Frequencies of application and dilution of nutrient solution in hydroponic cultivation of arugula | Frecuencia de aplicación y dilución de la solución nutritiva en cultivo hidropónico de cohetes | FREQUENCIES OF APPLICATION AND DILUTION OF NUTRIENT SOLUTION IN HYDROPONIC CULTIVATION OF ARUGULA

English. Nutrient solution formulation such as irrigation frequency is fundamental for the success of hydroponic cultivation, since the absorption of nutrients from the nutrient solution is a selective and dynamic process, in which the relative proportion between nutrients in the solution stands out. Thus, the present experiment was conducted to evaluate the production and development of arugula in hydroponic cultivation subjected to different dilutions and frequencies of application of the nutrient solution. The experiments were carried out in a randomized blocks design, with four replicates. A split-plot scheme in a 5 x 2 factorial arrangement was used, which consisted of five dilutions based on the electrical conductivity of the nutrient solution (ECsol: 2.00 (control), 1.81, 1.62, 1.40, and 1.30 dS m-1, corresponding to 100, 90, 80, 70, and 65% concentrations, respectively)  and two application frequencies (variable and fixed), totaling 40 experimental plots, in three production cycles. Shoot fresh mass, shoot dry mass, leaf area, leaf area index, number of leaves, plant height, relative chlorophyll index and macronutrients were analyzed. Regarding shoot fresh mass, there was an increase with the concentration of the nutrient solution, reaching a maximum of 15.52 and 8.40 g plant-1, with nutrient solution was of 1.77 dS m-1 (first cycle) and 1.88 dS m-1 (second cycle). Using only 90% of the recommended nutrient solution is the most appropriate from the commercial point of view, as it led to maximum potential in relation to production, using a smaller number of inputs.

Portuguese. FREQUENCIES OF APPLICATION AND DILUTION OF NUTRIENT SOLUTION IN HYDROPONIC CULTIVATION OF ARUGULA     JENYFFER DA SILVA GOMES SANTOS¹; ALEXSANDRO OLIVEIRA DA SILVA²; CLAUDIVAN FEITOSA DE LARCERDA²; RAIMUNDO NONATO TÁVORA COSTA²; GERONIMO FERREIRA DA SILVA³ E FERNANDO FERRARI PUTTI4   ¹Faculdade de Engenharia Agrícola, Universidade Estadual de Campinas, Av. Cândido Rondon, 501, Cidade Universitária, CEP 13083-875, Campinas, SP. E-mail: jnfgomes@gmail.com ²Departamento de Engenharia Agrícola, Universidade Federal do Ceará, Av. Mr. Hull, 2977, Bloco 804, Pici, CEP. 60356-001, Fortaleza, CE. E-mail: alexsandro@ufc.br; cfeitosa@ufc.br; rntcosta@ufc.br. ³Departamento de Engenharia Agrícola, Universidade Federal Rural de Pernambuco; R. Manuel de Medeiros, Dois Irmãos, CEP: 52071-000, Recife, PE. E-mail: geronimo.silva@ufrpe.br 4Faculdade de Ciências e Engenharia, Universidade Estadual Paulista “Júlio de Mesquita Filho”, campus de Tupã, Rua Domingos da Costa Lopes Jardim Itaipu, CEP: 17602496 - Tupã, SP. E-mail: fernando.putti@unesp.br       1 ABSTRACT   Fertilizer formulation, such as irrigation frequency, is fundamental for the success of cultivation, since the absorption of nutrients from the nutrient solution is a selective and dynamic process. Thus, the present experiment was conducted to evaluate the production of arugula in hydroponic cultivation subjected to different dilutions and frequencies of application of the nutrient solution. The experiments were carried out in a randomized block design with four replicates. A split-plot in a 5 x 2 factorial arrangement was used, which consisted of five dilutions based on the electrical conductivity of the nutrient solution (ECsol: 2.00 (control), 1.81, 1.62, 1.40, and 1.30 dS m-1) and two application frequencies (variable and fixed), totaling 40 experimental plots. Yield and growth variables, relative chlorophyll index and macronutrients were analyzed. Regarding shoot fresh mass, there was an increase with the ECsol, reaching a maximum of 15.52 and 8.40 g plant-1, with nutrient solutions of 1.77 dS m-1 (first cycle) and 1.88 dS m-1 (second cycle). Using only 90% of the recommended nutrient solution is the most appropriate from the commercial point of view, as it led to maximum potential in relation to yield, using a smaller number of inputs.   Keywords: electrical conductivity, greenhouse, temperature sensor     SANTOS, J. S. G.; SILVA, A. O.; LACERDA, C. F.; TÁVORA, R. N.; SILVA. G. F.; PUTTI, F. F.  FREQUÊNCIA DE APLICAÇÃO E DILUIÇÃO DA SOLUÇÃO NUTRITIVA EM CULTIVO DE RÚCULA HIDROPÔNICA     2 RESUMO   A formulação de fertilizantes assim como a frequência da irrigação são fundamentais para o êxito do cultivo, visto que a absorção de nutrientes da solução nutritiva é um processo seletivo e dinâmico. Desta maneira, o experimento foi conduzido objetivando-se avaliar a produção e o desenvolvimento da rúcula em cultivo hidropônico, submetida a diferentes diluições e frequências de aplicação da solução nutritiva. O experimento foi conduzido em blocos casualizados com quatro repetições em parcelas subdivididas em um arranjo fatorial 5 x 2, consistindo de cinco diluições baseadas na condutividade elétrica da solução nutritiva (ECsol: 2,00 (controle), 1,81; 1,62; 1,40 e 1,30 dS m-1) e duas frequências de aplicação (variável e fixa), totalizando 40 parcelas experimentais. Foram analisadas variáveis de rendimento e crescimento, índice SPAD e macronutrientes nas folhas. Observou-se um aumento da fitomassa fresca da parte aérea com incremento da ECsol, atingindo um máximo de 15,52 e 8,40 g planta-1, quando a ECsol foi de 1,77 dS m-1 (primeiro ciclo) e 1,88 dS m-1 (segundo ciclo). O uso de apenas 90% da solução nutritiva recomendada se mostra a mais adequada do ponto de vista comercial, obtendo um potencial máximo com relação a produção, utilizando uma menor quantidade de insumos.   Palavras-chave: condutividade elétrica, casa de vegetação, sensor de temperatura