African Journal of
Agricultural Research

  • Abbreviation: Afr. J. Agric. Res.
  • Language: English
  • ISSN: 1991-637X
  • DOI: 10.5897/AJAR
  • Start Year: 2006
  • Published Articles: 6545

Full Length Research Paper

Nitrate concentration and nitrate/ammonium ratio on lettuce grown in hydroponics in Southern Amazon

Daiane de Souza Lauton Wenceslau
  • Daiane de Souza Lauton Wenceslau
  • Campus of Alta Floresta, Mato Grosso State University (UNEMAT), Highway, MT 208, KM 147, Jardim Tropical, Alta Floresta, MT, Zip Code 78.580-000, Brazil.
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Daniele Fatima de Oliveira
  • Daniele Fatima de Oliveira
  • Agriculture Department, Federal University of Lavras (UFLA), Mailbox 3037, Lavras, MG, Zip Code 37200-000, Brazil.
  • Google Scholar
Hudson de Oliveira Rabelo
  • Hudson de Oliveira Rabelo
  • Campus of Alta Floresta, Mato Grosso State University (UNEMAT), Highway, MT 208, KM 147, Jardim Tropical, Alta Floresta, MT, Zip Code 78.580-000, Brazil.
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Guilherme Ferreira Ferbonink
  • Guilherme Ferreira Ferbonink
  • Campus of Alta Floresta, Mato Grosso State University (UNEMAT), Highway, MT 208, KM 147, Jardim Tropical, Alta Floresta, MT, Zip Code 78.580-000, Brazil.
  • Google Scholar
Luiz Antonio Augusto Gomes
  • Luiz Antonio Augusto Gomes
  • Agriculture Department, Federal University of Lavras (UFLA), Mailbox 3037, Lavras, MG, Zip Code 37200-000, Brazil.
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Erica Carina Aparecida Leonel
  • Erica Carina Aparecida Leonel
  • Campus of Alta Floresta, Mato Grosso State University (UNEMAT), Highway, MT 208, KM 147, Jardim Tropical, Alta Floresta, MT, Zip Code 78.580-000, Brazil.
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Gustavo Caione
  • Gustavo Caione
  • Campus of Alta Floresta, Mato Grosso State University (UNEMAT), Highway, MT 208, KM 147, Jardim Tropical, Alta Floresta, MT, Zip Code 78.580-000, Brazil.
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  •  Received: 20 July 2020
  •  Accepted: 12 March 2021
  •  Published: 30 June 2021

Abstract

Lettuce has a predisposition to nitrate accumulation and has led many researchers to develop research to reduce this accumulation. The objective of this study was to evaluate the effect of nitrate concentration (NO3-) and nitrate/ammonium ratio (NO3-:NH4+) on growth, production and accumulation of these nitrogen compounds in lettuce grown in a hydroponic system in southern Amazon. There were performed two experiments with Iceberg lettuce type, in a floating-hydroponic system under protected cultivation. In the first experiment, five nitrate concentrations (2.5, 5.0, 7.5, 10.0 and 15.0 mmol L-1) were evaluated. In the second experiment, the best NO3- : NH4+ ratio was evaluated with five proportions 0:100, 25:75, 50:50, 75:25 and 100:0 in the nutrient solution. At 35 days after transplanting, the evaluations were performed. The nutrient solution containing nitrogen (N) as nitrate source in the concentration of 15.0 mmol L-1 contributed to higher lettuce productivity, being the concentration recommended for hydroponic grown system in southern Amazon. It is recommended to use about 23% of the N in nutrient solution in ammonium form, where higher N-ammonium concentrations are not indicated for Icebeg lettuce type because it reduces the productivity of this green leaf vegetable, causing toxicity symptoms.

Key words: Nitrogen, vegetable, nutrient solution, food security.