Desenvolvimento das plantas, ocorrência de insetos, produção e conservação de frutos de goiabeiras sob adubações orgânica e mineral / Plant development, insect incidence, fruit yield and conservation of guava fruits under organic and mineral fertilization

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

The influence of mineral fertilizers and organic compost on the development of guava trees, fruit yield, insect incidence and fruit post-harvest conservation was evaluated. Also, the effects of different doses of mineral fertilization (ammonium sulphate and potassium chloride) and organic compost was studied by supplying proportions of the recommended dose (one third, total and the triple) of nutrients for the cultivation of guava. The experiment was established in the Experimental Orchard of the Federal University of Viçosa, using plants of cultivar Pedro Sato, in a randomized block design, using a [(2x3)+1] factorial scheme, with seven treatments. Data were examined by variance analysis and by unfolding of the interaction to study the dose proportions within each type of fertilizer, through regression analysis. The regression coefficients were tested by the t-test, and F-test was used to compare the means of fertilizers within each proportion of dose, at 5% significance. The F-test was also used to verify the equality of the regression models for fresh mass losses of fruits as a function of storage time, in the study of post-harvest conservation. Plants fertilized with organic compost and with mineral fertilizer in equivalent doses showed no differences in vegetative development. Doses of mineral fertilizer 1.65 time above the recommended dose for the culture damaged plant development, whereas the dose of organic compost provided linear increase of the development and the triple dose was not shown harmful. Fruit yield was similar for plants fertilized with organic compost and mineral fertilizer. The organic compost gave smaller fruit yield only when one third of the fertilizer dose was used. Doses of mineral fertilizer 1.82 time above the recommended doses for the culture affected fruit yield negatively. The increase in dose proportions in the form of organic compost provided linear increase in yield and no harmful effect was found for the triple dose. The occurrence of thrips, aphids and natural enemies and total phytophagous insects did not differ with the sources and doses of fertilizer applied to the plants. Guava trees fertilized with the triple dose of mineral fertilizer sheltered larger numbers of sprout caterpillars than those that received the equivalent dose of organic compost. Damages caused by Triozoida sp. were not affected by the type of fertilizer, but responded to the proportions of the applied mineral fertilizer and organic compost doses. Larger sizes of damages were found with 1.83 time above the recommended dose of mineral fertilizer and with 1.66 time above the dose of organic compost recommended for the culture. Greater fresh mass loss was found in fruits from plants with mineral fertilization than in fruits from plants fertilized with organic compound. The results showed that organic compost has high potential to be used as the only source of fertilization in guava culture.

ASSUNTO(S)

fruit quality goiaba psidium guajava fitotecnia organic agriculture psidium guajava guava qualidade de frutos fruticultura orgânica

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