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Abstract(s)
O cultivo de morango por hidroponia é uma técnica de crescente interesse tanto a nível agronómico como alimentar. Atendendo ao elevado custo que este tipo de cultivo aporta é premente levar a cabo estudos que permitam validar os seus efeitos ao nível de produtividade, firmeza e carga microbiológica dos frutos afim de se otimizar a sua potencialização. Este estudo teve como objetivo não só avaliar a potencialidade do método de cultivo de hidroponia comparativamente com o solo, como também avaliar o efeito da aplicação de um bioestimulante comercial à base de extratos de algas e da aplicação de Ca(NO3)2 na produtividade e na qualidade do morango produzido em sistema hidropónico. Nesse sentido, foram testadas três frequências de aplicação (a cada 7, 15 e a cada 30 dias, durante todo o ciclo cultural), três doses de bioestimulante (1,5; 3,0 e 4,5 L/ha) e duas doses de Ca(NO3)2 (5,0 e 10,0 kg/ha). Generalizando, os resultados demostram que a aplicação do bioestimulante ao longo de todo o ciclo cultural é mais eficaz na obtenção de uma maior produtividade comparativamente à aplicação apenas após o início da floração. As aplicações com 1,5 L/ha além de induzirem uma colheita mais precoce ainda são mais eficazes quando aplicadas com uma maior frequência e doses de 4,5 L/ha são mais satisfatórias quando aplicadas com menor frequência. A aplicação de bioestimulante e de Ca(NO3)2 influenciou a concentração de minerais nos frutos e levou a um aumento do conteúdo em compostos fenólicos, antocianinas, vitamina C e atividade antioxidante dos mesmos. Foi observado ainda um comportamento diferenciado entre as cultivares testadas relativamente à firmeza e à carga microbiológica do morango tendo sido obtidos resultados satisfatórios para os morangos que cresceram em sistema de hidroponia relativamente aos de solo, para ambos os parâmetros avaliados. Foram realizados testes que permitiram aferir que a firmeza dos frutos é altamente dependente do seu grau de maturação e do calibre. Estudou-se ainda o efeito de desinfetantes na carga microbiológica, tendo-se obtido resultados satisfatórios para o ácido acético 2%. Os resultados globais deste estudo evidenciam claramente que a escolha do tipo de cultivo, das doses de aplicação de bioestimulante e de Ca(NO3)2 tem um impacto a nível produtivo e a nível físico-químico dos frutos.
The strawberry cultivation by hydroponic is a technique of growing interest in both food and plant science. However, due to high costs, such cultivation technique requires further evaluations concerning its effects on productivity, firmness and microbiological load of fruit in order to support further decimintionation of the technique. The aim of this study was to evaluate the potential of hydroponic cultivation methods compared with the traditional methods, as well as assess the effect of a commercial bio-stimulant (based in algae extracts) and (Ca(NO3)2) on productivity and quality of strawberries produced in hydroponic system. Whereas, three application frequencies were tested, in the rooth (every 7, 15 and every 30 days during the whole culture cycle) and three doses of bio-stimulant (1,5, 3,0 and 4,5 L/ha), and two doses of Ca(NO3)2 (5,0 and 10,0 kg/ha). Generally, the results demonstrate that application of the bio-stimulant throughout the crop cycle is more effective in obtaining a higher productivity compared to the application only after the onset of flowering. Applications with 1,5 L/ha induced an early harvesting and were more effective when applied at a higher frequency. However, administrations with a concentration of 4,5 L/ha are more effective when applied less frequently. Application of bio-stimulant and Ca(NO3)2 influenced the mineral concentration in the fruit and led to an increase in antioxidant activity of the fruit due to increased contents of phenolic compounds, anthocyanins , and Vitamin C. It was also observed different behaviour among the cultivars tested for firmness and microbiological parameters. It was found that strawberries grown in hydrponic circunstances presented higher microbilogical stability when compared with strawberries produced in soil. The degree of maturity and caliber of the strawberries was also found to influence the firmeness of the fruit. Notwhitstanding, it was also shown that acetic acid at 2% effectively reduced microbial load on strawberries produced under both conditions. The results of this study clearly show that the choice of the type of crop, doses of bio-stimulant and Ca(NO3)2 has an impact on production levels and physical-chemical characteristcs of the fruits.
The strawberry cultivation by hydroponic is a technique of growing interest in both food and plant science. However, due to high costs, such cultivation technique requires further evaluations concerning its effects on productivity, firmness and microbiological load of fruit in order to support further decimintionation of the technique. The aim of this study was to evaluate the potential of hydroponic cultivation methods compared with the traditional methods, as well as assess the effect of a commercial bio-stimulant (based in algae extracts) and (Ca(NO3)2) on productivity and quality of strawberries produced in hydroponic system. Whereas, three application frequencies were tested, in the rooth (every 7, 15 and every 30 days during the whole culture cycle) and three doses of bio-stimulant (1,5, 3,0 and 4,5 L/ha), and two doses of Ca(NO3)2 (5,0 and 10,0 kg/ha). Generally, the results demonstrate that application of the bio-stimulant throughout the crop cycle is more effective in obtaining a higher productivity compared to the application only after the onset of flowering. Applications with 1,5 L/ha induced an early harvesting and were more effective when applied at a higher frequency. However, administrations with a concentration of 4,5 L/ha are more effective when applied less frequently. Application of bio-stimulant and Ca(NO3)2 influenced the mineral concentration in the fruit and led to an increase in antioxidant activity of the fruit due to increased contents of phenolic compounds, anthocyanins , and Vitamin C. It was also observed different behaviour among the cultivars tested for firmness and microbiological parameters. It was found that strawberries grown in hydrponic circunstances presented higher microbilogical stability when compared with strawberries produced in soil. The degree of maturity and caliber of the strawberries was also found to influence the firmeness of the fruit. Notwhitstanding, it was also shown that acetic acid at 2% effectively reduced microbial load on strawberries produced under both conditions. The results of this study clearly show that the choice of the type of crop, doses of bio-stimulant and Ca(NO3)2 has an impact on production levels and physical-chemical characteristcs of the fruits.
Description
Keywords
Hidroponia Bioestimulante Ca(NO3)2 Firmeza Microbiologia Desinfeção Produtividade Minerais Vitamina C Antocianinas Fenólicos Brix pH Cor Hydroponics Bio-stimulant Firmness Microbiology Disinfection Productivity Minerals Vitamin C Anthocyanins Phenolic Colour