African Journal of
Agricultural Research

  • Abbreviation: Afr. J. Agric. Res.
  • Language: English
  • ISSN: 1991-637X
  • DOI: 10.5897/AJAR
  • Start Year: 2006
  • Published Articles: 6688

Full Length Research Paper

Nitrogen and potassium concentration in the nutrients solution for the production of tomato (Solanum lycopersicum)

Francisco Reinaldo Rodrigues Leal
  • Francisco Reinaldo Rodrigues Leal
  • Universidade Estadual de Piaui - UESPI, Av. Senador Helvídeo Nunes de Barros s/n, bairro Junco, 64600-00, Picos, Piaui, Brasil.
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Arthur Bernardes Cecilio Filho
  • Arthur Bernardes Cecilio Filho
  • Universidade Estadual Paulista - UNESP, Via de acesso Prof. Paulo Donato Castellane, s/n, 14884-900, Jaboticabal, São Paulo, Brasil.
  • Google Scholar
Juan Waldir Mendoza-Cortez
  • Juan Waldir Mendoza-Cortez
  • Universidade Estadual Paulista - UNESP, Via de acesso Prof. Paulo Donato Castellane, s/n, 14884-900, Jaboticabal, São Paulo, Brasil.
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Jose Carlos Barbosa
  • Jose Carlos Barbosa
  • Universidade Estadual Paulista - UNESP, Via de acesso Prof. Paulo Donato Castellane, s/n, 14884-900, Jaboticabal, São Paulo, Brasil.
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  •  Received: 10 December 2014
  •  Accepted: 07 April 2015
  •  Published: 09 April 2015

Abstract

This study viewed to determine the effects of N and K concentrations in the nutrients solution on the productivity and fruit quality of tomato plants growing in a hydroponic medium. The experiment was carried out from January through April of 2011, in Jaboticabal, São Paulo, Brazil. The experiment was divided in two phases – the first took place during the vegetative development of the plants and it consisted of the doses of N of 137.5, 192.5, 247.5, and 302.5 mg L-1, keeping K concentration at 275 mg L-1. In the second phase, during plant reproductive growth, the treatments consisted of the K doses of 137.5, 206.25, and 275 mg L-1 and the N dose which yielded the best results during the previous phase. At the end of the vegetative phase, leaf N content, first raceme height, internode length, and stem diameter were determined, and it was verified to have no significant effect of treatments upon the characteristics, and therefore considered the lowest N rate (135.5 mg L-1) as most appropriate. At the reproductive phase, increasing doses of N caused yield reductions of clusters 1 and 2. As to K concentrations, the largest yield of cluster 2 resulted from the concentration of 202.5 mg L-1. The largest fruit yield resulted from the N and K concentrations of 177.2 and 188.7 mg L-1 respectively, this means N:K relation of 1:1.1. The soluble solids content of fruits from clusters 1 and 2 was not influenced by variations in N and K concentrations.

 

Key words: Greenhouse, hydroponic system, nitrogen:potassium ratio, productivity.