Daniel Pereira Guimarães

Análise de crescimento de girassol em Latossolo com diferentes níveis de saturação por bases no Cerrado

Growth analysis of sunflower in a Cerrado Oxisol with different levels of basis saturation Abstract - In order to study the growth cycle of five sunflower cultivars, four experiments were carried out under four levels of basis saturation (18%, 35%, 56% and 77%), obtained with the application of dolomitic limestone in an acidic Red Latosol, clay texture (Tipic Haplusthox). Weekly growth data were fitted using the Logistic, three parameters Weibull and four parameters Generalized Logistic (a special case of Richards function) functions. Among the models used, the Logistic function obtained was the best growth data fitting. The NLIN procedure of SAS statistical package was used for fitting the data through the interactive process of DUD method. Cultivars were grouped according to final size and growth rates by a cluster analysis using the complete linkage method and by the Euclidian distance. Sunflowers growth reduced in all cultivars at 18% basis saturation level. At 35% basis satu- ration level, the best results were achieved for cultivar M734. In other instances, the best growth results were obtained between 56% and 77%. For cultivars EMBRAPA 122 and M738, growth rates were reduced when basis saturation was increased to 77%. The cultivar EMBRAPA 122 presented initial higher growth rate and lower plant height at the end of vegetative cycle.

Eficiência das funções weibull e hiperbólica para descrição de distribuições diamétricas de povoamentos de Tectona grandis

The Weibull probability density functions and Hyperbolic were compared by efficiency for describing the diameter structure of teak stands (Tectona grandis L. f.) undergoing thinning. These functions with three and four parameters were adjusted using data from 98 permanent plots and rectangular (490 m²), located in thinning stand of Tectona grandis in the Brazilian state of Mato Grosso, being measured for 10 years. Adjustments were made by Maximum Likelihood and adherence was assessed by Kolmogorov-Smirnorv test (a = 1%) and also compared to the residual squares sum (RSS) of the various adjustments. All of the functions presented adherence to data by the Kolmogorov-Smirnorv test (a = 1%). The hyperbolic function had lower squares sum of waste and lower values for the adherence test. It was concluded that the hyperbolic function was more efficient to describe the diameter structure of the studied stands.

Ocorrência de queima das folhas causada por Phomopsis sp. em Aroeira no Distrito Federal

The fungus Phomopsis sp. was consistently isolated from blighted leaves of aroeira trees (Myracrodruon urundeuva) in Federal District, Brazil, in 1999. Pathogenicity tests on aroeira seedlings under greenhouse conditions have confirmed the fungus as the causal organism of the disease. Symptoms of leaf blight appeared six to eight days after inoculation. The a conidia of the pathogen were 5,3-7,8 x 2,0-2,7 µm, hyaline, ellipsoid to ovoid, and the b conidia were 17,5-.27,5 x 0,5 µm, filiform, mostly curved and hyaline.

Um modelo de passo invariante baseado na função de Gompertz para prognose do crescimento

A step invariant model based on Gompertzs function is presented. Model adjustment was done on broilers and Eucalyptus grandis growth data. The proposed model presents the form Pf = Pa.exp(β 0 .S β2 (exp(β 1 .Ia))-(exp(β 1 .If))), where Pf refers to the future estimated yield at age (If) based on yield (Pa) observed at present age (Ia). S means the introduction of a new variable to the model, being used as binarian variable to indicate male and female broilers and as a site quality for eucalypt. The main advantages of using the proposed model resides in the compatibility of results, assured by the step invariant characteristics, individuals projections and analysis of errors based on the prognosis intervals.

INTERAÇÃO DE FATORES BIOFÍSICOS E ANTRÓPICOS COM A DIVERSIDADE FLORÍSTICA NA INDICAÇÃO DE ÁREAS PARA CONSERVAÇÃO DO BIOMA CAATINGA

A diversidade floristica da caatinga foi relacionada com fatores biofisicos e antropicos para indicacao de areas para conservacao. Utilizou-se a analise multicriterio para indicar regioes favoraveis a maior diversidade, por meio de fatores biofisicos, e regioes com menor pressao antropica, a partir de variaveis socio-economicas extraidas do censo agropecuario. Os resultados foram comparados com inventarios floristicos, fitossociologicos e de biomassa, no qual alguns fatores apresentaram relacoes significativas com a diversidade floristica da caatinga. As areas indicadas por estes fatores foram analisadas conjuntamente com fatores antropicos, indicando-se areas potenciais para conservacao no Bioma Caatinga.