V. Найдите в тексте абзац, в котором рассматриваются преимущества комбинированной оросительной системы.

VI Расположите следующие слова и словосочетания в порядке, отражающем процесс движения воды по комбинированной оросительной системе:

field furrow, canal, take-off, delivering pipe-line, flexible watering hoses, roots of the plant

Vll. Сделайте краткий пересказ текста “Automationin1rrigation Methods”,

Drainage

Getting the water onto the land is only part of the problem that faces the farmer; of almost equal importance is the disposal of water after use. Тоо much water in the soil can be worse than not enough, while inadequate planning and improper irrigation frequently result in salination and waterlogging. Salination occurs because the roots of the plants absorb the irrigation water but exclude most of the salt it contains. The salt remains in the soi1 zone upon which the plant depends for growth and eventually renders the soi1 sterile.

То prevent catastrophic consequences, which are too common in many areas, there rnust be complete and efficient control of irrigation water. It is difficult to overestimate the harm caused by salination and waterlogging; indeed, reclaiming lands ruined through faulty or misused irrigation is almost as -important as bringing new 1ands under irrigation for the first time.

If reclamation is to be successful, the basic problem is to lower the water-table so that it is kept below the root zone. This may be achieved in а number of ways: а grid of deep ditches may be laid along the boundaries of the fields, or lines of tiles 1aid in the fields to collect the water and convey it to а co11ector ditch.

Many areas, particularly in the arid parts of Asia, cannot be conveniently or economically recovered by normal drainage processes. One method of restoration in these circumstances requires the installation of tube wells for pumping the areas to be drained and using the pumped water for further irrigation elsewhere. This method is of growing importance in some countries, but it can be very costly, sometimes proving more expensive than bringing in new irrigated areas. The use of tube wells for this purpose is like1y to increase when cheap hydroelectric power becomes avai1able on а larger scale.

However, it is necessary not only to reclaim areas that have already been spoiled, but also to prevent further ruin. This can only be done by а more efficient use of water, and one way of ensuring this in the future wi11 doubtless be by using automatic control systems. Scientists have recent1y developed an experimenta1 system at the Kirghizia Automation Institute in Central Asia. There an irrigation cana1 is parted into separate sections, and in each section а stable water 1evel is maintained automatica11y. It is held that this system will eliminate disastrous local shortages of water by maintaining stable Ievels of water in the irrigation cana1s serving а large area. Such а system is very expensive, but it is claimed, doubtless under favorable conditions, that the capital costs can be regained in less than two years. Ultimately, it is hoped that large cana1 systems wi11 be controlled by computers. Data on the condition of the irrigated areas, including the humidity of the air and soil, the density of the soil and the nature of the crop, would be fed into а computer, which would then estimate the water requirements for given areas and select optimum water regimes for each section of each canal and for the system as а whole. The first results of recent experiments along these lines suggest that they bring about considerable savings both in the consumption of water and in the cost of irrigation.

То summarize, an efficient, modern irrigation system should properly perform the following functions: 1) store water so that it is available in sufficient quantities whenever required; 2) deliver water to all parts of the cultivated area, in amounts needed to meet crop demands during peak use periods; 3) provide complete control of water; 4) divide water into required amounts for use in different fields; 5) dispose of waste water after use; 6) allow for the free movement of farm machinery. Properly utilized, such а system allows for the most efficient use of water and makes irrigation possible without soil erosion, saline or alkaline accumulation, or waterlogging.

Упражнения

I Определите значения следующих слов по сходству с однокоренными

словами в русском языке:

to utilize, to summarize, catastrophic, automatic, есоnomic, experimental, economically, automation, accumulation, section, capital, computer, optimal, optimum

11. Определите, к каким частям речи относятся следующие слова, и переведите их:

to overestimate, to misuse, humidity, density, useless, doubtless, improper, inadequate, particularly, successful

III. Найдите в тексте:

1) существительные, соответствующие следующим глаголам:

to compute, to consume, to erode, to move, to accumulate, to restore, to require, to reclaim, to demand, to drain, to dispose, to pump, to use, to experiment, to insta11, to grow

2) глаголы, соответствующие следующим существительным:

maintenance, storage, delivery, performance, reclamation,

division, elimination, disposal, selection

IV Укажите, какие из следующих прилагательных могут сочетаться по значению.с существительным drainage:

efficient, complete, adequate, arid, proper, humid, successful, expensive, automatic, convenient, normal, favorable

V. Найдите в тексте абзацы, в которых содержится описание различных способов понижения уровня грунтовых вод. Выпишите предложения, в которых дается характеристика наиболее эффективного способа.

Vl. Найдите в каждом абзаце текста предложение, выражающее основную мысль абзаца.

Vll. Сделайте краткий пересказ текста “Drainage”.

VIII. Прочтите без словаря следующий текст. Ответьте на вопрос, поставленный в заголовке:

Who Demands а Purer Water?

Since rain-water is very good for plants, and sea-water is very bad, we may ask whether there is some intermediate kind of water that the p1ant wil1 just tolerate. The question is likely to be of great importance in arid regions where the only available irrigation water comes from underground sources. During its long staying and slow movement deep below the surface, the water dissolves minerals' salts from the rocks that surround it. Suppose this mineralized water is now offered to (1) human beings, (2) animals, (3) food-plants, and (4) machines; how will they respond?

Меn wil1 drink water containing 1 part in 1,000 of dissolved salt, animals wi11 drink water that is much more saline, while food-plants demand а purer water.

This is not only because the salt is harmful to the plant but mostly due to the fact that after long periods, the land irrigated with saline water becomes saturated with salt and in the end becomes unfit for cultivation. The water itself drains away or is transpired and the salt stays in the ground. The irrigation water should not be more than about one fifteenth as salt as sea water, its mineral content should be much less than 1 part in 1,000. But if the local climate and the nature of the ground are favorable, some plants will grow on water that is much more saline than this.

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The Use of Solar Energy

     The Sun possesses a limitless amount of energy and mankind is looking for different ways to uti1ize it because time will come when we shall not have any other energy but the Sun's. Coal, oil and gas will be used up.

The most primitive device for using the heat of the Sun is the gardener's greenhouse. Usually this device consists of the solar water-heater placed on the roof of the greenhouse and covered with g1ass. The water circulating in it is heated by the Sun, then pumped into a hot-water tank warming the greenhouse. Such a 100 square-metre greenhouse was built in Turkmenia: solar energy is used to grow flowers and vegetab1es all the year round on a commercial basis.

Solar energy is used both for heating houses and for cooling them. For example in Florida many "solar houses" have been built. In these houses some material is used to take it and to keep heat of the Sun and to give it away gradually as required. Water is a good material for the purpose, but Glauber's salt  is even more efficient. It melts at atemperature of 90' talking in a large amount of heat which it gives back when it turns into crystals again. Another interesting material is gravel in the walls of the house, which it keeps warm on sunless days. In Ashkhabad there are many houses cooled with the help of solar energy. Ten children's institutions in the same city have been equipped with showers. They look like any other showers, except that water for them is heated by the Sun to a temperature of 70' C on the south sides of the houses. As Turkmenia gets more than 180 sunny days each year (as many as Egypt and California) solar showers can be used from early spring till late autumn.