Optimization of root spraying time for fresh onion (Allium cepa L.) cultivation in aeroponics

Abstract

Green leafy vegetables are successfully grown in the aeroponic systems. The faster harvest cycles, predictable results, higher productive yield, better crop color, texture, nutrition and flavor are the advantages of the aeroponically growing. We have studied optimization of nutrient spray time on roots of fresh onion. Plants were grown in glasshouse during winter and we have built an own aeroponic system. The spray interval of 10 min was constant and five different spray/misting times 7, 10, 15, 18 and 21 s were studied. The highest biomass yield including root and the highest edible fresh onion yield were obtained from 18 s spray time with 10 min spray internal. In fact, relationships between spray times and edible fresh onion yield showed that the optimal spray time was 17 s. Remarkable effects of spray times were observed in EC of the onion and the highest was observed from 18 s. Total phenol content was gradually decreased with the increased spray times. The 18 s provided the highest flavonoid and the succinic acid productions in fresh onion. Ascorbic acid content was not affected by the spray time. There was no meaningful relationship between the mineral content of onion and spray time. Regular increases in mineral elements in onion were not observed with increasing spraying time.