Doses De Nitrogênio No Desenvolvimento De Mudas Altas De Maracujá-Amarelo

Abstract

RESUMOCom a disseminação do vírus do endurecimento dos frutos do maracujazeiro amarelo, surge a necessidade de produção de mudas maiores e mais vigorosas. Atualmente, há carência de informações sobre os aspectos nutricionais na formação de mudas com qualidade; desta forma, objetivou-se avaliar doses de nitrogênio (N) no desenvolvimento de mudas altas de maracujá amarelo. O delineamento experimental foi em blocos casualizados, com cinco tratamentos e cinco repetições. Os tratamentos foram compostos por doses de nitrogênio (0, 0,17, 0,34, 0,51 e 0,68 g L -1 ) na forma de nitrato de cálcio, aplicadas em forma de solução nutritiva. As doses 0,34, 0,51 e 0,68 g L -1 N aumentaram o teor de N nas folhas, proporcionando maior desenvolvimento em altura, diâmetro do caule e área foliar. A dose de 0,34 g L -1 N pode ser indicada na produção de mudas altas, visto que alcançou altura, diâmetro, índice de cor verde e formação de área foliar muito próximos à máxima dose de 0,68 g L -1 N e médias superiores à dose de 0,51 g L -1 N, contudo, estudos em campo são necessários para validação. As concentrações (g kg -1 ) nas folhas com a dose de 0,34 g L -1 N foram: N (21), P (0,86), Mg (2,58) e B (29,6). Estes valores estão adequados para mudas altas, confirmados pelos índices observados.Palavras-chave: Passiflora edulis; nutrição mineral; índice de cor verde. ABSTRACTDue to Cowpea aphid-borne mosaic virus dissemination, therefore it is necessary to produce larger and more vigorous seedlings and, currently, there is a lack of information about the nutritional aspects in the formation of these seedlings with quality. This study aimed to evaluate the nitrogen doses (N) applied on side-dressing on development of tall seedlings of yellow passion-fruit. The experimental design was a randomized block, with five treatments and five replications. The treatments consisted of five N levels (0; 0.17; 0.34; 0.51 and 0.68 g L -1 ) as calcium nitrate, applied on side-dressing in the form of nutrient solution, weekly until 90 days after emergence. Nitrogen rates from 0.34, 0.51 and 0.68 g L -1 increased the N content in the leaves, providing further development in height, stem diameter and leaf area. The rate of 0.34 g L -1 of N may be indicated in the tall seedlings production, because reached height, diameter, green index, and leaf area formation very close to the maximum rate of 0.68 g L -1 N and average higher the rate of 0.51 g L -1 N, however, field studies are needed to validate. The concentrations (g kg -1 ) in leaves at a rate of 0.34 g L -1 of N were: N (21), P (0.86), Mg (2.58), B (29.6), these values are suitable for tall seedlings confirmed by the observed rates.

Nitrogen fertilization and spacing in productivity and quality of passion fruit implanted with advanced seedlings

“…present in the soil 12.1 g dm -³, different from the present experiment that studied N dose in soil with higher O.M., 31.0 g dm -³. Bertani et al (2019) also observed the effect of the N dose increase in the PSD as well as in the PSL in advanced passion fruit seedlings. N influence on the PSD was verified in the evaluations at 60, 75, 90 days after the emergency (DAE), while at 45 DAE was not significant.…”

“…However, although nitrogen (N) is the most extracted nutrient and the second most exported (HAAG et al, 1973;MATTAR et al, 2018) the recommended N amount for the crop varies between 94 and 235 kg ha -1 year -1 (RIPADO, 2010;MIYAKE et al, 2018). In addition, studies showed variable responses on N effect on fruit quality as well as nutritional studies in area with the presence of HFV, the performance evaluation of advanced seedlings in the field on N doses effect and its correlation with productivity are scarce (AULAR et al, 2014;MIYAKE et al, 2018;BERTANI et al, 2019). This lack of information hinders the elaboration of a precise recommendation to the rural producer, which can harm the activity productivity recovery.…”

Alternative Substrates for Production of Yellow Passion Fruit Seedlings

“…The use of tall seedlings, for example, improves the quality of passion fruit when compared to conventional seedling planting (Santos et al, 2017a). Besides, this management technique also helps in controlling the fruit-hardening virus (Bertani et al, 2019). The highest plant height values found in the present study were 20.18 and 17.30 cm for seedlings produced with about 60% cattle manure or Organomais, respectively, added to the commercial substrate.…”

Quality Index of Passion Fruit Seedlings by Using Physically Parameters

“…Santos et al (2011) evaluating different sources of N (ammonium sulfate, ammonium nitrate and urea) in the initial growth of yellow passion fruit plants, observed that the plants obtained very close values with SPAD index of 56.36, 57.17 and 59.02 for chlorophyll content. Bertani et al (2019) evaluating the feasibility of using the SPAD index as indicative of the nutritional status of plants in relation to nitrogen, observed to be a good index, since they presented approximate values of nitrogen content.…”