The Use of Solar Energy (2)
A solar plant to distil underground water has been operating for several years in the Central Kara-Kum Desert. Its initial capacity was three cubic meters of water daily. After the evaporator has been installed the area had been increased to one hectare, the capacity went up four-fold. This is enough to provide water for a large number of sheep.
One group of scientists from Turkmenian Academy of Sciences has made experiments on solar energy concentrators and gathered enough data on possible potential performance of solar electric stations generating cheap electricity in the Kara-kum Desert. As a result a solar furnace deve1oping temperatures of 3000 (in a sunray foca1 point) has been built. Electricity generated by this furnace costs a half of that generated by thermal stations. In the near future Kara-kum will become a large producer of cheap e1ectricity. The amount of solar energy per square meter here is equivalent to the energy got from burning 200 kg of the best coal.
The most efficient way of generating electricity from sunlight, however, seems to be the "solar battery". The first solar batteries were semiconductor crystals of germanium or silicon similar to those used in transistors. When the sun lights such a crystal, an electric current is generated. Since their first demonstration in 1954 the solar battery has been extensively developed and used in one of the greatest achievements of mankind – in space research on boards space ships, space rockets and sputniks. Solar batteries are very good for the purpose because of their 1ong 1ife.
In 1985 the first solar power-station will be put into operation in the Crimea. its power being 5 MWt – such was the power of the first Soviet atomic power-station in Obninsk.
North Gets Warmer.
It has been noticed that the climate inthe northern areas of the Earth is growing warmer. The average annual temperature in Spitsbergen has gone up by 12'C and in Greenland by 7'C. There are areas in Alaska and Scandinavia which were covered with ice several years ago, but are ice-free now. Why is this so?
There are two hypotheses. One says that the warming up process is produced by the formation of a new branch of the Gulf Stream. The other connects the warming upwith industrialisation. Factories discharge colossal amounts of carbon dioxide into the atmosphere. Even sma11 amounts of this gas in the atmosphere (0.03 per cent) act as a thermoregulator.
4. "Green revolution"
Scientific and technological progress is making itself felt more and more in agricultural production of the developing countries. It is not only by way of improving farm machines and implements, of more effective chemical fertilisers to the farmer, but also of progress in selection and genetics, what is called in the West "green revolution". The first problem which scientists want to solve is the problem of "straw-grain" balance. It is not good when the biggest part of the plant food from the soil goes not into the grain but into the straw. Now it is known that too muck fertiliser adds height to the plant, which is not what the grower primarily wants. Tall stands of grain are easier beaten down by wind and rain and this only makes harvesting more difficult.
Looking for the solution of the problem selectionists focussed attention on "dwarf" varieties of wheat. As a result the new varieties were deve1oped in Mexico, which solved the grain problem there. They proved to bethree times more productive than ordinary varieties, and adapted themselves very well to the conditions of tropical and subtropical areas where because of short day1ight hours wheat does not grow well. Mexico stopped importing grain and since the mid-sixties has herself been exporting about a million tons annually.
Many countries, primarily those of tropical Asia, took an interest in the new varieties, In the course of 3-4 years, the hybrid wheats became a leading grain crop in this area. In India the "Mexican" varieties, further improved by local selectionists, were planted over an area of 4,000,000 hectares.
Scientists now turned their attention to another cereal that has been the main food for centuries – rice. In 1962 an International Rice Research Institute was founded on the Philippines. The local climate, in which three harvests a year can be grown, made it possible to carry on selection work very quick1y. By 1965 two dwarf varieties of rice grew on farm fields. Besides doubling and trebling the yields, they matured a month earlier than the usual varieties of rice. Later, sti11 more rapidly maturing hybrid was grown which requires only 90 days from planting to harvesting instead of the 140-180 days for ordinary varieties.
Selectionists working with maize and millet also succeeded in increasing yields.
The developing countries have worked at the problem with energy. In the United States it took 15 years to get а hybrid maize evolved into large-scale cultivation. The scientists of young developing countries themselves have contributed very much to the further improvement of imported varieties. In India, for instance, wheats with heightened immunity to plant diseases and highest protein content were obtained in the period of five years on the country's farm fields.
Here are some of the initia1 (first) results of the "green revolution". Some developing countries already are close to being able to meet their own grain requirements.
Environmental Protection.
Nature conservation is a task tackled in a comprehensive manner over large regions. The Moscow region may be taken as an example.
In the parks of Moscow you can hear nightinga1es sing, Swallows, which are very difficult to please in environmental terms, are building their nests in the Kuskovo park. Wild ducks are living and breeding on the ponds in the capita1.
Despite the impressive growth of the city's industrial potential and an increase in the number of cars – up to 400,000 at rush hours – the city air is c1ean. Control over the content of toxic substances in exhaust fumes has been introduced and some motor vehicles have switched to liquefied gas. Moreover, many motor vehicles have been fitted with neutralizers.
Many fume and dust trapping insta11ations have been builtor modernized in Moscow. Some of Moscow's flats are heated by heating plants using natural gas. Industrial enterprises which polluted the environment have been moved beyond the city limits.
The forests around Moscow are well kept and their area is growing. In the Moscow region more than 38 species of anima1s and a1most 100 bird species may be found, including elks, wild boars, foxes, hares, squirrels, hazel grouse and black grouse. Aurochs brought from Byelorussia have settled in the region.
All radioactive liquids and gases, spent uranium and other waste materia1s discharged by atomic power-stations are treated at special safety stations by physical, mechanical and chemical methods. The concentration of radioactive substances in this waste material is reduced to the prescribed safety level. Radioactive sediment is mixed with concrete or bitumen, placed in containers and buried deep underground.
Nature does not recognize national boundaries. The ecologica1 crisis is а threat to all. The atmosphere in the Scandinavian countries is affected by smoke from French and German factories while the Siberian forests he1p Korea and Japan to breathe. Measures to protect nature in our country affect neighboring countries and vice versa.
Controlled Environments
Man cannot quietly adapt to the existing environrnenta1 conditions of his agricultural areas. He has altered these conditions by clearing the land of unwanted species, controlling weeds, increasing soil fertility and providing water by means of irrigation. Man has also been actively developing crop varieties which are better adapted to various environments.
With the ever-increasing demand for food, knowledge of plant response to the environment has become more and more important. Greenhouses or glasshouses, plant-growing chambers and phytotrons are used to obtain answers to many problems now facing the agricultural science, the most important of them being the determination of maximum yield that is possible and optimum conditions for maximum growth.
The controlled-environment rooms have become very important in biological research. They are important in obtaining biological knowledge to improve agricultural practices and produce.
Controlled environments for plant growth serve several purposes:
1) to determine how environmental factors affect plant development; what factors should be controlled and when such controls are useful and/or necessary during the life-cyc1e of the plant;
2) to establish the maximum yield that farm crops can be expected to produce;
3) to supplement field research in plant breeding and the introduction of new crops;
4) to provide conditions useful for biochemical and physiological investigations which can give necessary information for solution of agricultural problems;
5) to understand how environment affects pathogenesis, and some others.
Much investigation of environment control is stil1 carried out in the field through irrigation, weed control, fertilisation and frost prevention.
Plant-growing chambers and phytotrons provide most ideal conditions for plant growth, but now they are not used for commercial production but only as a means of research. Growth chambers, and especially phytotrons, provide a rapid means for determining the growth potential of plants.
The term plant-growing chamber is used to describe all kinds of controlled-environrnent facilities. There are many different types of plant-growing chambers. Some of them are large and man can work inside the chamber. Such chambers are known as reach-in or walk-in cabinets. Some are small. In this case man can work with his hands in. There are special-purpose chambers such as dew chambers, seed germinators, photoperiod rooms and others.
Chambers are usua11y constructed so that they can be used for a specific research purpose or for a particular kind of plant. There are chambers for carrying out plant disease investigations, for photosynthesis study, for soil atmosphere studies, for air-pollution research.
The chambers can be naturally-lighted or artificially lighted. The major changes that have taken place in plant growing chambers have been a resu1t of lighting systems. Different types of lamps are used in chambers. Fluorescent lamps are considered to be exce11ent light sources that provide good plant growth. Fluorescent lamps are usually mounted vertically on the walls as well as on the ceiling. During the last years some other kinds of lamps were suggested. They are sodium lamps and Xenon ones. Experimental data on the biological effectiveness of the former are at present inadequate to establish their role in controlled environments. As far as the Xenon lamp is concerned, its use is limited due to high costs as well as to some technical difficulties.
Temperature and humidity are also controlled in all types of plant-growing chambers.
Phytotrons are the most complex form of controlled environments, since they are composed of many types of plant-growing chambers. Artificially- and naturally-lighted plant-growing chambers and cabinets may be used in conjunction with seed germinators, dew chambers, photoperiod rooms and other controlled environments.
The keyfeature of a phytotron is the method of operation. Various forms of controlled-environment rooms, such as greenhouses, growing chambers, germination rooms, etc. are accumu1ated in one location so that plants can be moved from one environment to another. A phytotron is
therefore so organised that many combinations of environmental factors can be studied simultaneously and it is this organisation that defines the phytotron. Phytotrons differ both in design and in their research purposes.