Nutrient solution salinity effect of greenhouse melon (Cucumis melon L. cv. Néctar)

Abstract

In Mossoró-RN, which is part of the semi-arid region of Brazil, a large part of the country’s melon production is concentrated, whose great potential is currently limited by water quality due to salt concentration. Therefore, the objective of this work was to investigate the use of saline nutritive solutions in the irrigation of greenhouse melon (Cucumis melo L. cv. Néctar) culture in coconut fiber. The experiment was carried out using a randomized block design with a 5 x 2 factorial arrangement, with four replications, where the treatments consisted of nutritivesolutions with five salinity levels (1.25 - control, 1.43, 1.86; 2.96 and 4.86 dS m-1) and for two different times to evaluate fruit quality parameters (at harvest and after 12 days of storage). Increasing the salinity in the nutrient solution reduces fruits’ mean weight, while total yield is only reduced with EC above 3.5 dS m-1. Fruit length anddiameter and peel and pulp thickness, SS and pH, decrease when submitted to nutrient solution with EC above 3.8 dS m-1. The peel and pulp thickness, pulp internal cavity, firmness, SS, pH, TA and fruit SS/TA ratio were influenced by the storage period.

Potassium nutrition as a strategy to mitigate salt stress in melon grown under protected cultivation

“…The lack of a salinity effect on the firmness of the melon pulp observed in the present study is in agreement with results presented by other authors (Pereira et al, 2017;Dias et al, 2018). This is an essentially important attribute when it comes to postharvest handling, as firmer fruits better resist mechanical injuries during transport and marketing operations.…”

“…In the present study, IC showed the same response as that described by Dias et al (2018), who reported a reduction in this variable at salinity levels greater than 3.0 dS m -1 . Queiroz (2016) worked with 'Gália' melon grown in fiber substrate and fertigated under K concentrations and found an increase in IC in response to the increasing K rates; however, no salinized nutrient solution was used.…”

“…The nutrient solutions influenced the titratable acidity (TA) of the fruits, whose highest values occurred with the addition of NaCl combined with the extra addition of 50% K (S 3 ). This result did not differ from those achieved with the other salinized Increases in TA in melon fruits in response to salinity have also been reported in soil (Gurgel, Oliveira, Gheyi, Fernandes, & Uyeda, 2010) and hydroponic (Dias et al, 2018) cultivation. In this regard, Gurgel et al (2010) also found no effect of K on TA, regardless of irrigation water salinity.…”

“…In an experiment investigating the quality of fruits produced in a greenhouse under salinity levels, Dias et al (2018) observed a tendency towards a decrease in pH at the salinity level of 4.9 dS m -1 . Oliveira (2020) worked with melon at different concentrations of N and K applied via fertigation and also detected a tendency towards a pH decline in Mean values followed by the uppercase same letter in the rows and lowercase letters in the columns do not differ from each other by Tukey's test (p ≤ 0.05).…”

“…Commercial growing of melon is traditionally held in field conditions. However, studies have recently been developed with cultivation in protected environments using substrate, especially regarding the use of saline water (Dias et al, 2010(Dias et al, , 2018Morais, Aroucha, Oliveira, Medeiros, & Nascimento, 2019). The melon crop has moderate tolerance to salinity, with its yield dropping at salinity levels greater than 2.2 dS m-1 in the soil saturation extract.…”