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Abstract
Papaya (Canca papaya L.) is one of the leading fruit trees in Brazil, mainly in the Northeast region. However, some regions suffer from water scarcity, making wastewater reuse a viable alternative for crop production. Also, biostimulants may be used to maximize papaya growth and development. Thus, this work aimed to evaluate the use of Acadian® biostimulant in the growth of Formosa papaya seedlings irrigated with different concentrations of fish-farming wastewater. The experiment was block randomized in a 2 x 5 factorial scheme, use and non-use of biostimulant and five concentrations of wastewater (0, 10, 20, 30, and 40%) diluted in potable water, with four replicates. Qualitative data were compared by t-test at 5% probability, and quantitative data were submitted to regression analysis. Results showed that high concentrations of wastewater negatively affect the production of Formosa papaya seedlings. Acadian® negatively influences plant height, number of leaves, and the ratio between shoot and root. However, the seaweed biostimulant positively influenced the chlorophyll content index.
Keywords: Ascophyllum nodosum, Carica papaya L., initial growth, water reuse
Introduction
Papaya (Carica papaya L.) is an herbaceous plant from South America that has been adapted to tropical and subtropical climates and get worldwide economic importance (Figueiredo et al., 2018). In Brazil, the Northeast region is the leading producer, mainly in Bahia, Espirito Santo, and Rio Grande do Norte States (Anuario Brasileiro de Fruticultura, 2018).
Some environmental factors, such as water scarcity may be a limiting factor for the growth and development of papaya, like in the Brazilian semiarid region, where the climate is characterized by low rainfall and relative humidity, and high temperatures. In this sense, the use of wastewater diluted with supply water for irrigation can become advantageous due to water scarcity and the dispute over the priority use of drinking water (Oliveira et al., 2017).
Wastewater from different sources has been used successfully for irrigation of many crops such as Eucalyptus urophylla L. (Batista et al., 2014), Helianthus annuus L. (Oliveira et al., 201 7) and Raphanus sativus L. (Dantas et al., 2014). Also, biostimulants, mainly those based on seaweed extracts, has been used as an economically and ecologically alternative to fertilizers (Jayaraman et al., 2011).
Acadian® is a biostimulant based on Ascophyllum nodosum L. seaweed extract that...