Frequency of recirculation of nutrient solution in hydroponic cultivation of coriander with brackish water

Mairton G. da Silva,Hans R. Gheyi,Francicleiton F. do Carmo,José A. da Silva Filho,Itamar de S. Oliveira,Tales M. Soares

doi:10.1590/1807-1929/agriambi.v20n5p447-454

Abstract

ABSTRACT The present study used a hydroponic system with leveled channels, in order to evaluate coriander cultivation under different intervals of nutrient solution recirculation and the use of freshwater and brackish water. The experiment was carried out in a randomized block design with five replicates, in a 2 x 4 factorial scheme, from February to March 2014. Two levels of electrical conductivity (EC) of water (0.32 and 4.91 dS m-1) and four frequencies of nutrient solution recirculation (at intervals of 0.25, 2, 4 and 8 h) were evaluated. This experimental design was adopted in the evaluations performed at 10, 15 and 25 days after transplantation (DAT). Additionally, at 21 DAT subplots were established for the evaluation of plant position (initial, intermediate and final) along the hydroponic channels. It is viable to use nutrient solution recirculation every 8 h, without production losses. The use of brackish water (EC = 4.91 dS m-1) may be an alternative for the hydroponic cultivation of coriander, despite the reduction in production, but without any damage on the visual aspect of the product. Plants grown at the initial and intermediate positions along the hydroponic channels showed higher production.

Highlights

A few promising results have been achieved for the rational use of brackish water in the Nutrient Film Technique (NFT) hydroponic system (Santos et al, 2010, 2011; Soares et al, 2010, 2015; Alves et al, 2011; Paulus et al, 2012; Bione et al, 2014; Lira et al, 2015), which can open a new perspective for hydroponics as an economic alternative, provided that brackish water is available
It has been discussed the necessity of hydroponic systems less dependent on electric energy, since the NFT, the most usual system in the Brazilian hydroponics, is an active system that requires pumping for nutrient solution recirculation
Plant roots remain submerged in the nutrient solution (Zanella et al, 2008; Santos et al, 2011); they will only suffer with the effects of recirculation if it is so prolonged that the solution level is reduced

Summary

Introduction

A few promising results have been achieved for the rational use of brackish water in the Nutrient Film Technique (NFT) hydroponic system (Santos et al, 2010, 2011; Soares et al, 2010, 2015; Alves et al, 2011; Paulus et al, 2012; Bione et al, 2014; Lira et al, 2015), which can open a new perspective for hydroponics as an economic alternative, provided that brackish water is available. In the evolution of this research line, it has been pondered that crops of regional interest must be investigated and the studies should not be limited only to the currently important crops in hydroponic markets (notably lettuce, rocket, watercress, tomato etc.) In this context, vegetables such as coriander assume strategic position, because they have attractive prices to the farmer, market in the Northeast region, tolerate higher temperatures compared with other vegetables and their hydroponic cultivation has increased. It has been discussed the necessity of hydroponic systems less dependent on electric energy, since the NFT, the most usual system in the Brazilian hydroponics, is an active system that requires pumping for nutrient solution recirculation In this context, systems such as Floating and Deep Film Technique (DFT) are promising for the rural communities of the semiarid region, where interruptions in water supply are frequent. If the concentration of this nutrient decreases in the nutrient solution, roots reduce respiration, which leads to: lower production of cell energy, lower root growth and lower absorption of nutrients by the active transport

Methods

Results

Conclusion