Eradication of eucalyptus sprouts after chemical weeding over time in State of Bahia, Brazil.

This study evaluated the eradication of eucalyptus sprouts after chemical weeding using a diagrammatic scale over time. The research was conducted in fields planted with eucalyptus in forest reform areas, in Itabela, Bahia, Brazil, during the pre-planting herbicide application. The application was carried out in five fields, which were considered as sample units of the different treatments. The effectiveness of chemical weeding for controlling sprout growth was evaluated in fifty plants per treatment, randomly selected in three periods after application. The plants were evaluated visually using a diagrammatic scale to assign scores between 1 and 5 to the sprout control percentage. After the visual evaluations, the frequency distribution of the sprouting percentage for each score was calculated. Subsequently, the scores were submitted to a clustering analysis by the Ward method, to evaluate the relationship between different fields and periods for each treatment in homogeneous clusters. The results showed that treatments only controlled the sprouts in the short term, without providing effective eradication. The diagrammatic scoring scale allowed evaluating the vegetative vigor of the eucalyptus sprouts, generating interpretable information on the different evaluated treatments, making it a useful tool for managing silvicultural treatments and evaluating the application efficacy of phytosanitary products.

Spatial-temporal variability of rainfall and mean air temperature for the state of Bahia, Brazil.

The aim of this study was to evaluate spatial behavior and temporal stability of rainfall and mean air temperature in the state of Bahia, using historical series from 1975 to 2011 and 1961 to 2009, respectively. The analyses were performed considering the accumulated variables of each month of the historical series. The accumulated monthly totals were divided by the number of years of observation, obtaining the monthly average values ​​of rainfall and air temperature for each measurement point. The data were submitted to descriptive statistical analysis and linear correlation studies. Geostatistical analysis was used to verify the existence and quantify spatial dependence between the values of the studied variables. In addition, the maps were submitted to algebra operations, calculating the spatial difference between months for each of the variables. For that purpose, the difference between one month and its subsequent period was calculated in order to establish the behavior of the variables over time. Climatic variables showed a close relationship between each other, demonstrating their spatial and temporal variation, which is mainly dependent on the seasons of the year. The rainfall and mean air temperature variables showed stable spatial behavior and high temporal stability between subsequent months.