Wellington Farias Araújo

Produção e qualidade da melancia submetida a adubação nitrogenada

ABSTRACT The aim of this study was to evaluate the effect of different rates of nitrogen on production and quality ofwatermelon ‘Crimson Sweet’. This research was conducted in the experimental area of the FederalUniversity of Roraima, Boa Vista, from January to April 2010. The experimental design was in randomizedblocks with 4 replications. The treatments consisted of 5 levels of nitrogen (50, 100, 150, 200 and 250kg ha -1 N) applied as urea in a conventional manner. The results showed that the maximum commercialproduction was 40,428 kg ha -1 with 144.76 kg ha N. Regarding the fruit quality, the pH was not affectedby treatments, showing mean value of 5.34. The length/diameter ratio and bark thickness also were notinfluenced 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 werenot influenced by N levels. Key words: Citrullus lanatus , postharvest, characterization, productivity

Irrigação e adubação nitrogenada em milho

The aim of this work was to study the effects of water and nitrogen application on corn crop components (BR 201) and productivity in the cerrado area of Roraima, Brazil. The statistical analysis consisted of a 4 X 4 randomized block design, using split plots with 16 treatments and 4 replications. The four water depths used were 392.6; 337.6; 282.6 and 227.6mm and the four nitrogen rates were 0; 50; 100 and 150 kg ha-1. The water depth used influenced the height of the corn plant. Irrigation and nitrogen levels influenced the mass of 100 seeds, the number of ears per hectare and the grain productivity. The seed N levels were linearly influenced by the nitrogen fertilization.

Irrigation management of muskmelon using the class A pan evaporation

An experiment was carried out to evaluate the effects of irrigation levels, based on fractions of the class A pan evaporation, on yield and the chemical and physical characteristics of muskmelon cultivar Bonus no 2 grown under plastic house conditions and drip irrigation in Roraima State, Brazil. The experimental design was randomized blocks with six treatments (0.20; 0.40; 0.60; 0.80; 1.00 and 1.20% of ECA) and four replications. The results of yield showed a linear response of the applied irrigation levels, with values of 4 kg m-2. All others physical characteristics, except for pulp firmness, showed a linear response to irrigation treatments. Total soluble solids showed a linear decreasing response with respect to the irrigation levels with values between 10.4 and 11.7o Brix, while fruit pH was not affected by treatments, averaging 6.74.

Influência do CO2 via água de irrigação e da cobertura plástica no solo na Abobrinha

Resumo - O experimento foi realizado em Piracicaba, SP, com o objetivo de avaliar os efeitos de doses de CO 2 aplicadas via agua de irrigacao associadas ou nao a cobertura plastica do solo na producao da abobrinha cultivada em cam po aberto. O delineamento foi em blocos completos ao acaso, em esquema de parcelas subdivididas, com o fator CO 2 na parcela e o fator cobertura nas subparcelas. Os tratamentos foram constituidos das seguintes doses de CO 2 aplicados via agua de irrigacao: 0; 59; 148 e 274 kg ha -1 de CO 2 . O sistema de irrigacao foi por gotejamento com reposicao diar ia de agua, baseada no tanque classe A. As variaveis analisadas foram: area foliar por planta (cm 2 ), numero de frutos por planta e produtividade (kg ha -1 ). A interacao entre os fatores doses de CO 2 e a co bertura do solo apresentaram efeito significativo sobre as variaveis analisadas. A maior produtividade de abobrinha foi de 15.433 kg ha -1 obtida com o uso de 58,6 kg ha -1 de CO 2 associado a cobertura plastica. Palavras-chave - Cucurbita pepo L.. Dioxido de carbono. Irrigacao por gotejamento. Mulch.

Efeito de sistemas de preparo do solo e métodos de irrigação sobre a cultura do caupi em várzeas em Roraima

Two experiments were carried out during December, 1995 to March, 1996 and from December, 1996 to March, 1997 at the Experimental Station of Bom Intento, Boa Vista, RR. The objective was to evaluate the effects of different irrigation systems and tillage on soil bulk density and cowpea crop on wetland soils. The experimental design consisted of a split plot in a randomized block design, with four replications. The cowpea cv. Sempre Verde was tested under furrow and sprinkler irrigation in two soil tillage systems, as follows: disc harrow + leveling disc harrow and plough grid + leveller grid + moldboard plough. There were no significant differences among treatments with respect to production components and the crop yield. The mean grain yield was 1,853 kg ha-1. The soil bulk density after tillage with plough grid + leveller grid was significantly (p < 0.05) increased in comparison with the other tillage practices.

Respiratory Behavior and Preservation of Mana Cubiu Stored at Different Temperatures of Refrigeration

FCA/UNESP-Faculdade de Ciencias Agronomicas Universidade Estadual Paulista Julio de Mesquita Filho Fazenda Experimental Lageado, 280, C.P237

Cultivo in vitro de plântulas de abacaxizeiro com uso de filtros, ventilação artificial e sacarose

An alternative to the production of quality seedlings is the use of in-vitro systems of propagation. However, the conventional in-vitro environment is different from the external environment, and is often the reason for physiological and morphological disorders in the plant. To this effect, the aim of this study was to evaluate the use of filters and artificial ventilation to increase air exchange between the flask and environment, and adjust the concentration of sucrose in the culture medium for a better development of the photosynthetic apparatus, and stimulate the growth of pineapple plants in vitro. The experimental design was completely randomised in a 3 x 3 factorial scheme with nine replications. The factors under study consisted of three concentrations of sucrose (0, 15, and 30 g L-1) and three methods for ventilating the flask (unfiltered flask with no ventilation, filtered flask with no ventilation, and filtered flask with ventilation). The use of unfiltered flasks with no ventilation and 15 g L-1 of added sucrose, resulted in greater growth of the pineapple plants in vitro. The use of filtered flasks with ventilation promotes an increase in the levels of chlorophyll-a, chlorophyll-b, and total chlorophyll, as well as improvements in the system of photosynthesis of the pineapple seedlings.