The two most important aspects in reaping the tobacco crop are uniformity and adequate barn space. The best quality tobacco can be achieved only when the barns are filled with uniformly grown and harvested leaf. Ideally, the leaves in each barn should be of the same ripeness and from the same position on the plant so when the barn has been cured and unloaded, similar types of tobacco can be stored together until grading takes place. This makes the task of grading much easier.
Each year large quantities of leaves are left in the lands because growers do not have sufficient barn space for curing. The amount of leaf which is lost varies from year to year but is estimated that in some years as much as 13 million kgs are lost. Potential yields of 2 000 kgs/ha have been reduced to 1 200kgs harvested per hectare. Improved fertiliser use, better land preparation and the use of better varieties increases the yields of crops. The number of barns available for curing is usually the factor that decides the amount of tobacco that a farmer will market.
2. TIME OF REAPING
The lowest leaves on the plant will ripen when the plant reaches the extended bud stage of growth just before flowering. The first reaping should be taken at about the time of topping, and a general rule is:
Fast ripening areas ‐ reap just before topping; Medium ripening areas ‐ reap at topping; and Slow ripening areas ‐ reap just after topping.
This rule can be upset by weather conditions or by using too much nitrogen on the crop so as a consequence it delays the ripening of the leaves.
When the farmer decides that the time for reaping is nearly right, it is advisable to plan to put a few leaves from the bottom of the plants in a dark drawer, and check them for the amount of colouring which has taken place after 36 hours. Once the first leaf appears that is 50% coloured after 36 hours, reaping can start immediately. In general the decision to start reaping the crop is based on the experience of the farmer. Signs of ripening in leaves are:
A slight yellowing in the colour; which is not completely reliable as a guide as it can be caused by a number of other factors;
The leaves drop in relation to the stalk instead of pointing upwards; and
The slight stickiness which unripe leaves have seems to disappear and the ripe leaf seems to become smoother.
All the above are only general indications. The farmer needs to check the actual times taken for the leaves to colour once curing has begun in the barn.
|Table 1: Normal colouring periods which occur during curing in the barn are:
|Priming and Lugs
If the farmer finds that it is taking 90 hours to colour primings, then something is wrong and he is reaping the leaf too soon. The type of season can affect the above times and the farmer should investigate why the leaf is not taking the normal time to colour.
RATE OF RIPENING
The rate at which the crop will ripen will depend on the area in which the tobacco is growing and the kind of season. Weather or disease can make the crop ripen quicker or slower than is usual for a certain area. The rate of ripening will increase up to a peak and then decline again.
Table 2: Peak ripening rate is as follows:
|Leaves per Week
|Duration of Harvest
|Cool, higher areas
3. METHODS OF REAPING
The individual reapers decide which leaves are ripe and harvest only those leaves at each picking. Studies which have been carried out on farms have shown that individuals can vary enormously in their assessment of what is a ripe leaf and to be successful, the method requires very well trained experienced reapers.
The farmer assesses the ripeness of the leaves in the whole land and then tells the reaper to pick a set number of leaves from every plant. The number of leaves is usually two from each plant and these will be the two bottom leaves on the plant. The decision about what to reap is taken away from the reaper and he can speed up his work and increase productivity. The success of this method depends on the accuracy of the farmer’s assessment of the ripeness and uniformity of the crop in the land.
The main reaping methods used are:
The conventional method, using Mateppi (sticks) to hang the leaves on; The Kurt Machine, using strings; and
Using Tilita Clips or Manuclips.
THE CONVENTIONAL METHOD
The reaping team consists of 1 reaper and 1 waiter. Each reaper gathers a bundle of up to 80 leaves which he holds over his left arm with the butts of the leaves facing towards his body. He hands each bundle of leaves to his waiter who carries the bundle to the trailer parked on the contour. The leaves
are then tied onto sticks by the tying team consisting of 1 tyer and 2 waiters. The sticks of tied tobacco are then placed on the trailer for transport to the barn.
An alternative method is to tie the leaves onto the sticks at the barns, in which case the loose leaves are placed in crates for transport from the lands.
Using a figure of 102 leaves tied onto each stick, a good reaper taking one leaf from each plant will reap about 14 000 leaves in an 8 hour day. Taking 2 leaves from each plant he will reap about 24 000 leaves a day, but where the reaper has to select the leaves he reaps his output may be reduced by as much as 17%. The waiter should not have to walk more than 70 metres to the trailer and waiters should always wait on the same reapers. If more than 6 reapers are being used the team should be split on either side of the reaping road to avoid congestion. Points which should be watched by the supervisor are:
Leaving rows which are not reaped; Leaves left on the plant unreaped; Reaping green leaf; and
Reaping the correct number of leaves for the bundle or stick.
THE KURT MACHINE
This machine has been designed so that the reaper can reap the tobacco and also tie the leaves onto strings as they are reaped.
One waiter can deal with two reapers so that a team consists of 2 reapers and 1 waiter. The machine is made of tubular metal with a small wheel at one end and the other end attached to the waist of the reaper (see figure 3 on the following page). The reaper walks forward down the row of plants pushing the machine in front of him and reaping leaves from the row of plants on his right.
The waiter supplies him with strings cut to the right length, the loop is placed on the peg halfway up the shaft of the machine while the other ends are placed in the separate tension guides. Bundles or ‘hands’ of three leaves are tied onto the string and once the string is filled it can be tied off and pushed down the machine and another string started. The waiter can lift 1 or 2 strings of tied hands off the machine with a stick and carry them to the trailer parked on the contour. Tying 102 leaves onto each string, a good reaper will reap about 14 000 leaves a day taking one leaf from each plant and 16 000 leaves a day taking 2 leaves from each plant. This method does save labour because the leaves are reaped and tied by the reaper and no further tying has to be done. The waiter carries the tied strings to the trailer where they are loaded and transported to the barns for unloading and packing.
Figure 1: The Kurt Machine
Figure 2: Removing tied leaves from the machine
Figure 3: Tied leaves removed from the Kurt Machine
TILITA AND MANIPULAR CLIPS.
Both types of clips are made from 10 gauge wire. The Tilita clip is made in 2 lengths, 530mm and 775mm, and consists of a frame 25 ‐ 30mm wide with wire springs between the frames. The Manipular clip has an open‐ended frame to which spring clips are attached to one side only. When the short Tilita clip is loaded into the barn 2 clips are joined together. The long Tilita clip and the Manipular clip are suspended from cross poles or tiers which have been altered for the purpose. The Tilita clip is shown in the figure 4 on the following page.
Figure 4: A Tilita Clip
Using this method, a reaping team consists of two reapers and one waiter. The reapers should always carry a supply of spare clips as the row length being reaped should not be longer than 35 metres. The reaper walks down the row picking leaves from the plants on his right and holding the clip in his left hand. The butts of the leaves are placed in the clip between two springs and it is faster to tie the leaves in hands of 2 or 3 depending on how many leaves are being picked from each plant. For example, if 2 leaves are being picked they are tied in hands of 2. Once the clip is filled it is laid on the ground and the next clip started. The waiter picks up the full clips and carries them to the trailer. The short Tilita clips hold 45 leaves per clip and the long clips hold 72 leaves. The average output for a good reaper picking 2 leaves from each plant would be 11 500 leaves reaped in an 8 hour day using the long clip.
4. BARN ACCOMMODATION
As explained the limiting factor in tobacco production is often the barn space available to cure the crop. Farmers tend to grow more tobacco than they can handle during the peak ripening period. This results in leaves being left in the lands as they cannot be accommodated in the barn.
A farmer growing 40ha of tobacco with a plant population of 15 000 plants per ha. The total number of plants will be 15 000 x 40 = 600 000.
This farmer is in a warm area and his peak ripening rate is 3,3 leaves per week so the number of leaves to be reaped at the peak time will be:
3,3 x 600.000 = 1 980 000 leaves.
Assume that this farmer is using a standard barn with 6 tiers. This barn will hold 57 600 leaves. Curing time is 7 days including the 1 day required to unload the barn at the end of curing. His barn requirement during the peak period will be:
1 980 000 = 34 barns. 57 600
Working a 5 ½ day week he could fill 6 barns a day and 4 barns on the Saturday morning.
A standard estimate is that a barn 8 tiers high is required for each 1.5ha of tobacco grown. However, one theory is that as tobacco takes 1 day per tier to cure it does not pay to fill more than 6 tiers in a barn as the turnaround time is faster and the weight loss in the leaf is less because of the faster cure.
It is obvious that whatever system of curing is used, the farmer must know the exact area of tobacco planted and the plant population of his crop, so that he can work out his curing requirements accurately rather than by guesswork.