Unit 14
Read the text and do the tasks.
DRAINAGE (PART2)
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 a more efficient use of water, and one way of ensuring this in the future will doubtless be by using automatic control systems. Scientists have recently developed an experimental system at the Kirghizia Automation Institute in Central Asia. There an irrigation canal is parted into separate sections, and in each section a stable water level is maintained automatically. It is held that this system will eliminate disastrous local shortages of water by maintaining stable levels of water in the irrigation canals serving a large area. Such a system is very expensive, but it is claimed, doubtless under favourable conditions, that the capita! costs can be regained in less than two years. Ultimately, it is hoped that large canal systems will 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 a 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 a 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.
To summarize, an efficient, modern irrigation system should properly perform the following functions: 1) store water so that it is available insufficient 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 a system allows for the most efficient use of water and makes irrigation possible without soil erosion, saline, or alkaline accumulation, or waterlogging.
TASKS
Translate the following words into Russian. Be sure of their pronunciation.
areas, ruin, use, scientists, sections, shortage, cost, data, the humidity, the density, nature of the crop, requirements, saving,data
density
dispose
humidity
irrigated areas
reclaim areas
saline
shortages of water
soil erosion
stable water level
waterlogging данные
плотность(почвы)
удалять
влажность
орошаемые земли, площади мелиорировать земли соляной,солевой недостаток, недостача боды эрозия почвы постоянный уровень воды заболачивани
е
Unit 15
Read the text and do the tasks.
Irrigation
Irrigation is the artificial application of water to soil to assist in the production of crops.
In general, irrigation is most extensively practiced in arid regions where agriculture without it is not profitable but it is also used to lands of the semiarid regions to increase the yield and to special crops in humid regions such as rice, garden flowers and vegetables.
In fact, there are comparatively few regions where irrigation would not be profitable if it could be cheaply provided.
The surface of the Earth is composed of land and water, the latter being roughly three fourths of the area and not habitable by man. More than half of the remaining one fourth of land area is either too cold or too rocky for cultivation and the major portion of the rest is too arid for production of crops.
Thus, the area naturally available for cultivation is a very small proportion of the whole. Fortunately, man can increase the area for cultivation by artificially applying water to soil where nature fails to do this.
An irrigated region has certain advantages over a humid region. There is much advantage in being able to apply the water a
t
the proper time and in the quantity needed. There is much advantage in being able to stop application of water at will. The soils of arid regions are usually better supplied with the mineral plant foods which have not been washed out by excessive rains. Sunlight providing life and growth is more intense and constant in an arid than in a humid region. The yields under irrigation may be made larger and more stable, than under natural precipitation, provided sufficient care and skill are applied.
The choice of a method of irrigation depends upon topography, soil conditions, crops to be grown, value of crop products, available water supply and other factors.
Improper irrigation may waste large amounts of water and reduce crop yields. It frequently results in plant nutrients being leached from the soil. Excessive application of water causes high water table, w aterlogging and salinity of soil. This may be corrected only by the construction of expensive drainage systems. Very often drainage works are constructed together with irrigation development to discharge both excess water and excess salts.
TASKS
I. Translate the following words into Russian. Be sure of their pronunciation.
extensively, comparatively, cheaply, roughly, thus, naturally, fortunately, artificially, frequently, often, rapidly, downward, far.
application, surface, the Earth, advantage, the quantity, at will, growth, precipitation, care, skill, choice, water supply, yield, nutrient, drainage, layer, plant roots.
to assist, to increase, to provide, can, to increase, to apply, to fail, to supply, to wash out, to depend upon, to grow, may, to reduce, to result in, to leach, to cause, to correct, to construct, to discharge, to improve, to take place, to waste, to penetrate, to happen, to reach, to store, to remove.
artificial, arid, profitable, semiarid, special, humid, habitable, cold, rocky, major, available, able, proper, mineral, excessive, intense, constant, stable, sufficient, improper, expensive.КРАТКИЙ ГРАММАТИЧЕСКИЙ СПРАВОЧНИК
СПРЯЖЕНИЕ АНГЛИЙСКОГО ГЛАГОЛА В ДЕЙСТВИТЕЛЬНОМ ЗАЛОГЕ