Yield and leaf concentrations of nutrients of melon crop and fertility of soil fertigated with N and K

Abstract

The use of fertigation as a means of supplying the nutritional needs of crops is a technique widely used among producers. However, it is necessary to improve this technique due, mainly, to the risks of contamination of natural resources. Thus, the objective was to study the productivity and leaf contents of melon nutrients and soil fertility, which presents a high concentration of potassium, when fertigated with doses of nitrogen and potassium in the irrigation water. Five treatments were arranged in randomized blocks with six repetitions. Treatments consisted of combinations of concentrations, in mg L-1, of nitrogen (N) and potassium (K) applied in irrigation water (0-0), (50-0), (50-54), (0-54) and (100-108). The leaf concentrations of nutrients of melon were evaluated at 35 days after planting, and fruit yield and soil fertility at harvest time. The melon cultivated in soil with a high level of K and basal application of 18 kg ha-1 of N in the foundation did not increase production, when fertirrigated with nitrogen and potassium. Although the contents of K, Fe and B varied between the doses of N and K applied, the plants did not have nutritional deficiency. Fertilizer applications in increasing doses contribute to the accumulation of salts in the soil, increasing the risk of salinization.

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

“…According to Dias et al (2010), salinity reduces the availability of water and nutrients to plants, resulting in losses in average fruit weight as the salt concentration increases. In a soil cultivation experiment, Oliveira et al (2020) did not observe a significant response from fruit quality traits. Nascimento et al (2020) described similar findings working with melon in hydroponics, where the K concentrations also did not affect the fruit size-related variables.…”

“…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). S 1 -standard nutrient solution, 2.5 dS m -1 ; S 2 -nutrient solution salinized with NaCl, 5.0 dS m -1 ; S 3 -nutrient solution salinized with NaCl + 50% K, 6.5 dS m -1 ; S 4 -nutrient solution salinized with NaCl + 100% K, 7.5 dS m -1 .…”

“…In this regard, Gurgel et al (2010) also found no effect of K on TA, regardless of irrigation water salinity. Oliveira et al (2020) worked with melon cultivated in soil and found an increase in TA in fruits harvested from plants fertigated with higher K rates, but the authors did not use saline water for irrigation, which may have induced a greater effect of K on the plants.…”

“…In the literature, studies investigating potassium fertilization in melon have described different results regarding qualitative traits (e.g. fruit size and weight) in response to an increase in the K rate in the soil or in hydroponic cultivation (Oliveira, Silva, Medeiros, & Vieira, 2020;Nascimento, Nascimento, & Cecílio, 2020;Gratieri, Cecílio, Barbosa, & Pavani, 2013). Studies can be found on the application of K as a salt stress-mitigating agent in crops such as peanut (Chakraborty, Bhaduri, Meena, & Kalariya, 2016), eggplant (Santos et al, 2018) and bell pepper (R. C. P. Silva et al, 2020a).…”