17. Write an annotation on the theme: «Seed germination».

18. Translate the text using the dictionary. Text c Seed and Germination

Ripe seeds are extremely resistant to both heat and cold. Some can survive the temperature of liquid hydrogen and some can bear, for a period that of boiling water. Moreover their respiration rate is so low that many can remain viable for many months in the absence of free oxygen. By contrast the vegetative parts of plants that are used for propagation – tubers, bulbs, etc. – are much more sensitive to heat and cold, and are dependent for survival upon a supply of free oxygen. Potato tubers, for example, are killed by a few degrees of frost, by heating to comparatively low temperatures, and, in perhaps two of three days, by submersion in oxygen-free water or in waterlogged soil.

It isa familiar fact that seeds of different species germinate at different rates.

Beets and carrots germinate slowly, cereals very fast. In many cases germination can be speeded up by wetting the seed before sowing. The length of time that seed will remain viable varies greatly from one species to another. Onion seed deteriorates rapidly, even under good conditions of storage. The seeds of many common weeds survive in the soil for long periods in some cases for several decades.

Unit 6 Classification of Field Crops Pretext Exercises.

1. Define the part of speech of the given words and give their Russian equivalents.

environmental, conditions, relatively, development, respiration, environment, uniformly, importance, evolution, special, productive, culture, selection, combination, favorable, growth, vegetative, function

2. Translate into Russian the following attribute combinations.

soil fertility increase, soil air circulation, mineral fertilizer application, higher protein content, plant parts, weed control, growth habit

Vocabulary list

1. ability – способность

2. growth habit – специфика (особенность) роста

3. annual – однолетний

4. barley – ячмень

5. bean – боб

6. biennial – двухлетний

7. to define – определять

8. edible – съедобный

9. fiber – волокно

10. flax – лен

11. grass – трава, злаковое растение

12. hemp – конопля

13. like – подобный

14. manure – удобрение(органическое)

15. to mention – упоминать

16. nitrogen – азот

17. object – цель

18. perennial – многолетний

19. to raise – выращивать

20. root crop – корнеплод

21. rope – веревка, канат

22. tuber-клубень

23. root crop-корнеплод

24. oats-овес

25. forage crop-кормовая культура

26. cotton-хлопок

27. rye-рожь

3. Read and translate the text using a dictionary. Text a Classification of Field Crops

The aim of the classification of field crops is to group them either according to their growth habit or according to their use.

On the first principle the crops are classified as annuals, biennials and perennials.

If you took a text-book of agronomy, you would find there the following classification of crops based on their use.

Cereal or Grain Crops.

If an agronomist were asked to define a cereal, he would say that it is the grass grown for its edible grain. Corn, barley, oats, rice, and rye to be mentioned as the main cereals raised by man.

Large-Seeded Legumes.

The principle legumes grown for seeds are field peas, field beans and soybeans. Sometimes the main object in growing legumes is to improve soil fertility for they are able to fix free nitrogen out of the air through the bacteria living on their roots.

Root Crops.

Unlike cereals, root crops as beets, for instance, are grown because of the food value on their roots. If they had not such an ability, they could not live and produce seeds the second year.

Forage Crops.

If you look for a definition of a forage crops, you will find that it is a crop grown because of its stems and leaves that are to be used in feeding livestock. Forage crops include all grasses cut for hay, legumes cut for forage, sorghum and corn fodder.

Tubers.

A tuber is a thickened underground stem. The most important tuber cultivated throughout the world is potato. We should make a great mistake if we called it a root crop, because its habit of life is quite unlike that of the root crop.

Fiber Crops

Several plants are grown because of their fiber which is used in making textile. Ropes and similar materials. The principle fiber crops are cotton, flax and hemp.

Crops for Special Farm Uses.

A special purpose crop may be any of the other types grown for a specific purpose. For instance, crops, like legumes, are grown to be plowed under for soil improvement and are called green manure crops.