Roberto Pequeno de Sousa

Densidade de plantio e rendimento de raízes de mandioca

In Mata Fresca, an area located on the border of the states of Rio Grande do Norte and Ceara, in Brazil, small farmers have a source of income from the production of cassava roots, using planting densities of around 5,000 plants ha -1 . This procedure might be helping to limit higher yields of the roots, since some studies have shown that it is possible to obtain higher yields of cassava using higher densities. The objective of this study was to evaluate the root yield and other characteristics of the cassava, as a response to planting density. The Vermelhinha cultivar was submitted to planting densities of from 5,000 to 21,000 plants ha -1 , at intervals of 2,000 plants ha -1 , in an experiment under irrigation. A completely randomized block design with four replications was used. The ideal planting densities in order to maximise leaf green matter, stems and branches, total roots, total marketable roots, number of marketable roots, marketable-root dry matter and stem dry matter, were 17,800; 17,077; 14,416; 13,594; 16,436; 12,361; and 18,149 plants ha -1 respectively. When adopting the planting density used by the farmers, a yield for marketable roots of 15,837 kg ha -1 was obtained. By using the optimal density as found in this work (13,594 plants ha -1 ), the yield was more than double that of the farmers. Increasing planting density reduced both the length of the marketable roots and the harvest index (the ratio of marketable-root dry matter to total plant dry matter).In Mata Fresca, an area located on the border of the states of Rio Grande do Norte and Ceara, in Brazil, small farmers have a source of income from the production of cassava roots, using planting densities of around 5,000 plants ha -1 . This procedure might be helping to limit higher yields of the roots, since some studies have shown that it is possible to obtain higher yields of cassava using higher densities. The objective of this study was to evaluate the root yield and other characteristics of the cassava, as a response to planting density. The Vermelhinha cultivar was submitted to planting densities of from 5,000 to 21,000 plants ha -1 , at intervals of 2,000 plants ha -1 , in an experiment under irrigation. A completely randomized block design with four replications was used. The ideal planting densities in order to maximise leaf green matter, stems and branches, total roots, total marketable roots, number of marketable roots, marketable-root dry matter and stem dry matter, were 17,800; 17,077; 14,416; 13,594; 16,436; 12,361; and 18,149 plants ha -1 respectively. When adopting the planting density used by the farmers, a yield for marketable roots of 15,837 kg ha -1 was obtained. By using the optimal density as found in this work (13,594 plants ha -1 ), the yield was more than double that of the farmers. Increasing planting density reduced both the length of the marketable roots and the harvest index (the ratio of marketable-root dry matter to total plant dry matter).

Tamanho e forma de parcelas para experimentos com girassol

Na experimentacao agricola, a utilizacao do tamanho e da forma adequada de parcela sao tecnicas experimentais importantes para aumentar a precisao do experimento. Assim, objetivou-se nesse trabalho determinar o tamanho e forma adequada de parcela para experimentacao em campo com girassol. Para isso, o experimento foi conduzido em blocos completos casualizados com 14 cultivares de girassol em 10 repeticoes. As parcelas foram constituidas de quatro fileiras de seis metros de comprimento, espacadas de 0,7 m e 0,3 m entre plantas. A area util da parcela (7,56 m2), composta das duas fileiras centrais, foi dividida em 12 unidades basicas, cada uma constituida por tres plantas na fileira (0,63 m2), obtendo-se o rendimento de graos de girassol. O tamanho conveniente da parcela experimental foi estimado pelo metodo de Hatheway e a sua forma adequada foi determinada pelo metodo da informacao relativa. O metodo de Hatheway permitiu estimar diversos tamanhos convenientes de parcelas, muitos de tamanhos aplicaveis para experimentos de avaliacao de cultivares de girassol. Parcela no formato retangular 1 x 6 (fileira com dezoito plantas e 3,78 m2 de area util), foi considerada a forma adequada para avaliacao do rendimento de graos de cultivares de girassol e, tambem, foi menor que o tamanho geralmente indicado nas pesquisas com a cultura do girassol.

Tamanho ótimo da parcela para experimentação com girassol

The aim of this study was to determine a suitable plot size for field experiments with the sunflower. An experiment was carried out in a randomised complete block design with 14 sunflower cultivars and 10 replications. The plots consisted of four rows, six metres in length, spaced 0.7 m apart with 0.3 m between plants. The working area of the plot (7.56 m 2 ), consisting of the two central rows, was divided into 12 basic units, each consisting of three plants per row (0.63 m 2 ), from where the yield of the sunflower seeds was obtained. Suitable plot size was estimated using the intraclass correlation coefficient method. The detectable difference between treatments was also estimated (d). The optimum plot size for the evaluation of grain yield in the sunflower was 2.52 m 2 (working area), considering a boundary of one row on each side. Greater gains in experimental precision (16%) with increases in plot size, occurred up to eight basic units (5.04 m 2 ) using seven replications. Increasing the number of replications and the plot size was more efficient

Probabilidades para pressão atmosférica no município de Mossoró-RN

Objetivou-se elaborar uma tabela de probabilidades da ocorrencia de valores mensais da pressao atmosferica em milibar, para Mossoro, RN, Brasil, a partir dos registros diarios das pressoes atmosfericas obtidas na Estacao Meteorologica da Universidade Federal Rural do Semi-Arido em Mossoro, RN, referentes a uma serie historica de trinta e oito anos (1970-2007). A pressao atmosferica mensal em milibar foi estimada utilizando o modelo da distribuicao densidade de probabilidade normal, para os niveis de 1% a 95% de probabilidade. Tendo-se em conta os resultados dos testes de aderencia a 10% de probabilidade e utilizando-se o Logaritmo da Maxima Verossimilhanca, pode-se concluir pela adequabilidade do processo de construcao da Tabela de probabilidades, e que esta representa importante subsidio no planejamento das atividades agropecuarias na regiao, tirando o maximo proveito dos seus beneficios e evitando os seus efeitos danosos. Probability table for atmospheric pressure in city of Mossoro-RN Abstract : The aim of this study was to develop a table of probabilities of occurrence of monthly values of atmospheric pressure in millibars, to Natal, RN, Brazil, from the daily records of atmospheric pressures obtained at the Meteorological Station of the Federal Rural University of the Semi-Arid in Mossley, RN, referring to a historical series thirty-eight-years (1970-2007). The atmospheric pressure in millibars monthly was estimated using the model distribution normal probability density to levels of 1% to 95% probability. Try into account the results of the compliance tests at 10% probability and using the logarithm of Maximum Likelihood, we can conclude the suitability of the construction of the table of probabilities, and that this is an important benefit in the planning of agricultural activities in the region, making the most its benefits and avoid its harmful effects.

Avaliação biométrica de caracteres do melão de São Caetano (Momordica charantia L)

The melon from Sao Caetano is a climbing plant, originally from India and South East India and is found in the savanna biome. This study aimed to evaluate the biometric fruit and the number of seeds per fruit of the melon Sao Caetano. The fruits were collected inside a native vegetation area of the campus at the Universidade Federal Rural do Semi-Arido (UFERSA), located in the city of Mossoro, RN. They were then taken to the laboratory of crop science, for the determination of the following characteristics: length, diameter and fruit weight as well as number of seeds per fruit. The descriptive and graphical analyzes were performed by using the statistical package R -project software. The length and diameter variables exhibited a low amplitude variation and a good value for the coefficient of variation. However, the fruit weight and number of seeds per fruit showed a high amplitude variation. There was a high degree of symmetry and a flattened distribution for all traits evaluated in this study. It was also found significant positive simple linear correlation between the length and diameter, and no significant difference between the weight and number of seeds per fruit. The data related to all features of the Sao Caetano melon fruit evaluated in this study were adjusted to normal distribution of probability which allows the performance of interferences with statistical basis.