Unit 11 Crop Rotation Pretext Exercises

1. Give the Russian equivalents of the following international words.

selective, periodic, periodical, limit, unlimited, fixation, resource, economic, situation, effective, balance, organic, inorganic, productivity, natural, practice, rotation, correction, fixer, reason, condition, management

2. Find in the text nouns derived from the following verbs.

to till, to maintain, to alter, to penetrate, to add, to contribute, to know, to depend, to correct, to apply, to differ, to rotate, to improve, to cultivate, to distribute, to erose

Vocabulary list

1. crop rotation – севооборот

2. loss – потеря

3. tilth– состояние почвы

4. maintenance – сохранение, поддержание

5. alteration – чередование

6. barnyardmanure – навоз, органическое удобрение

7. to follow – следовать

8. penetration – проникновение

9. residents – остатки

10. drylandcondition – почва без орошения, богарные условия

11. residual – остаточный

12. sequence – последовательность

13. addition – добавление

14. to contribute – способствовать

15. shallow rooted – поверхностно-укореняемый

16. deep rooted – глубоко-укореняемый

3. Read and translate the text. Text a Crop rotation

Crop rotation is known to be a system of growing different kinds of crops one after another on the same land. A rotation may be considered good or bad depending on its effect on soil productivity. It should also be measured by its economic returns.

Continuous growth of the same crop has been found to result in the loss of organic matter from the soil, which is sure to have a bad effect on its tilth. The growth of grass pasture and deep-rooted legume crops in rotation is likely to correct this situation through maintenance of organic matter. As to nitrogen for non-leguminous crops, it may be provided by legumes included in the rotation. However, it should be mentioned that rotations are unlikely to supply other plant nutrients in which the soil may be deficient.

Legumes are more efficient in fixation of nitrogen on soils with low rather than high nitrogen content. For this reason, a legume is considered to be a better nitrogen fixer when two or more crops come between applications of barnyard manure. Naturally, legume crops are usually grown previous to crops that requirelarge amounts of nitrogen. Thus, increased yields of crops that follow alfalfa seem to result from the addition of nitrogen to the soil contributed by alfalfa crop. The preceding crop has an important influence on crop yields. So, in case when deep-rooted legumes are followed by corn, the latter may yield more as a result of better root penetration as well as due to nitrogen residents.

Crops sequences are very important under dryland conditions because of the difference in residual soil moisture left by various preceding crops. Thus, small grains yield more after corn than after small grains or sorghum.

Though the proper rotation is of great importance in farming, this practice alone is unlikely to produce maximum yields. For the highest yields to be obtained both crop rotation and fertilization are to be used.