Journal of Agricultural Studies ISSN 2166-0379 2020, Vol. 8, No. 2 http://jas.macrothink.org 466 Evaluation of the Non-destructive Method Efficiency of Estimating Nitrogen Content in Jambu Plants Grown in Hydroponic System Italo Marlone Gomes Sampaio (Correspondins author) Soil Science department, Institute of Agrarian Sciences, Federal Rural University of Amazon, CEP. 066.077-830. Belém, Pará, Brasil. E-mail: italofito@gmail.com Mário Lopes da Silva Júnior Soil Science department, Institute of Agrarian Sciences, Federal Rural University of Amazon, CEP. 066.077-830. Belém, Pará, Brasil. E-mail: mario.silva_junior@yahoo.com.br Erika da Silva Chagas Soil Science department, Institute of Agrarian Sciences, Federal Rural University of Amazon, CEP. 066.077-830. Belém, Pará, Brasil. E-mail: erikachagas8@gmail.com Ricardo Falesi Palha de Moraes Bittencourt Soil Science department, Institute of Agrarian Sciences, Federal Rural University of Amazon, CEP. 066.077-830. Belém, Pará, Brasil. E-mail: ricardofalesibitten@gmail.com Vivian Christine Nascimento Costa Soil Science department, Institute of Agrarian Sciences, Federal Rural University of Amazon, CEP. 066.077-830. Belém, Pará, Brasil. E-mail: vivian.costa.1993@gmail.com Dandara Lima de Souza Soil Science department, Institute of Agrarian Sciences, Federal Rural University of Amazon, CEP. 066.077-830. Belém, Pará, Brasil. E-mail: dandaralima23@gmail.com Washington Aleksander Savaris dos Santos State University of Pará, CEP – 666.404-54. Belém, Pará, Brasil.