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da Silva P.M.C.,UFRR CCA | Neves L.C.,UFRR CCA | Bastos V.J.,UFRR CCA | Lima C.G.B.,UFRR POSAGRO | And 2 more authors.
Scientia Horticulturae | Year: 2016

The fruits were harvested for six consecutive years during the rainy season from a population native to a savannah environment, and they were analyzed at intervals of seven days after anthesis (DAA). Chemical analyses were conducted (pH, total acidity, soluble solids, total and reducing sugars, total and soluble pectin, polygalacturonase enzyme (PG) and pectin methyl esterase (PE) enzymes, phenolic compounds, vitamin C and antioxidant activity by the oxygen radical absorbance capacity (ORAC) and α, α-diphenyl-β-picrylhydrazyl (DPPH) methods), respiratory activity was determined, and physical evaluations were performed (diameter and fruit and pulp fresh weight). The experiment was conducted in a completely randomized design (CRD) with a regression analysis and model fitting using the statistical F-test at a 5% significance level. The results showed climacteric behavior of the fruit as well as significant antioxidant activity related to the presence of phenolic compounds and vitamin C. The harvesting time, according to the evaluated parameters, was determined to be the interval between 28 and 35 DAA. © 2016 Elsevier B.V. Source

Barros M.M.,UFRR | Araujo W.F.,DSEA UFRR | Neves L.T.B.C.,DFT UFRR | de Campos A.J.,UEG UnUCET | Tosin J.M.,Brazilian National Council for Scientific and Technological Development
Revista Brasileira de Engenharia Agricola e Ambiental | Year: 2012

The aim of this study was to evaluate the effect of different rates of nitrogen on production and quality of watermelon 'Crimson Sweet'. This research was conducted in the experimental area of the Federal University of Roraima, Boa Vista, from January to April 2010. The experimental design was in randomized blocks with 4 replications. The treatments consisted of 5 levels of nitrogen (50, 100, 150, 200 and 250 kg ha-1 N) applied as urea in a conventional manner. The results showed that the maximum commercial production was 40,428 kg ha-1 with 144.76 kg ha-1 N. Regarding the fruit quality, the pH was not affected by treatments, showing mean value of 5.34. The length/diameter ratio and bark thickness also were not influenced by the treatments, while the firmness, content of soluble solids (SS), titratable acidity (TA), content of sugars (reducing, non reducing and total), the ascorbic acid content and the ratio SS/TA were not influenced by N levels. Source

The experiment was carried out in Piracicaba, SP, in order to evaluate the effects of different carbon dioxide levels applied with irrigation water, associated or not to the mulch plastic, on yield of summer squash. The experimental design was in random blocks in split plot design, with the factor levels of CO2 in the plot and the mulch plastic in split-plot. The treatments constituted on the following levels: 0; 59; 148 and 247 kg ha-1 of CO2. The irrigation was scheduled daily based on a tank class A, using a drip irrigation system. The leaf area, the number of fruit and the yield were evaluated. The levels of CO2 and mulch plastic influenced the leaf area; consequently, it provided increment in the number of fruit and yield of summer squash. The best yield of 15, 433 kg ha-1was obtained by 58.6 kg ha-1 of CO2 with the plastic mulch. Source

Melo V.F.,Federal University of Roraima | Francelino M.R.,Federal Rural University of Rio de Janeiro | Uchoa S.C.P.,POSAGRO UFRR | Salamene S.,Institute Floresta | dos Santos C.S.V.,UFRR
Revista Brasileira de Ciencia do Solo | Year: 2010

In Roraima, the spatial distribution of indigenous peoples indicates a background of constant search for soils capable of sustaining shift cultivation. This study aimed to establish a relationship between the understanding of soil by the Yanomami tribe from the mid-Catrimani river region and the Brazilian System of Soil Classification and evaluate the type of agricultural land use according to soil fertility tests, in two steps. The first consisted of visiting eight Indian communities to collect soil samples at 21 sites with different types of agriculture and forests, both from profile soil (depth 0-1.50 m) and pits (depth 0-0.1 m and 0.1-0.3 m) for laboratory analysis. The second step was a workshop addressing the shift cultivation systems (duration 20 h). The discussion focused on the understanding of the environment (Urihi) and agricultural production systems, and on the importance of the correct use of knowledge of the soil and its fertility. Soils are named according to their morphology and position in the landscape by the Yanomami. The choice of agricultural areas is based on these features, aside from the organic matter content and the presence of earthworms. Agricultural practices comprise clearing and burning of the native forest immediately before planting a set of separate crops. The soils described in the area were classified according to the Brazilian taxonomic system as follows: Red Yellow Argisol (Maxita a uuxi wake axi), Yellow Argisol (Maxita a axi) Yellow Latosol (Maxita a axi) and Plintosol (Maxita a axi a maaxipé). Slashing and burning initially increases exchangeable Ca, K and available P due to the contribution of the ashes, which allows an agricultural exploitation of these areas for a maximum period of three years. Source

Welter M.K.,Agronomia CCA UFRR | Melo V.F.,UFRR | Bruckner C.H.,Campus Universitario | de Goes H.T.P.,Brazilian National Council for Scientific and Technological Development | Chagas E.A.,Embrapa Roraima
Revista Brasileira de Fruticultura | Year: 2011

The seedling production of native fruits is an important step towards the preservation of species, commercial exploitation and sustainable employment generation. In this context, alternative fertilizers, such as rock dust, provide obtaining a substrate with higher fertility, nutrient-rich, with reduced costs in manpower and replacement of fertilization. The objective in the present research was to evaluate the initial development of camu-camu seedlings (Myrciaria dubia H.B.K. McVaugh) in function of levels of crushed basalt. The experiment was carried out in a greenhouse, at CCA/UFRR. The experimental designed was completely randomized with eight treatments and five repetitions in factorial scheme (5x2+1), being five levels of crushed basalt (0, 0.42, 1.04, 2.08, 4.17 and 8.33 g kg-1), two particle size (0.05 mm and 0.10 mm φ). Vases of polyethylene of 14L of capacity were the experimental units, and the soil was a Distrofic Yellow Latosol. The incubation period of the soil in vases was for 120 days and after that period the seedlings were transplanted to vases. Six months after the transplant the height, diameter of plant, branches number, and aerial part and root dry biomass of seedlings were determined. From this data the morphologic indexes were calculated. The Treatments without crushed basalt (0 g kg-1) and the levels 0.42 g kg-1 produced seedlings of lower quality in both granulometry analyzed. The better development of seedlings of camu-camu was obtained using 4.17 e 8.33 g kg-1 of crushed basalt with 0.05 granulometry. Source

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