PRE-WILTING BURLEY TOBACCO TO ENHANCE MANUAL AND MECHANICAL HARVESTING AND HOUSING

Traditionally, burley tobacco has been harvested by hand because the green plant weight, volume, and leaf fragility make mechanical harvesting very challenging. This study examined possible ways to wilt a plant still standing in the field (termed ‘pre-wilting’) to reduce weight, volume, and leaf fragility. Several methods of pre-wilting burley tobacco plants in the field were explored including: root pruning, stalk girdling, freezing with liquid nitrogen, and burning. Experiments were conducted in three locations over three consecutive years during the tobacco harvest season. Leaf breaking angle, leaf moisture content and time-lapse photography were investigated as methods to quantify treatment effects on wilting. The time-lapse photography helped reveal that wilting was most prevalent during the late afternoon, and that wilted plants sometimes began to recover after more than five days, apparently due to root re-growth. Root pruning was the only mechanical means that caused witling reliably during the first two years of testing, and even then the results were somewhat inconsistent. During the third year, a high-clearance tobacco sprayer was modified with a hydraulically actuated coulter disc in order to root-prune a large number of subjects