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标题: Agricultures Fantastic New Machines [打印本页]

作者: yunyou    时间: 2007-9-21 19:04     标题: Agricultures Fantastic New Machines

Agriculture's Fantastic New Machines Hard work can be fun --- to watch! Last summer I stood at the edge of a huge tomato field in California. I started at an odd machine, sailing like a ship across a sea of plants. In its front was a gaping hole. As this strange machine moved forward, an endless stream of vines heavy with tomatoes flowed into the hole. And empty vines poured out the rear.
On top of the craft sat two rows of six workers, each facing inward. Working rapidly, they picked out the bad fruit from the tomatoes that rushed past them on moving belts. This work is called culling. A steady, red waterfall of ripe tomatoes poured into a kind of cart that was being pulled alongside.

With this remarkable machine, one driver and 12 cullers can pick in an hour ten tons of a new kind of tomato. Without this invention, it would take 60 men to do the job!

A farmer knows that picking a crop by hand is slow, hard work, and finding workers is even harder. But agriculture's fantastic new machines are helping speed food from plant to plate, from seed to table.

Seed Planter at Work
At the Sea brook Farms in New Jersey, more than 35 square miles of crops are grown. Watch the tractor-pulled seed planter as it sweeps back and forth on a 225-acre field of green beans. It plants up to 400 miles of rows a day.

A few years ago this planter would have been following another tractor-drawn machine that fertilized the field. A couple of times during each growing season gangs of field workers would labor, pulling weeds between the plants.

Now a single tractor driver handles all these jobs. His planter places the seeds the proper depth into the ground and covers them with earth. The planter also squirts a liquid fertilizer on each seed. Between each two seeds it squirts weed killer that will keep weeds from springing up during the entire growing season of the crop.

Shake Up, Fruit Down
In some orchards where peaches are grown for canning, a tractor with a long metal arm drivers up to a tree. It clamps fingers around a limb and gives it a frantic shaking. As the peaches rain down, they land in a catching frame covered with canvas, much like a trampoline.

The fruit bounces down the sloping canvas to a conveyor belt. This moving belt carries the peaches up into a wooden box. With shaker and catching frame, three men can fill three ten-ton trucks in a single day.

Potatoes on the Move
After a crop of potatoes is picked, an assortment of automatic devices takes over. I watched trucks dump eight-ton loads of potatoes into a flume, a chute filled with rushing water. The water flushes off the mud and streams the potatoes are prepared for shipping.

Inside, the shed looks like a tangle of tiny roads and highways. Thoussands of potatoes charge over and under one another along the crisscross of conveyor belts. Jets of specially treated water continually spray at him. Heated air blasts at them Rollers and nylon brushes spin them onto shaker screens that separate them by size.

Next, the potatoes drop into bags. The bags are weighed and pushed along rollers to be packed into boxcar,but it is a wild ten minutes!

Crazy Plants, Crazy Problems

Not all plants cooperate willingly with the farmer's machines. Seeds planted in the same field at the same time ripen at different times. The only way to tell a ripe head of lettuce id to look at it and squeeze it. And now there is a machine to do even that!

The "lettuce-tester" machine crawls along a lettuce row with a little roller sticking out a few feet ahead. The roller bobs up and down over the lettuce heads. When it moves over one that feels right, it sends a signal back to the "picking machine." As this unit comes alongside, a cutter bar darts out and slices the stem. Then the head of lettuce is grasped in the claws of a device that tumbles it onto a conveyor belt.

Some nuts are hard to crack, but there is a machine that can deal with even this problem. A squirt of gas is shot into the shell, which is passed through a flame that bursts it open.

If ever there was an "impossible" crop to harvest, tomatoes are it. The fruit ripens a few at a time, over a period of two months. The vine is an octopus like mess of tentacles. When run through a machine, these hair-like growths wrap themselves around moving parts. Worst of all are the roundness and the softness of a tomato. Drop a ripe one and-splott!

What could be done about this uncooperative fruit? Two professors decided not only to design a new machine but also to grow a new type of tomato!

One professor experimented with ideas for shaking, combing, raking or stripping the fruit off the plant. The other professor was busy changing the fruit's shape. He started by growing a longer and smaller tomato. Then he developed a smaller tomato vine. Finally he grew a type of plant on which 90% of the fruit ripens at the same time.

The first result of the professors' work was a new breed of canning tomato. It was named VF-145. The second result wasthe machine described at the beginning of this story.

Not all the crazy problems that plants present have been solved yet. Strawberries, for example, are delicate and are hidden under their vines. They are always "ready-ripe-and-rotten" within a few hours. And olives refuse to cooperate with the tree-shaking machine. They cling to their long branches and wave back at the machine.

Expert continue to struggle with these problems. Meanwhile, the farmer is delighted with mechanical devices that pick tomatoes, shake peach trees and cut off heads of lettuce. In the future, what kinds of clever contraptions will help him with his harvest?






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