Crescimento e absorção de macronutrientes na cultura da melancia no estado de Pernambuco

Abstract

Objetivou-se avaliar o crescimento e acúmulo de macronutrientes por cultivares de melancia no estado de Pernambuco. O trabalho foi conduzido na estação experimental Bebedouro (Petrolina-PE) pertencente à EMBRAPA Semiárido, no período de setembro a dezembro de 2009. O solo da área experimental foi classificado como argilosolo vermelho-amarelo eutrófico (EMBRAPA, 1999). O delineamento utilizado foi em blocos casualizados completos, com quatro repetições em esquema fatorial 2x5. Os tratamentos resultaram da combinação de duas cultivares de melancia (Quetzale e Shadow) e cinco épocas de coletas: 15, 25, 35, 45 e 55 dias após o transplantio. Em cada coleta foram utilizadas três plantas por repetição. A unidade experimental para o experimento foi constituída por três fileiras de plantas de 10,5 m de comprimento, com espaçamento de 2,0 x0,50m perfazendo um total de 63,0 m2. As coletas de plantas foram realizadas na fileira central. As cultivares Quetzale e Shadow apresentaram crescimento inicial lento, intensificando a partir dos 25 dias após o transplantio. Maiores incrementos na matéria seca total da parte aérea e do fruto ocorreram no período de 45 a 55 dias após o transplantio. Na colheita, a parte aérea e o fruto da cultivar Quetzale apresentaram os maiores acúmulos de 52%. E os macronutrientes foram absorvidos pelas cultivares na seguinte ordem: K ˃N˃Ca˃P˃Mg.Growth and macronutrient absorption in the watermelon crop in the State of PernambucoAbstract: This study aimed to evaluate the growth and accumulation of macronutrients by watermelon cultivars in the state of Pernambuco. The experiment was conducted in the experimental station of Bebedouro (Petrolina-PE) which belongs to EMBRAPA Semiarid from September to December in 2009. The soil of experimental area was classified as red-yellow eutrophic claylish soil.The experimente was done in a complete randomized with four replications in a factorial scheme 2 x 5. The treatments resulted from the combination os two cultivars of watermelon (Quetzale and Shadow) and five collects: 15, 25, 35, 45 and 55 days after transplanting. Three plants were used per repetition in each collect. The experimental unit consisted of three rows of plants with 10,5 m long, spaced by 2,0 x 0,50 m making up 63,0 m2. The plants were collected from the central row. The cultivars Quetzale and Shadow presented slow initial growth, improving from the twenty-fifth day after transplanting. The largest increases in the total dry matter of the aerial part and fruit happened between 45 and 55 days after transplanting. At harvest, the aerial part and the fruit of the cultivar Quetzale presented the largest accumulations , in a total of 52%. And the macronutrients were absorbed by both cultivars in the following order: K ˃ N ˃ Ca˃P ˃ Mg.

Growth and accumulation of nutrients of ‘Top Gun’ watermelon

“…The continuous accumulation of dry mass in leaves and stems during the reproductive phase characterized the habit of indeterminate growth of the watermelon plant. This result is in accordance with that reported by Vidigal et al (2009), in Crimson Sweet, and Aguiar Neto et al (2016) in Shadow and Quetzale, which observed increases in the accumulation of dry mass in the aerial part of the plant up until the harvest of the fruit.…”

“…Phase V2 started with the emission of the secondary and tertiary stems and ended when flowering began (24 to 35 DAS) (Figure 1). By then, it had accumulated 3.8% of the total dry mass obtained at the end of the cycle, similar to that reported by Vidigal et al (2009) and Aguiar Neto et al (2016) Phase R1 started with flowering and went up until 44 DAS when the first fruit was 8 cm in diameter (Figure 1). During this period, there was a great accumulation of dry mass in the stems and leaves, with increments rates of 5.6 and 9.53 g day -1 , respectively.…”

“…At the end of the cycle, stems, leaves and fruit accumulated 145.0; 241.5 and 856.0 g plant -1 , which corresponded to 11.6%, 19.5% and 68.9% of the total dry mass of the plant, respectively. In Quetzale and Shadow watermelons, the fruit and the aerial part (leaves and stems) were 48% and 51%, respectively (Aguiar Neto et al, 2016). Grangeiro & Cecílio Filho (2004) verified that the 'Tide' watermelon plant presented a proportion of the vegetative part of 31% and for fruit 69% of the accumulated dry mass, values close to those observed in this study.…”

“…At the end of the cycle, the contribution of stems, leaves and fruits was 9.8%; 21.8% and 68.4% of the total nitrogen accumulated in the plant, respectively. In the Quetzale and Shadow watermelons, Aguiar Neto et al (2016), reported that the greatest nitrogen demand occurred during the period from 45 to 55 DAT and that the fruit contributed with 35% and 41% of the total nitrogen accumulated, respectively. Santos et al (2016) in Precious Petite and BGCIA 941 watermelons found the highest demands for nitrogen, 15.0 and 20.9 g plant -1 , were from 20 to 70 DAS and from 32 to 60 DAS, respectively.…”

“…In Brazil, the process of nutrient accumulation in watermelon involving various hybrids was carried out by a number of researchers including: Grangeiro & Cecílio Filho (2004) who worked with the Tide hybrid and Grangeiro & Cecílio Filho (2005a, b) worked with the seedless hybrids, Shadow and Nova; Vidigal et al (2009) worked with the cultivar Crimson Sweet; Lucena et al (2011) worked with the Quetzale hybrid; Aguiar Neto et al (2016) worked with the Quetzale and Shadow hybrids; and Schiavon worked with the Master hybrid. Similarity was found only in the decreasing order of accumulated nutrients of the watermelon, those being K, N, Ca.…”