Highlands Intermediate School

07-0022
Introduction History   Current Developments   Future  Bibliography  Acknowledgments  About Us

History

    In the beginning, all agricultural tasks were done manually by humans.  Then farmers began using domesticated animals such as horses and mules to plow the fields and harvest crops.  The invention of the McCormick Reaper in 1831 was the breakthrough that brought about the use of machines in agriculture.[13]  Machines were used to increase productivity and yield and to reduce labor costs.  Today's farmers typically use tractors with attached implements that prune and spray pesticides and herbicides on plants.  They also have mechanical harvesters to harvest specific crops.[1]  However, the use of autonomous technology is limited because of the variable growth medium and the diversity of crops.  The type of crop dictates the kind of machinery that can be used.

   Our focus is on the use of technology in the coffee industry in Hawaii.  The two types of coffee cherries that are harvested are either ripe cherries, which are red or yellow depending on the species, and  overripe cherries, which are brown and shriveled.  In the past and even today, coffee is harvested by hand using a method called stripping, where the coffee cherries are just pulled from the trees, fall to the ground, and land on sheets.  The contents of the sheets are thrown into the air where the wind can carry away the debris.  With this method, 25% of the cherries picked are green (unusable).   Another way of harvesting by hand is to selectively pick only ripe cherries and to leave unripe ones on the trees to be picked later.[7]  This method is still used for coffee that is grown on rough lava fields and hilly areas like in Kona, Hawaii.[9]  Where mechanical harvesters are impractical, this method maximizes the amount of coffee harvested by not discarding any green cherries but is very labor intensive.  In Hawaii, laborers are paid between $0.40 - $0.65 per pound of cherries harvested.  The average amount of cherries harvested is 700 pounds per day, with about 2-3% of the cherries being green (unripe) and unusable.[1][9]

   The first attempts at mechanizing coffee harvesting took place in the 1960s in Hawaii, by using limb shaking techniques which gave a reasonable amount of ripe cherries but also included a high level of unripe cherries being harvested.  In order for mechanical harvesting to be profitable, the coffee plants needed to flower and bear cherries at the same time.  This was accomplished with the development of the drip irrigation system.  The first successful mechanized coffee harvester called the FMC-COCO coffee harvester was built in Brazil in the 1970s.  This was a very large “over-the-row” machine which harvested ripe and dried cherries in one pass. In the l980s, these harvesters were improved in Brazil and Australia using tine shakers.[5]  These harvesters are shaped like an upside down U tractor with large rotating drums equipped with an array of 200-300 fiberglass tines or “fingers”.  A harvester would have one or two of these cylinders attached on the sides of a “tunnel”.  It is driven over the coffee rows and the shakers knock off the ripe and overripe coffee cherries onto a conveyor belt that deposits the cherries into a bin.[4]  These harvesters have three wheels - two on one side and one on the other - which allow the harvester to make sharp turns at the end of each row of trees.  However, 30% of the cherries picked by this method are green.[1]  A new self propelled harvester was created later.  It could operate three times faster than the traditional models.  The new machine was also more selective in the cherries it picked and it did less damage to the trees.  The early “over the row” machines could replace an estimated 60-80 men, but this machine was even more effective.[5]

    Today's modern coffee farmer uses drip irrigation to distribute the exact amount of water and fertilizer to the plants. This system consists of hoses with punctures made at intervals of three feet or so.  Instead of wasting water and fertilizer, this system waters only the plants’ roots, not the weeds, reducing the need for herbicides and reducing human exposure to chemicals.  In addition to protecting our ground water system from excessive chemicals, it also ensures that the trees will flower and bear cherries at about the same time, making it more efficient for using mechanical harvesters.

    The tractors that trim the trees have a pruner attached that can turn and cut horizontally or vertically.  After the harvest, a driver will cut off about two feet off the top and trim the sides to keep the trees short enough for the harvester and to allow sunlight into the trees.[1]

    The tractors can also have a sprayer attached that can spray the fields with pesticides if the need arises.  However, some farmers such as Waialua Coffee do not spray pesticides and just use biological controls.[1]