Technological and Technical Development of Tobacco Drying

INTRODUCTION
Harvesting and curing (drying) affects the quality and even the yield of flue-cured tobacco.
Favorable curing conditions bring out the best properties of the leaves, but the final quality depends more
on the characteristics of the leaves at harvest than on curing. Optimum results in curing can be obtained
only with uniform, well-matured crops. But good leaves from the field may be partly or completely
spoiled by improper handling or loading practices, poor curing, or inadequate curing facilities. Quality
may be reduced after the cure by casing (conditioning) the leaves to high moisture content. Such leaves
"redden", and mold may develop in the storage piles (Collins-Hawks, 1993).
It is unambiguous that the good and economical curing is influenced by the growing technology,
preparation for curing and itself the curing technology. In addition to these things, we can reduce the fuel
consumption with different technical methods as making use of solar energy or regaining the waste heat.
Taking the Hungarian conditions into account I have been making the following research works and
experiments in realization of energy savings and improvement of the quality under curing flue-cured
tobacco:
− Influence of the preceding technology elements for the energy need of curing, and the best quality;
− Influence of the curing process for the energy scales;
− Development of tobacco barn constructions in decreasing of the energy consumption, and influencing
of the feature of end product;
− Applications of supplementary technical solutions for speeding up of the efficiency.
TECHNOLOGICAL DEVELOPMENTS
In Hungary You can find exclusively hand-harvested tobacco. There are a lot of troubles under
hand harvesting in the tobacco estates. Due to the shortcomings of the growing technology and the
weather conditions, the tobacco often ripens hardly or nearly at the same time.
The workers often harvest the unmaturated leaves and they mix the different levels because do not have
so much practice or are not interested in quality.
The harvesting influences not only the quality of the drying but also the energy consumption, because it is
necessary more energy to cure the green, unriped and mixed leaves - the experiences showed it.
The ripeness of the leaves at harvest is one of the most important factors affecting the final quality. For
best results, lugs should be overripe, the cutter, middle and tip leaves ripe.
Quality of the cure depends on the uniformity of the harvested leaves in ripeness and position on the
stalk. To attain such uniformity the plants must be uniform in size and age, and the field uniform in
fertility. Agronomic practices designed to create uniform fertility, minimize replanting, and maintain
uniform growths are highly important (Davis – Nielsen, 1999).
It should be harvested no more than two lugs, or no more than three cutter and middle leaves per plant.
They must leave four or five tips for the final priming, as a smaller number often ripen too slowly,
particularly in cool, wet weather.
It is best to avoid harvesting during wet weather, or for 2 or 3 days after a heavy rain. Under such
conditions leaves may temporarily revert to a less mature stage as a result of renewed nutrient uptake by
the plants. These leaves are difficult to cure, and the final quality is usually poor. The effect of wet
weather is most noticeable if the soil fertility is high or moisture has been deficient.
Leaves are often severely damaged at the time of picking. We must handle them carefully to avoid
breakage and bruising, particularly those primed early in the morning or in wet weather.
For reaching successful harvesting we have suggested a new tobacco growing technology with the help of
the ULT, and have been following with attention to the seedbeds, transplanting, cultivating and plant
protection.