Dione Pereira Cardoso

Plantas de cobertura no controle das perdas de solo, água e nutrientes por erosão hídrica

R ESU M O Plantas com alto indice de cobertura e elevada produtividade de fitomassa propiciam melhor protecao ao solo, amortecendo o impacto das gotas de chuva sobre a superficie do solo reduzindo, consequentemente, os processos erosivos. Objetivou-se avaliar a influencia das plantas de cobertura e dos espacamentos de plantio no controle das perdas de solo, agua e nutrientes por erosao hidrica, visando a conservacao do solo. O experimento foi conduzido em um Argissolo Vermelho-Amarelo, cujos tratamentos foram definidos por tres especies de plantas de cobertura: crotalaria juncea, feijao-deporco e milheto e com dois espacamentos entrelinhas (0,25 e 0,50 m). Para a quantificacao das perdas de solo, agua e nutrientes, utilizaram-se parcelas de 4 x 12 m em que a maior dimensao obedeceu ao sentido do declive. Nos meses de dezembro e janeiro ocorrem os maiores valores de erosividade requerendo, neste periodo, melhor cobertura da superficie do solo. O feijao-de-porco foi a especie que apresentou maior potencial no controle dos processos erosivos; quanto ao espacamento a melhor protecao do solo para todas as culturas foi obtida no espacamento de 0,25 m, propiciando menores perdas de solo, agua e nutrientes. Palavras-chave: crotalaria juncea, feijao-de-porco e milheto

Controle fitopatológico do Fusarium subglutinans pelo óleo essencial do capim-citronela (Cymbopogon nardus L.) e do composto citronelal

This study aimed to evaluate the fungitoxic effect of the essential oil of citronella grass and its major constituent citronellal on the inhibition of mycelial pathogen Fusarium subglutinans, the causal agent of Fusarium culture of pineapple (Ananas comosus). To evaluate the effect of essential oil in the mycelial growth of the fungus were used six rates (0, 5, 10, 15, 20 and 25 mL) of oil that were distributed on the surface of PDA medium (potato dextrose agar) before subculturing of the fungus. Mycelial growth was measured after 48 h of the experiment and five times of assessment (2, 4, 6, 8 and 10 days after subculturing). The results indicated that the essential oil of citronella grass showed higher inhibitory effect of mycelial growth of the fungus F. subglutinans than compound citronellal. In all rates used of the essential oil gave lower growth rate than the mycelial citronellal.

Composição e fungitoxicidade do óleo essencial de capim citronela em função da adubação orgânica

The objective of this work was to evaluate the influence of organic fertilization on the content and composition of the essential oil of citronella grass (Cymbopogon nardus), as well as to assess the fungitoxicity of this oil to the mycelial growth of the fungi Didymella bryoniae, Colletotrichum gloeosporioides, and Amphobotrys ricini. The extraction of the essential oil was done by hydrodistillation in plants cultivated with four doses of organic fertilizer (0, 3, 6, and 9 kg matured cattle manure per hole), and the identification of the chemical compounds was done by gas chromatography/mass spectroscopy. To evaluate the inhibition of mycelial growth, the experiment was installed in a completely randomized design in a factorial arrangement. Seven aliquots of essential oil were tested (0, 5, 10, 15, 20, 25, and 30 µL) in five evaluating times, with four replicates. The contents of the essencial oil in citronella grass were note affected by organic fertilization, and the oil includes 24 chemical compounds, among these monoterpenes and sesquiterpenes, with higher concentrations of the compounds citronellal, β-citronellol, geraniol, and elemol. The essential oil of citronella grass has higher inhibition effect on Amphobotrys ricini, when compared to the fungi Didymella bryoniae e Colletotrichum gloeosporioides.

Teor e composição do óleo essencial de quatro acessos e duas cultivares de manjericão (Ocimum basilicum L.)

The objective of this study was to evaluate the essential oil chemical composition and content of four wild accessions of basil (Ocimum basilicum L.), from different geographical regions, and two commercial cultivars grown under the same edaphoclimatic conditions. The seeds of the accessions were collected in the municipality of Gurupi, state of Tocantins (GUR), and Monte Alegre, state ofGoias (MAL, MVE and FPS), and the seeds of the commercial cultivar of purple basil (MR) were acquired in the Gurupi market and the seeds of the commercial cultivar Maria Bonita (MB) were provided by the Garden of Medicinal Plants of the Federal University of Lavras. The seeds were planted in pots with a capacity of ten liters using as substrate soil from earth works and cattle manure in the proportion of 2:1. The essential oil was obtained by hydrodistillation using a Clevenger-type apparatus, and the identification and the relative percentage of the compounds of the essential oil were performed by Gas Chromatography coupled to Mass Spectrometry Detector. Thirty-nine compounds were identified in the essential oils obtained, which were divided into monoterpenes, sesquiterpenes and phenylpropanoids. In the cultivars MB and MR, the major compound was linalool, and in the wild accessions (MAL, GUR, FPS and MVE) it was the (E)-methyl cinnamate. The highest content of essential oil was obtained from the cultivar Maria Bonita (3.77%).

CAPACIDADE COMBINATÓRIA DE MILHO VISANDO À PRODUÇÃO DE SILAGEM

Although corn silage be sufficiently known, the availability of these materials in the market is low, demonstrating that specific breeding programs in this area are scarce. Thus, the aim of this study was to determine the predominant type of gene action in controlling the characteristics and estimate general (GCA) and specific combining (CEC) among commercial corn hybrids aimed at producing corn. The eight hybrids and 56 hybrid combinations were evaluated in crop year 2011/2012, in the town of Gurupi, located in southern Tocantins. The experimental design used was 8 x 8 lattice with two replications and analyzed three characteristics of commercial interest for the production of corn for silage. The hybrid combinations responded differently to combinations of capabilities, when subjected to conditions of low and high phosphorus availability, as evidenced by the significant effects of the interactions. This indicates that the selection should be performed in environments where they will be used. We conclude therefore that the hybrid P 30F53Y had higher concentration of favorable alleles in enhancing the features and PMS PMV being more suitable in the formation of new hybrids, combinations AG in 2040 x TRUCK, TRUCK AG 8060 and AG 1051 x x IMPACT was higher heterotic effect, these being the most suitable hybrids for silage. The dominant gene in this analysis is due to additive effects.

Weed interference on radish crop

This study aimed to evaluate the effect of different periods of weed coexistence with radish culture. The experiment was carried out in Gurupi-TO, in a randomized block design with four replications. The treatments consisted of 6 increasing periods of coexistence with weeds, considered from the rough, valued at five seasons assessments (5, 10, 15, 21, and 30 DAE). Dry stem masses were evaluated, leaf and total shoot, leaf area, root diameter and fresh root biomass. The data were submitted to analysis of variance to compare means by the Scott and Knott test. It was observed that longer periods of coexistence with weeds caused a reduction of 72.1% in the production of fresh weight root culture. Living with weeds up to 15 days after emergence did not significantly alter the radish root diameter in this study.

Evaluation of rainfall coefficient-Rc

Abstract The aimed was to evaluate the precipitation by the coefficient of rain, the payback period and the probability of occurrence, in order to implement appropriate conservation measures aimed at the sustainable development of agricultural activity in the north of the Espirito Santo. The rainfall data were provided by the National Water Agency - ANA. These were obtained in Climatological stations called Itauninhas, Barra Nova, Sao Joao da Cachoeira Grande and Boca da Vala in the municipality of Sao Mateus in northern Espirito Santo. It was determined the rainfall coefficient (Rc), the return period and the probability of occurrence. The maximum values of total precipitation and maximum rainfall coefficient amounted to 11183.4 mm, 7778.4 mm, 5885.3 mm and 3528.6 mm Itauninhas, Barra Nova, Sao Joao da Cachoeira Grande and Boca da Vala, respectively. The maximum values for the rainfall coefficient for Itauninhas, Barra Nova, Sao Joao da Cachoeira Grande and Boca da Vala were 163.3 mm, 193.8 mm, 142.7 mm and 110.5 mm, respectively. Return periods for the most rainfall coefficient value were 67 years (Itauninhas), 45 (Barra Nova), 35 (Sao Joao da Cachoeira Grande) and 23 years (Boca da Vala). For climatological stations Itauninhas, Barra Nova, Sao Joao da Cachoeira Grande and Boca da Vala, the precipitation values are higher than the rainfall coefficient, for the months January to December, for the respective time series. The variation of the probability of occurrence is 1.5% to 4.35%, Itauninhas and Boca da Vala, respectively.