An example problem on soil moisture

A cylindrical soil sample 10 cm in diameter and 10 cm long has been carefully taken so that negligible compaction has occurred. It was weighed before oven drying (1284 grammes) and after (1151 g). What soil parameters can be identified?

UNIT 3

Reading material

Text 1

Man and environment.

The ecological problem is the global problem of our time. Man is adversely affecting the environment and his activity is sometimes fraught with fatal consequences.

Human civilisation can inevitably perish as a result of industrial urban, vehicular and demographic pollution of the environment and the depletion of non-renewable natural resources.

It is becoming increasingly clear that man cannot and must not use tremendous power so carelessly, infinitely interfere in nature and radically try to change it, without taking into account possible negative affects of his economic activity.

Current ecological research shows that man, when over concerned with technicism, far from turning deserts into oases, can turn oases into deserts, threatening to destroy everything on earth if he continues exerting mostly uncontrolled impact on the biosphere.

In the 19-th century and even in the first half of the 20-th century material production did not require taking into account the consequences which man′s interference in nature may have in the distant future and it was not considered an objectively essential condition for the existence of the 20-th century such a consideration is becoming vitally important.

Hence man should carefully study the impact of his activity on various components of the surrounding nature. It is not only possible but necessery to transform the wild natural environment, which often has a disastrous effect on man

(earthquakes, typhoons, hurricanes, floods, droughts, magnetic and solar storms as well as radioactivity, cosmic radiation, etc.) into a safe environment suitable for man and meeting his needs. This means that the ecological problem is not simply the problem of man′s economic activity, but the problem turning man′s uncontrolled impact on nature into a purposeful and planned interaction with the latter.

The biosphere is a complex system and possesses enormous possibilities for self-regulation. The impact of industry on the biosphere is compensated for the inner resourses of homeostatic self-organisation.

Today, however, this impact has reached such proportions that the biosphere′s inner resources can no longer compensate for society harmful influence on the environtment, both on individual species and on all of life on earth without help from outside.

The task of the mankind is to protect our nature, scientific rational utilisation of the environment and to realize different measures on preserving a healthy environment.

All this means that at present there has arisen a pressing necessity to change the character of the interaction between man and nature.

The rational utilisation of resources and the conservation of nature are a matter of general state policy in all countries of this world.

The ecological problem can and must be solved by the efforts of all countries that is possible only in the conditions of peace and detente.