Production and post-harvest quality of mini-watermelon crop under irrigation management strategies and potassium fertilization¹

Produção e qualidade pós-colheita de mini-melancieira sob estratégias de manejo de irrigação e adubação potássica

HIGHLIGHTS:

Despite the deleterious effect of salinity on the diameter of mini-watermelon fruits, their appea-rance was not negatively affected.

Salt stress in the flowering and maturation stages does not compromise the production of mini-watermelon.

Water salinity of 4.0 dS m^-1 reduces soluble solids and ascorbic acid in fruits when plants are fertilized with 150 mg K₂O kg^-1 of soil.

ABSTRACT

The occurrence of water sources with a high concentration of salts stands out as a limiting factor for production in Northeast Brazil. Thus, the search for strategies that minimize the effect of salt stress on crops is of fundamental importance. In this context, this study was conducted with the objective of evaluating the production and post-harvest quality of Sugar Baby mini-watermelon fruits under different irrigation management strategies with saline water and potassium fertilization. The experiment was conducted in a greenhouse, using a randomized block design, in an 8 × 3 factorial scheme, with three replicates, corresponding to eight saline water irrigation management strategies (No stress throughout the crop cycle; irrigation with saline water in the vegetative, vegetative/flowering, flowering, flowering/fruiting, fruiting, fruiting/maturation and fruit maturation stages) and three doses of potassium (50, 100 and 150% of the recommended dose). The dose of 100% corresponded to 150 mg K₂O kg^-1 of soil. Water with low and with high electrical conductivity (0.8 and 4.0 dS m^-1, respectively) was used. Irrigation with water of 4.0 dS m^-1 in the flowering and fruit maturation stages is a promising strategy for the cultivation of mini-watermelon, as it does not compromise production. Fertilization with 50% of K₂O recommendation can be used in the cultivation of mini-watermelon without losses in yield. Mini-watermelon plants fertilized with 150% of K₂O recommendation and irrigated with water of high salt concentration continuously in the vegetative/flowering and fruiting stages reduced the contents of soluble solids and ascorbic acid in the fruits.

Key words:
Citrullus lanatus L.; salt stress; osmoregulator