Text C. WEEDS

Weeds are found on every farm and in every field. It is impossible to find land completely free from weeds. There are many ways in which weeds may be spread. They are mostly transported by seed, by water, by wind and the animals. Many weed seeds can live in the soil for some years, making the control much more difficult. Weeds reduce growth and yields of cultivated crops as they take away their food water. The best time to kill most weeds is before they can be seen and the best way to kill them is by means of cultivation. Good plowing is the basis of weed control. Rotation of crops is another method. Each type of crop is associated with certain weeds, so if the same crop is grown for many years, this will increase the number of weeds. By crop rotation many weeds are controlled. Chemical weed control is a rather efficient method, too. Spraying machines are used to apply different weedkillers. There exist weedkillers that kill only certain plants or groups of plants. They are called selective weedkillers and can be used to kill weeds growing in many crops. Nowadays hormone weedkillers are produced which kill the weeds by stopping their growth. Hormones can kill underground parts of weeds, and sometimes they remain in the soil for some time after spraying. At present hormones which can kill many kinds of weeds are being developed.

3.3. TEST-5

Choose the proper definition for each term:

Complete the sentences with the necessary words:

6. … is typical of almost anything in nature.

a) excess

b) variability

c) ground

7. All soils vary in ….

a) fertilizer

b) fertility

c) wheat

8. How many approaches to fertilization are used?

a) one

b) two

c) three

9. An … of nitrogen can result in an undesirably high level of protein in wheat.

a) excess

b) lack

c) absence

10. Which system of fertilization results in maximum possible crop production?

a) fertilize at a high rate

b) fertilize at a low rate

c) neither

11. To select the proper chemical for … one should know specific weed species.

a) rainfall

b) planting

c) weed control

12. To apply herbicides correctly one should know weed species, stage of growth and ….

a) life cycle

b) food water

c) hormone

13. If several herbicides are used at a time, they must be … thoroughly.

a) caused

b) affected

c) mixed

14. … may affect herbicide spraying.

a) volatile herbicide

b) organic matter

c) strong wind

15. Weeds … growth and yields of cultivated crops.

a) assist

b) reduce

c) develop

16. Planting potatoes can be … any time during April and May depending on the soil condition.

a) do

b) did

c) done

17. … triticale as well as wheat grown mainly for pasture?

a) does

b) is

c) has

18. Triticale is usually … with wheat in quality, yield and other aspects.

a) compare

b) compared

c) comparing

19. In upland areas, planting … be done at such a time so that young plants are not damaged by late frost.

a) is

b) has

c) must

20. Best quality tubers …obtained when seed potatoes was harvested in late autumn.

a) were

b) are

c) have

21. Potato tubers will keep better if they are … to remain on the ground after digging for 1 or 2 hours.

a) allow

b) allowed

c) allowing

22. There are herbicides that should not … placed on the surface of the soil.

a) be

b) are

c) to be

23. At what stage … better?

a) weeds are controlled

b) are weeds controlled

c) are controlled weeds

24. No herbicides are effective unless they … applied in proper rates.

a) are

b) was

c) had

25. Under no-plough system a greater amount of chemicals … needed to control weeds.

a) will have

b) will be

c) will do