Big data analysis on flue-curing process of tobacco leaves in Henan based on data acquisition via internet of things (IoTs)

In order to optimize tobacco flue-curing processing parameters, the temperature and humidity data during flue-curing were collected from 3 tobacco planting areas in Henan by using the technology of IoTs (internet of things). The durations and indexes of temperature and humidity of the curing process were analyzed and compared with flue-curing technologies at home and abroad. The results showed that: 1) The total curing time of middle and upper tobacco leaves was mainly in ranges of 6.5-8.0 days and 7.0-8.5 days respectively, and the fluctuation of wet bulb temperature was relatively drastic during the flue-curing process of upper leaves. 2) The proportions of yellowing, color-fixing and stem-drying durations to total flue-curing time were about 40%, 35% and 25% respectively in south and west Henan, while the yellowing duration in middle Henan was longer, accounting for 55% of the total flue-curing time. 3) The temperatures during yellowing, color-fixing and stem-drying stages were mainly in ranges of 40-42 ℃, 43-48 ℃ and above 61 ℃ respectively. The wet bulb temperature from the late yellowing stage to stem-drying stage of each area was 1-2 ℃ lower than the three-phase curing technology. 4) Correlation analysis indicated that the regulation of wet bulb temperature from yellowing stage to middle color-fixing stage was closely related with the curing process. Considering the flue-curing technology at home and abroad, the durations of yellowing stage at 38 ℃ and color fixing stage at 54 ℃ could be appropriately prolonged, and the wet bulb temperature from late yellowing stage to color-fixing stage should be reasonably regulated to avoid drastic fluctuation, so as to promote the rational transformation of chemical components in tobacco leaves during flue-curing process.