Text 19

Active Vocabulary

TEXT 18

Active Vocabulary

ladle-ковш	frequency of impacts - частота воздействий, ударов
clamp diameter – диаметр захвата	digging depth – глубина копания
weight – вес	dredge – экскаватор
the equipment – оборудование	hydraulics - гидравлика

TOMORROW'S FARM MACHINERY

Designers have been making tractors more powerful to increase the speed of ploughing. But even a giant tractor like the K-700 A increases the width of the cultivated swath only slightly. By developing more powerful tractors, machines of 500 hp, for instance, the swath can be widened to six meters - - but what about the weight of such giant tractors? With today's ploughs a tractor expands its power not only on tilling but also on overcoming the resistance of the soil to the movement of the plough through it. After long searches, designers have developed a ploughshare having a more active reaction with respect to the engine. When moving across a field a plough loosens the soil by pushing its working parts away from the layer of earth. A tractor wheel or crawler track pushing away from the soil imparts a forward motion to the tractor. By attaching a cultivating tool to the rim of a wheel or to the crawler tracks you get a reaction cultivator. At present this principle is being applied in a mounted implement. One after another the working parts bite into the soil, loosening it, and at the same time push away from it helping the tractor. Thus, soil resistance (the reaction of the layer) is diverted into the direction of the movement instead of in the opposite direction, as in conventional ploughing. This considerably reduces the expenditure of energy in ploughing.

The use of reaction cultivation components is a highly prom­ising field. They make swaths as much as 12 meters wide. Despite the fact that they are propelled by light tractors with more powerful engines cultivation goes ahead faster. This unusual type of implement is still in its infancy. Scientists believe that in future a self-propelled plough will be developed.

We have mentioned only a few experimental models of farm machines. Some will prove their worth while others may possibly be rejected. That is a natural process as our scientists develop new, highly productive machines for farm fields.

arid - бесплодный	profitable - выгодный
cheap - дешевый	remain - остаться
compose - составьте	advantage - преимущество
disadvantage - неудобство	excess - избыток
sufficient - достаточный	skill - навык
choice - выбор

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