Reliable Protection for Plants

Farmers world over are concerned with problems of protecting food resources from numerous insects, animals, pathogenic agents and weeds. Plant protection in conditions of all-round agricultural intensification is an important reserve for increasing yields of farm produce. If no regular struggle on pests, p1ant diseases and weeds takes place, 20-30 per cent of harvest can be lost. Or, in other words, each fifth hectare of arable land would not be producing anything. That's why effective and bio1ogically safe methods of plant protection have become a world problem.

The protection of plants from pests, diseases and weeds has become one of the most important elements of plant growing processes and of increasing agricultural produce.

The protection of harvest and environment should based on a firm scientific foundation. A combination of methods – agrotechnical, biological, mechanical, chemica1 and quarantine contro1 – is being developed, which makes possible the protection of particular crops not from one, but from all types of pests, diseases and weeds. First of all non-chemical methods are used, chemical means being used only when extremely necessary.

The selection methods of harvest protection are most rational. There are, for example, disease and pest resistant types of cotton, potatoes, winter wheat. This method gives also great economy: every rouble spent on developing a new species is repaid 300 times over.

There are quite a few useful insects in nature. It is very important to preserve useful fauna and to increase the number of useful insects. For example, in some zones the increased sowing of grasses, especially, 1eguminous grasses, the sowing of nectar-bearing plants rapidly enrich the agricultural landscapes with usefu1 insects. Of great importance is international cooperation on exchange of useful species and forms of organisms.

The essence of the microbiological method is that plants have diseases. Re-searchers in many countries arenow looking for agents causing diseases of pests – fungi, viruses and bacteria – and methods of propagating them. Bacterial preparations were developed and are now being used in agriculture and forestry. Virus preparations are now being tested.

Chemical methods of harvest protection are likewise being improved. The tactics of using pesticides has been changed. The selectivity of chemicals, i. a. their ability to act only against definite types of organisms, has also increased. Moistening powders, concentrated emulsions which po11ute the air to a lesser extent are used more often. The contro1 over the safety of using pesticides should be of constant concern.

Rain-Making

 

Clouds in the air, even those big ans full of water vapour, do not help the farmers whose fields need rain, or the city people whose reservoirs are running low. To be of use, the clouds must become rain. Scientists think that clouds can be turned into rain if provided with more particles around which the rain drops can form.

All kinds of particles have been tried for artificial rain-making. One kind that seems to work is a chemical called silver iodide. Small particles of this chemical can be scattered from an airplane. They can spread very well among the particles of water vapour, so that only a small amount of this harmless chemical can help a large cloud to form rain drops.

Besides, dry ice can be used. Clouds can be cooled and possibly “dusted” by scattering bits of these crystals from a plane. The dry ice breaks up into cold crystals around which water vapour can cool and condense.

Of course, artificial rain-making will not work on every cloud. It seems to work only on clouds that need a little push, that are almost cool enough ot that have almost enough dust. But further experiments are being tried all the time, and some day it will be possible to have rainfall from any cloud, whenever we need it.

Dry ice can be used to start a chain reaction that will release a great deal of energy from hurricane clouds and so control the farm centres. Perhaps it will be able to force rain by cloud seeding at an early stage in the life of a hurricane and thus prevent the formation of the storm.

Although some scientists are very enthusiastic about cloud seeding with dry ice and a chemical known as silver iodide, others say such actions do not really change the weather. Some farmers consider that new methods of increasing rain are not producing the results needed. Cloud seeding holds great promise. So, there is good reason to believe that man may some day prevent hail and storms which produce crop damage, as well as increase rain supply to certain areas.

 

Age of the Earth

 

During the early part of the present century the Earth was thought to beat least 100,000,000 years old, possibly as much as 500,000,000 years old. The.former estimate of the minimum age of the earth was determined from а study of the ocean salts. Chemical analyses of ocean water indicate that salts are present there in the following proportions:

 

Sodium chloride. Magnesium chloride Magnesium sulphate Calcium sulphate Potassium sulphate. Magnesium bromide

77 per cent 11 per cent 5 per cent 4 per cent 2,5 per cent 0,5 per cent

 

These various salts in the oceans are carried there in solution by the streams, along with other land materials that are carried as sediments. All materials except the salts tend to become sediment at the ocean bottoms, while the salts accumulate in the ocean water. So if we can determine the total amount of these salts in the oceans and divide that by the total quantity contributed annually by the streams, the quotient willbe the time, in years, that this process has been going on, in other words, it will be the age of the oceans.

There are several chances for slight errors to be made in this computation since one cannot be sure that the conditions in the past were always the same as now. For instance, the area of the land regions was probably less in the past than now. If less land was above water the streams from it were probably not very swift so they carried less sediment and mineral matter in solution. Besides, some of the salt of the oceans may have come from the rocks on the shore lines and at the bottom, some of it we know was lost to the oceans when the rock salt beds were formed. Allowing for the variable factors as best we can - the age of the oceans has been estimated to be about 360,000,000 years. If this is the age of the oceans we know at once that the earth must be older since it had to come first to make а place for the oceans.Some scientists have argued that this first estimate is still too small since salt is being dissolved much faster now than in the past; hence they would make their estimate of the probable age of the earth four or five times greater.

 

 

10. 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

 

Nature Reserves

 

There are 140 natural reserves in the former USSR with a total area of 12 million hectares.

Signs prohibit vehicles from using the roads leading to the forest, to a place called Akste in Estonia. It is here that the country’s first ant reserve has been started. In an area of 190 hectares there are 1500 ant-hills.

Scientists are working on the artificial resettlement of useful types of ant in young forests in the northern part of the country. The first biospheric preserves have been created. In these forest reserves the ecosystem is studied in order to accelerate the development of new areas.

Central Fergana is a severe and wild land. Today much of the land has been cultivated and sown for crops. However, there are at least 600 square kilometres of land preserved as it used to be centuries ago. Here one may find towering sandhills and dunes, abandoned dried river beds, salt flats - takyrs, and many unique species of animal and plant.

Uzbek scientists want to preserve this island of desert in an untouched state for future generations.

Forest reserve made it possible to restore the population of rare species of plants and animals.

 

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