Produção de cebola cultivada sob diferentes densidades de plantio

Abstract

Propôs-se, neste trabalho, avaliar o desempenho agronômico da cebola em diferentes densidades de plantio, em Mossoró, RN. O delineamento experimental utilizado foi em blocos casualizados completos em esquema fatorial 2 x 5, com quatro repetições. Os tratamentos consistiram da combinação de duas cultivares de cebola (Vale Ouro IPA 11 e Bella Dura) e cinco densidades de plantio (80, 120, 160, 200 e 240 plantas m-2). As características avaliadas foram: classificação dos bulbos em função do diâmetro transversal; produtividade total, comercial e não comercial; massa média dos bulbos; massa seca dos bulbos e relação do formato de bulbos. A cultivar mais produtiva foi a IPA 11, com produtividade total de 26,76 t ha-1. A densidade que proporcionou maior produtividade total (30,48 t ha-1) foi a de 204 plantas m-2 e comercial (24,74 t ha-1) foi a de 161 plantas m-2. O incremento da densidade reduziu a massa média e seca de bulbo, percentagem de bulbos das classes 2 e 3, mas aumentou a produtividade não comercial, percentagem de bulbos classe 1 (refugo) e relação de formato de bulbo. A cultivar Vale Ouro IPA 11 foi superior ao híbrido Bella Dura com relação à produtividade total de bulbos, massa média de bulbos comerciais e relação de formato, independentemente da densidade de plantio.

Performance of onion cultivars as a function of spacing between plants

“…Menezes Júnior & Vieira Neto (2012) observed a reduction of 97.4% in the yield of bulbs class 2 with the reduction in density from 600 to 200.000 plants ha -1 . Henriques et al (2014) also observed a reduction of 23.4% as the spacing increased from 3 to 10 cm between plants, confirming the results found in the present study.…”

“…All of these factors promoted better conditions for plant development, contributing to yield higher than the mean of the country (27.84 t ha -1 ) and Northeast region (32.72 t ha -1 ) (IBGE, 2017). Total and marketable yields were higher than those reported by Henriques et al (2014), who studied two onion cultivars (IPA 11 and Bela Dura) at different spacings between plants under the conditions of Mossoró, RN, and found maximum values for total and marketable yields of 30.48 and 24.74 t ha -1 at the spacings of 3 and 5 cm, respectively. Nevertheless, Baier et al (2009) worked with three planting densities (50, 75 and 100 plants m²) in the onion crop and obtained maximum yield of 92.2 t ha -1 at the highest density studied (100 plants m -2 ).…”

“…Reduction in unmarketable yield is a desirable characteristic for the onion producer, since this type of bulb has low commercial value. Reduction of unmarketable bulbs with the increase in spacing was also found by Henriques et al (2014).…”

“…The cultivars Rio das Antas and Serena exhibited the highest percentages of bulbs class 4 ( Table 2). The good tolerance, high vigor and hybrid genetic pattern possibly contributed to these results according to Henriques et al (2014). The cultivar Rio das Antas, at spacings of 8 and 10 cm, was superior to the others regarding the percentage of bulbs class 4, not differing from Serena at the spacing of 6 cm (Table 2).…”

Onion yield as a function of soil tillage system and soil water content

“…This finding is consistent with the results obtained by Henriques et al (2014), evaluating the production of two onion cultivars at different planting densities. These authors observed that the increase in planting density caused an increasing linear effect on the non-marketable yield and a quadratic effect on the total and marketable yields.…”