of equipment and methods already described that AERD developed. These harvest- 

 ing improvements are currently saving growers about 5 cents per pound. Even at 

 a 4-cent-per-pound savings, AERD estimates that 20,000 pints or 4 acres of blue- 

 berries would justify a mechanical harvesting unit. Equipment for a four-man crew 

 costs about $2,000. Amortized over 3 years, the annual cost would be about $800. 



AERD and Michigan State University have also done considerable work on 

 a continuous blueberry harvester that could reduce blueberry harvesting costs to 

 1/^ cent per pound by enabling 3 men to do the work of 120 handpickers. This 

 experimental unit, under development for about 4 years, has harvested over 90 

 percent of the ripe berries from experimental plots without damaging the plants 

 and without picking an excessive amount of unripe berries. 



The machine is self-propelled and has two large rotating spindles mounted ver- 

 tically on a steel frame. Each spindle has 160 wooden horizontal "fingers." In 

 operation, the machine straddles a row of blueberry plants with a spindle on 

 either side of the plants. The spindles rotate, and the fingers vibrate against the 

 plants, shaking the berries off into boxes that are at the base of the machine. 



Commercial models of this machine are not yet available. 



Dates 



Date palm trees are 30 to 60 feet high. Growers are finding it increasingly 

 difficult to get handpickers willing to work at such height. AERD, however, is 

 rapidly developing mechanical harvesting methods for dates that should relieve this 

 harvesting crisis. Although experimental, the methods were used last year to har- 

 vest commercially more than II/2 million pounds of dates. AERD achieved harvest 

 rates of 0.96 acres per hour (46 palms per hour) where at least one-half the 

 bunches on each palm were mature. 



One method utilizes a moving tower from which mature bunches from oppo- 

 site palms are harvested simultaneously. Workers, using specially designed vi- 

 brators, shake mature dates directly into bulk boxes as the tower moves between 

 the rows. 



The other method utilizes a smaller tower. One-half a palm is bunch harvested 

 at a time and the bunches are hauled in a trailer to a central point for shaking. 



The vibrators deliver a 3i/4-inch stroke at 600 to 1,100 cycles per minute and 

 can remove all the dates from a bunch in about 2 seconds. Two men feeding and 

 operating one vibrator can shake 450 bunches per hour. 



AERD made time studies of the two harvesting methods and concluded: (1) 

 Bunch harvesting is feasible, and (2) either method reduces total harvesting costs 

 relative to the handpicking method. 



Apples 



Preliminary studies by AERD and Michigan State engineers showed that it 

 might be feasible to mechanize the harvest of apples destined for processing. The 

 engineers mechanically harvested several hundred bushels of apples and placed them 

 in crates at a cost of approximately 3 cents per crate. Apples apparently shake 

 off the tree very easily. One grower shook off 200 bushels in an hour last year. 



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