5.Read the text and make up the plan to it:

TO SAVE THE SOIL FROM SALINIZATION

The chief culprits of salinization are sodium and magnezium salts. They are found deep in the ground, but along the capillaries, which abound in any soil, they are gradually drown with the salt liquor to the surface. The water then evaporates and the salt settles. Thus with every passing year it accumulates in the arable layer, forming a sparkling crust on the surface. And the plants begin to die – not of ordinary drought, but of what is known as physiological dryness. Try and slake the thrist with salt water.

In consequence, arable lands degenerate into waste lands, incapable of yielding crops. Thus salt inflicts colassal damage on agriculture.

In Pakistan salts have ruined more than 36,000 square kilometres of fields. In the 1970s a catastrophic situation developed: the peasants were losing their land at the rate of one hectare every 12 minutes. An alarming situation has also developed in some parts of some countries, especally in Azerbaijan, Central Asia and Kazakhstan.

Like Cures Like

Is there a cure? Scientists say there is. The cure is salt itself, but calcium salt – the widely known gypsum. It easily reacts with sodium, changing it into compounds that are harmless to plants. Like cures like, as they say. This method is now being widely used in the Ukraine, across the Urals and in Azerbaijan. On the desalinated lands, on which only recently no vegetation grew at all, comparatively good harvests have been obtained.

Armenian scientists on the other hand, have proposed treating salines, which abound in the Ararat Valley, with a one per cent solution of waste sulphuric acid which disarms alkalis and decomposes calcium and magnesium carbonates. As a result, the soils form the same gypsum.

However, not gypsum can overcome salinization. It is less effective in fact than some substances which are formed in the process of oil refining – a recent discovery made by Azerbaijan scientists. In their experiments these substances reduced the sodium content in the soil to one-quarter, and the plants revived before their very eyes.

The wastes from the manufacture of fodder yeast are as good as the oil wastes. Today biochemical plants supply them to the fields of Moldavia. Another effective remedy for salinization is iron vitriol derived from the wastes of metallurgical enterprises.

If soil salinization is halted, agriculture will receive substantial additional areas. This is why the problem preoccupies scientists and engineers. For example, associates of the Tselinograd Agricultural Institute have devised a special digging unit whose powerful rotors easily grind up the most dense saline layers.

At the Volgograd Agricultural Station similar results are being achieved by newly designed triple-depth ploughs which crush petrified soils, thereby allowing in air and water.

One new method is by the use of electricity. It forces the moisture to run along the capillaries and to restore the soil to life.

As the reader can see, traditional agricultural sciences are now being increasingly helped by non-traditionalones – petrochemistry, elecrochemistry, biophysics. Each contributes to the solution of the food problem which hangs over our planet like the sword of Damocles. According to UN data, half a million people in the world suffer from hunger or chronic malnutrition.

Slake the thirst –

Like cures like –

Iron vitriol –

Special digging unit –

Triple-depth plough –

The sword of Damocles –

6. Explain the mechanism of the soilsalinization.

7. Give the examples from the text about the aggravation and destruction of the fertile soils because of its salinization.

8. Using the text describe the ways of desalinization and improvement the soil fertility.

Lesson 82

9. Use the Present Simple, Past Simple, Present Continuous, Past Continuous of the verbs in brackets:

1. We ( to have) a postcard from them two days ago. They ( to say ) they ( to have) a marvellous time. 2. While she ( to stop) this morning, she ( to lose) her money. She ( not to know ) how. 3. They ( to announce) our flight. We ( to have) a problem. One of our suitcases ( to miss). 4. Who ( to speak) there? – I ( not to know). 5. He (not to smoke ). He ( not to smoke ) now. When he ( to be ) at the office yesterday, he ( not to smoke), he ( to work) hard. 6. When my sister ( to wash ) her skirt, she ( to find) a pound note in the pocket. 7. When you ( to learn) German? 8. We ( to go ) home now because it ( to be ) late.9. Who you ( to wait ) for? 10. Her car ( to break) down yesterday while she ( to drive) to work. 11.When and where it ( to happen)? 12. She always ( to wear) nice clothes for work. Today she ( to wear) a nice blouse and a dark skirt. 13. What she ( to watch) at the moment?. 14. I ( to see) my friend in the street yesterday, but he ( to run ) for a bus and he ( not to have ) time to speak to me. 15. What your son ( to do )? – He ( to study ) computer science. 16. what you ( to do ) at the weekend? 17. When she ( to open ) the door, a man ( to stand ) on the doorstep. It ( to be ) her uncle, but she ( not to recognize ) him because he ( to wear ) dark glasses. 18. Last night we ( to go ) to a cafe to meet our friends.