Text 8 how soils are classified
Pedologists classify soils according to the characteristics of a polypedon. The Soil Survey Staff of the United States Department of Agriculture uses a system that consists of 10 orders (groups) of soils. They are alfisols, aridisols, entisols, histosols, inceptisosl, mollisols, oxisols, spodosols, ultisols, and vertisols.
Alfisols develop under forest and grasslands in humid climates. Some agricultural soils are alfisols.
Aridosols occur in dry regions and contain small amounts of organic matter. Desert soils are ardisols.
Entisols show little development. They resemble the parent material and occur in many climates.
Histosols are organic soils. They form in water saturated environments, including swamps and bogs.
Inceptisols are only slightly developed. They are more common in subhumid and humid climates, but also occur in most other kinds of climates.
Mollisols develop in prairie regions. They have thick, organically rich topsoils.
Oxisols are the most chemically weathered soils. They have a reddish color and occur in tropical regions.
Spodosols contain iron, aluminum, and organic matter in their B horizons. They form in humid climates.
Ultisols occur in warm, humid climates. They are moist, well-developed, acid soils.
Vertisols form in subhumid and arid warm climates. They develop wide, deep cracks during dry seasons.
TEXT 9 SOIL CONSERVATION
The soils of farmlands, grazing lands, and forestlands provide many products and recreational areas. Soil conservationists work to ensure the wise use of these soils.
Wise use of farmlands involves maintaining a high level of nutrients and organic matter in cultivated soils. Farmers add organic matter to the soil by plowing under certain green plants. They also add fertilizers and rotate crops to replace nutrients that leaching and growing plants remove. In addition, farmers plow and plant their fields in ways that control erosion.
Grazing lands that have been overgrazed also suffer from erosion. Overgrazing decreases the amounts of plant life and organic matter in the soil, and the soil erodes easily. Ranches conserve grazing lands by limiting the time that their herds graze in one area.
Forestlands also must be protected from erosion. In some cases, foresters leave unusable branches and other parts of trees on the forest floor to add organic matter to the soil. They also develop large groups of trees whose roots protect the soil by holding it in place against wind and water erosion.
TEXT 10 SOIL AND ITS MANAGEMENT
Good farming means proper use of many factors such as natural conditions, land, crops, livestock, machinery, fertilizers and some others. All these factors have to be put together to make the farming system work successfully.
One of the most important points to be taken into consideration in farming is the soil which is known to be a natural resource that supports plant life. It is a mixture of particles of rock, organic materials, living forms, air and water.
During his entire existence upon the Earth man has depended upon the soil either directly or indirectly. Grain, fruits and vegetables are food products obtained by man directly from the soil. Domestic animals consume grain and forage produced by the soil and in turn supply people with meat, milk, eggs and other products used for human food. These are the products obtained from the soil indirectly.
Some good clay and loamy soils are naturally poor. Various factors that make up soil fertility are moisture conditions, plant food, and soil structure. All these components may be regulated by proper management of the soil.
Soil management is the science of tillage operations, cropping practices, using fertilizers, lime and other treatments conducted on, or applied to, a soil for the production of crops.
Plant growth and yields can be increased by applying certain recommended soil management practices, liming, fertilization and irrigation producing, as a rule, immediate yield increases. Good soil management results in better yields and lower cost per unit of production. Fertile soils produce plants that are less affected by diseases and less likely to be attacked by insects. In this case small losses of crops result.
Some time ago attention was centered on such macroelements as phosphorus, nitrogen and potassium. Now, it is well known that in addition to primary plant food elements mentioned, so-called secondary elements (calcium, magnesium, and sulphur) as well as microelements or trace elements (boron, copper, manganese, zinc, and molybdenum) may be highly important for crop yields, for livestock and human health.
That is why all farmers should make soil tests in order to determine whether any essential elements are lacking in the soil and to determine the rate of fertilizers to be applied.
TEXT 11 WATER
Water is the most common substance on earth. It covers more than 70 per cent of the earth’s surface. It fills the oceans, rivers, and is in the ground and in the air we breathe. Water is everywhere. Without water, there can be no life. In fact, every living thing consists mostly of water. Your body is about two- thirds water. A chicken is about three- fourths water, and a pineapple is about four- fifths water. Most scientists believe that life itself began in water – in the salty water of the sea.
Ever since the world began, water has been shaping the earth. Rain hammers at the land and washes soil into rivers. The oceans pound against the shores, chiseling cliffs and carrying away land. Rivers knife through rock, carve canyons, and build up land where they empty into the sea. Glaciers plow valleys and cut down mountains. Water helps keep the earth’s climate from getting too hot or too cold. Land absorbs and releases heat from the sun quickly. But the oceans absorb and release the sun’s heat slowly. So breezes from the oceans bring warmth to the land in winter and in winter and coolness in summer.
Throughout history, water has been people’s slave – and their master. Great civilizations have risen where water supplies were plentiful. They have fallen when these supplies failed. People have killed one another for a muddy water hole. They have worshiped rain gods and prayed for rain. Often, when rains have failed to come, crops have withered and starvation has spread across a land. Sometimes the rains have fallen too heavily and too suddenly. Then rivers have overflowed their banks, drowning large numbers of people and causing enormous destruction of property.
Today, more than ever, water is both slave and master to people. We use water in our homes for cleaning, cooking, bathing, and carrying away wastes. We use water to irrigate dry farmlands so we can grow more food. Our factories use more water than any other material. We use the water in rushing rivers and thundering waterfalls to produce electricity.
Our demand for water is constantly increasing. Every year, there are more people in the world. Factories turn out more and more products, and need more and more water. We live in a world of water. But almost all of it – about 97 per cent – is in the oceans. This water is too salty to be used for drinking, farming, and manufacturing. Only about 3 per cent of the world’s water is fresh (unsalty). Most of this water is not easily available to people because it is locked in icecaps and other glaciers. By the year 2000, the world demand for fresh water may be double what it was in the 1980's.’But there will still be enough to meet people's needs.
TEXT 12 “How A Plant Lives”
I. Read and translate the text:
Trees are woody plants, growing with a single stem. They are the largest members of the plant world, ranging in height from 20 to 300 feet or more, according to species and conditions of growth. Trees may be said to consist of three parts:
- the roots which hold the tree in place and take up from the soil water and certain mineral substances needed for the trees growth;
- the trunk or stem which supports the crown and supplies it with water and food from the roots; and
- the crown. In this part the most important processes are taking place.
The materials upon which a tree feeds are derived from the soil and the air. The roots of a tree absorb water from the soil and with it the necessary nutrition and elements of the soil. The amount of water taken up by the roots is usually much larger than is required in the chemical processes which go on in the leaves. The tree gives away this unused water by a process known as transpiration. Great quantities of water vapor tend to keep the air in the forests humid and favorable to growth.
In the lives the food necessary for the trees’ growth is manufactured. The raw food materials which reach the tree through the roots and the leaves are digested in the leaves. They are then sent to all living parts of the roots, stem and crown where they are either used at once or stored away for later use.
Like all other plants and like animals trees breathe. The breathing is done through the leaves and the bark. Respiration is the factor supplying the energy with the aid of the green matter in the leaves. The energy is supplied by sunlight; the plant takes up carbon dioxide gas of which there is always a small amount in the atmosphere. The carbon is used to elaborate the organic compounds. The carbon assimilation is a most important biochemical process. The air would deteriorate rapidly if plants did not take up carbon dioxide and give off oxygen.
The earlier structure of wood is known as heartwood the outer, later sections as sapwood. The difference is in the moisture content and aging. Heartwood is found in all species of coniferous trees such as pine, fir, spruce, larch and in certain deciduous trees, for example, in oak, ash, elm, poplar, as well as in tropical trees.
Dead or heartwood trees no longer perform a function in the living tree. Hence, if the tree is injured by fire, the heartwood trees are in greater danger; the sapwood trees have greater resistance to fungus attack owing to their nature and content. On the other hand, when a tree has been cut and the timber seasoned the heartwood trees are more resistant to fungi and insect pests. The pores through which a leaf breathes are surrounded with tiny cells which serve to open and close the pores as the weather changes and as moisture and life vary. Trees grow from the top and in diameter; the side growth is also called secondary growth. Wood has layers of growth which appear as circles around the center. They are actually elongated cells and cluster of tubes. This makes it possible to split the wood vertically and prevent splitting across the grain. Wood varies in weight and in specific gravity. Some wood is heavier than water as, for example, the black iron in Florida, which will sink in water. With a few exceptions dry wood is lighter than water, but the moisture content of wood greatly affects its weight.
TEXT 13 CADASTRE
Nowadays great attention is paid to the rational use of earth resources. It is on the basis of cadastre that their value is determined. The earth itself is one of the main sources of natural resources. It needs to be protected. This is a function of cadastre.
What is cadastre? The derivation of the word “cadastre” used to be ascribed to the Latin “capitastrum” (contraction of “capitum registrum”), a register of “capita”, literally “heads” and so by extension “taxable land units”.
In continental Europe the word “cadastre” came to mean … a systematic classification and valuation of land, under the control of central government, by means of maps of parcels drafted on the basis of topographic surveys and recorded according to parcels in a register.
Cadastre is a systematized data bank of different projects, as concerns their legal and economic status, natural surroundings as well as their location. This bank is regularly renewed due to the constant control over the project.
Its appearance was caused by private land ownership and the necessity of collecting taxes from land owners. First it was a register including the list of taxable lands, with the area of each lot, its plan, soil type and the amount of tax being mentioned.
Now the cadastre is a methodically arranged public inventory of data on the properties within a certain country or district based on a survey of their boundaries. The outlines of the property are shown on large – scale maps.
Closely connected to the word “cadastre” is the term “cadastral survey”, which is simply defined as a survey of boundaries of land units. A cadastral survey may be carried out both for initial information of the parcel as well as for any subsequent changes of the boundaries of the parcel. A cadastral survey may also be conducted in order to re-establish the boundaries missing on the ground.
The concept “cadastre” includes the function of serving the purpose of land taxation and the function of providing a description of land units as a basis for registration of right and encumbrances on land. But a cadastre does not itself serve as a register of right and encumbrances.
Cadastral works embrace: land surveys in cities, towns and suburbs for registering and evaluation as well as for constructing engineering works, communications, industrial and civil structures and laying out lands for landowners. Depending on its object cadastre may be classed into land cadastre, city cadastre, city cadastre and taxation one.
Land cadastre embraces all the data on the lands, their legal, economic and environmental status and location. It is to secure rational earth resources exploration. Land cadastre presents a combination of plans and maps as well as different documents on lands, which give all-round characteristics of these territories. All the collected information may be stored in the computer data base.