrar-se ameacado por acoes antropicas, a variedade floristica no local apresenta-se bastante diversificada, com especies pioneiras, secundarias e climax. PALAVRAS-CHAVE: Composicao floristica, Flora amazonica, Riqueza.

Management Practices for Insect Resistance in Bt Maize

The failure to reduce the population of a phytophagous species recognized as a key pest in a given situation usually occurs by not using the principles of Integrated Pest Manage‐ ment (IPM). The control of insect pests in agriculture has been done mainly through the application of chemical insecticides. However, chemical insecticides has lost effectiveness due to the selection of populations of resistant insects and cause adverse environmental effects. The main resistance management programs (IRM) strategy is the use of ‘high dose/refuge’, which involves the use of high dose of Bt protein in plants, promoting high mortality of heterozygotes associated with the planting of refuge, ie, a proportion of the crop in which it must be planted a non-Bt variety, allowing the survival of susceptible in‐ dividuals. The emergence of Bt crops is an important step between the tactics available for pest control in various crops such as maize, canola, cotton and, in the near future, soy‐ beans.