Yield of lettuce grown in aquaponic system using different substrates

Abstract

A B S T R A C TIn the aquaponic system, the characteristics of the materials used as substrate directly affect plant development, because besides acting as a support base, they must present a surface to fix microorganisms, responsible for the conversion of nutrients into forms more easily available to plants. Thus, the objective of this study was to evaluate the effect of four growing substrates on the yield of lettuce grown in aquaponic system. The experimental design was randomized blocks with four treatments, which corresponded to the substrates, and six replicates. Plants were grown using the nutrient film technique (NFT) system. The substrates used in the experiment were: coconut shell fiber with crushed stone #3, expanded vermiculite, zeolite and phenolic foam. The treatment with phenolic foam was considered as the least suitable for lettuce cultivation in aquaponic system, because it caused lower yield (20.8 t ha -1 ). The treatment using coconut shell fiber with crushed stone #3 was considered as the most adequate, since it led to higher yield (39.9 t ha -1 ) compared with the other substrates analyzed.Produtividade da alface cultivada em sistema aquapônico sob diferentes substratos R E S U M O No sistema de aquaponia as características dos materiais utilizados como substrato afetam diretamente no desenvolvimento das plantas, pois além de atuarem como base de sustentação, devem apresentar uma superfície para fixação de microrganismos, responsáveis pela conversão de nutrientes para formas mais facilmente disponíveis para plantas. Assim, o objetivo desta pesquisa foi avaliar o efeito de quatro substratos de cultivo sobre a produtividade da alface cultivada em sistema de aquaponia. O delineamento experimental utilizado foi em blocos ao acaso, com quatro tratamentos que corresponderam aos substratos e seis repetições. O cultivo das plantas foi realizado utilizando o sistema do tipo NFT (Nutrient Film Technique). Os substratos utilizados no experimento foram: fibra de casca de coco com brita número 3, vermiculita expandida, zeólita e espuma fenólica. O tratamento em que se utilizou espuma fenólica foi considerado o menos adequado para o cultivo da alface em sistema aquapônico, pois apresentou menor produtividade (20,8 t ha -1 ). O tratamento em que se utilizou fibra de casca de coco com brita número 3 foi considerado o mais adequado, uma vez que proporcionou maior produtividade (39,9 t ha -1 ) em relação aos demais substratos analisados.

Yield of lettuce grown in hydroponic and aquaponic systems using different substrates

“…Regarding the yield in the aquaponic system, similar results were observed by Jordan et al (2018). These authors compared the yield of lettuce cultivated in aquaponic system, using coconut shell fiber with crushed stone nº 3 and phenolic foam as substrates, and observed that, despite the higher values of yield, the coconut shell fiber with crushed stone nº 3 led to higher yield (3.99 kg m -2 ) in comparison to the phenolic foam (2.08 kg m -2 ).…”

“…The liquid fraction (wastewater) was separated and stored for subsequent mixture with the biofertilizer. The nutrient solution used for plant cultivation was composed of a mixture of wastewater and biofertilizer at a volumetric proportion of 100:6, as performed in studies on aquaponics under Brazilian conditions (Geisenhoff et al, 2016;Jordan et al, 2018).…”

“…Thus, the utilization of inadequate substrates may lead to reduction in the productive parameters of the crops, as observed for lettuce and tomato (Salam et al, 2014;Geisenhoff et al, 2016). In the cultivation in aquaponic system, substrates must have a fixing surface for microorganisms, responsible for converting nutrients to forms readily available to plants (Jordan et al, 2018).…”

“…In Brazil, the commercial units are virtually inexistent. However, studies have been carried out aiming to adapt the system to the national conditions (Hundley et al, 2013;Geisenhoff et al, 2016;Jordan et al, 2018).…”

Aquaponia: Sistema Que Integra Produ��o De Peixes Com Produ��o De Vegetais De Forma Sustent�vel

“…A literatura brasileira ainda é escassa no que se refere à aquaponia, com apenas algumas publicações recentes (Alves et al, 2015;Jordan, Geisenhoff, Oliveira, Santos & Martins, 2018;De Medeiros, Kautzmann & Taffarel, 2017). O interesse pelo tema tem aumentado nos últimos anos.…”