Sprinkler irrigation

In sprinkler irrigation the water is sprayed into the air and allowed to fall on the land surface in a uniform pattern. This method came into widespread use because it could be adapted to most sites and crops.

The advantages of sprinkler irrigation, properly installed and operated, are:

Erosion can be controlled. Safe irrigation is possible on land too steep for the efficient use of other methods.

Uniform application is possible on all kinds of soil. On sandy soils that have high intake rates, (1) sprinkler irrigation distributes water better than other methods do.

Land preparation is not required. More land is available for cropping. Field ditches, corrugations, and dikes are not needed.

Small streams of irrigations water can be used efficiently.

The limitations are: rather high initial cost of installation. Much water may be lost due to evaporation and wind.

A constant water supply is needed for the most economical use of equipment. The water must be clean and free of sand and debris.

Tight soils, which have slow intake rates, cannot be irrigated efficiently in hot, windy climates.

Three types of sprinkler systems are used to irrigated farm crops: rotating sprinkler heads, fixed jets, perforated pipes. (2) Rotating sprinkler – head systems are the more widely used type.

Each rotating sprinkler head applies water to a given area. This area is governed by the nozzle size and the water pressure. Sprinklers in the low – pressure range (3) have small area of coverage. Medium – pressure sprinklers (4) cover larger areas and have a wide range of precipitation rates. (5)

High – pressure sprinklers cover larger areas, and precipitation rates are higher than for the moderate or medium pressures.

The sprinkler system includes the pumping plant to provide needed pressure, the sprinkler, the riser pipe, the main pipeline, and the lateral distribution pipe. Sprinkler systems are classified as (1) permanent installations, with buried main and lateral lines, (2) semipermanent, with fixed main lines and portable laterals, and (3) fully portable systems.

Sprinklers with perforated pipes deliver water through very small holes, drilled at close intervals along a segment of the circumference of a pipe.

Electric motors and internal – combustion engines are used to drive the pumps.

Notes

intake rates скорость поглащения

rotating sprinkler heads дождевальный аппарат с

вращающимися насадками

fixed jets неподвижные аппараты

perforated pipes перфорированные трубы

sprinklers in the lowpressure range низконапорные дождевальные

системы

medium – pressure sprinklers средненапорные дождевальные

аппараты

precipitation rates интенсивность дождя

Ответьте на вопросы.

Why did the method of sprinkler irrigation come into widespread use?

What are the advantages of sprinkler irrigation?

What types of sprinkler system are used to irrigate farm crops?

What does the sprinkler system include?

How are sprinkler systems classified?

Закончите предложения данными ниже словами.

The uniformity of distribution with sprinkler method is directly affected by …. 2. Portable mains are more economical when a sprinkler system is to be used on any of a number of …. 3. The permanent lines should be buried so as to be out of the way of farming …. 4. Water supplies, including source, quantity, and quality, should be investigated as an early step in the design of a ….

……………………………………………..

sprinkler system, operations, fields, wind.

Переведите предложения на английский язык.

Дождевальную систему следует проектировать так, чтобы полив производился с наименьшим расходом средств в течение года.

Ширина полосы, орошаемой перфорированной трубой, зависит от размера отверстий и напора воды.

Им надо будет использовать средненапорные дождевальные системы на тех полях.

Орошение дождеванием можно использовать почти для всех сельскохозяйственных культур (за исключением риса и джута) и почти на всех видах почв.

4.Перескажите текст с опорой на новые слова.

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