Produção de biomassa, teor e exportação de macronutrientes em plantas de repolho em função de doses de nitrogênio e de espaçamentos

Abstract

RESUMOAvaliou-se o efeito de três espaçamentos (80x30, 60x30 e 40x30 cm) e de cinco doses de N (0, 75, 150, 225 e 300 kg ha -1 ) sobre a produção de massa seca (MS), teores e exportação de macronutrientes na cultura do repolho. Conduziu-se o experimento a campo, na Horta de Pesquisas do Departamento de Fitotecnia da Universidade Federal de Viçosa, no período de 23/09 a 20/12/2002. Utilizouse o esquema parcelas subdivididas, delineamento inteiramente casualizado, com quatro repetições, sendo os espaçamentos dispostos nas parcelas e as doses de N nas subparcelas. Na colheita das cabeças, retiraram-se amostras das folhas as quais, após secas a 65°C, foram submetidas às análises para os teores de N (N-NO 3 -e N-total), P, K, Ca, Mg e S. Incremento das doses de N proporcionou aumento da produção de MS, dos teores de N (N-NO 3 -e N-total), P e Mg e das quantidades de macronutrientes exportadas pela cultura. Aumento no espaçamento proporcionou maiores teores de N (N-NO 3 -e N-total), P, S e Ca, e menor produção de massa seca e da quantidade de K exportada pela colheita. Termos para indexação:Brassica oleraceae var. capitata, qualidade, nitrato, população. ABSTRACTThe effects of three plant spacings (80x30, 60x30, and 40x30 cm) and five nitrogen rates (0, 75, 150, 225, and 300 kg ha -1 ) were evaluated on biomass yield, macronutrient uptake and tissue concentration of cabbage. A field experiment was carried out at the Universidade Federal de Viçosa from 09/23 to 12/20/2002. The experiment was set in a split-plot design with four replications. Spacings were assigned to the main plots and the N rates were set in the split-plot, arranged in a completely randomized design. At the harvest time, leaves were detached, oven dried and analyzed for N

Effect of Concentration and N:k Ratio in Nutrient Solution for Hydroponic Production of Cucumber

“…Nitrogen is important for the growth and development of plants by altering the source-sink relationship and, consequently, the distribution of assimilates between vegetative and reproductive organs (QUEIROGA et al, 2007). Potassium is the macronutrient most extracted by most vegetables, and it plays an important role in photosynthesis, formation and translocation of carbohydrates, and efficient use of water by the plant (AQUINO et al, 2009). In addition, it improves the quality and weight gain of the fruits and, consequently, their market value (FILGUEIRA, 2008).…”

Accumulation of Macronutrients in Cv. 'Astrus' Cabbage as Influenced by Nitrogen Dose and Plant Population

“…However, in spite of its importance, fertilizer management still lacks information (Cecílio Filho et al, 2013). Among nutrients, nitrogen (N) occupies a very important position not only because of its highly probable environmental impact (Westerveld et al, 2004) but also because it is the second most accumulated nutrient in cabbage plants (Aquino et al, 2009) and has considerable impact on plant growth, productivity, and quality of the commercialized product (Westerveld et al, 2003a;Aquino et al, 2005a;Aquino et al, 2005b;Kolota and Chohura, 2015). Cabbage is very responsive to N, with demands of up to 500 kg N ha -1 , according to the data reported by Westerveld et al (2003a).…”

“…Consequently, the application of N should be studied under the conditions of the crop because the N nutritional status, as determined by the amount of N provided to the plants, interferes directly with the rate of absorption of the other nutrients and the dry matter accumulation of the plant (Aquino et al, 2009;Kolota and Chohura, 2015). Therefore, an important tool to know the demand levels and the moments of highest nutrient demand, as influenced by the N doses, is the progress of nutrient accumulation.…”

“…According to Sady et al (2001), Schellenberg et al (2009), and Kolota and Chohura (2015), alterations in plant spacing change the accumulation of dry matter by the plants. Aquino et al (2009) studied the effects of N doses of 0, 75, 150, 225, and 300 kg ha -1 and plant distances of 80 × 30, 60 × 30, and 40 × 30 cm on the content and exportation of macronutrients in a cabbage crop and verified that the highest doses of N caused increments in the P and Mg levels, whereas an increase in spacing resulted in higher levels of P, Ca, and S, although with reduced dry matter accumulation. Kolota and Chohura (2015) observed that the dose of 150 kg N ha -1 was a limiting factor for the increment of crop yield in plots with more than 44,000 plants ha -1 .…”

“…Several studies have been reported that concern N doses for cabbage plants, including Khan et al (2002), Aquino et al (2005aAquino et al ( , 2005b, Ekbladh et al (2007), Haque et al (2006), Machado et al (2006); Aquino et al (2009);Moreira et al (2011). However, none of these investigations analyzed the accumulation of macronutrients by cabbage plants as influenced by the plant population and N doses.…”