Effects of amount, electric conductivity, and frequency of a nutrient solution on melon yield and flavor quality

This study aimed to obtain an irrigation strategy for high-quality melon production in a high electric conductivity (EC) value of irrigation areas. The experiment was conducted in Yan'an Shaanxi Province, China, from August 2020 to October 2020. The effects of different irrigation amounts (W), E (EC of a nutrient solution), and frequencies (F) of a nutrient solution on the yield and flavor quality of the oriental melon cultivar ‘Qingnong Cuibao’ cultivated in plastic bags were investigated. Random forest was used to analyze the aromatic substances of melon in the whole growth period and principal component analysis (PCA) was used to obtain the best treatment for melon yield and aromatic substances. Results showed that the main aromatic substances were ethyl acetate, ethyl butyrate, hexanal, octanal, and 2-nonenal during the growth period of melon. The melon fruit ripening stage was the main period of the accumulation of aromatic substances. The W, E and their interaction had substantial effects on the content of esters and yield ( P  < 0.05). The W had greater an effect on aromatic substances and yield than E and F. PCA showed that the optimal water and fertilizer strategy was to irrigate 1.68 L/plant nutrient solution with 3.53 mS/cm EC for 7 times one day. The results of this experiment could provide a reference for melon production in irrigation areas with a high E value.