Павлова Н.Ю. УП_АЯ_Ч1

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3.Give questions to these answers:

1.No factor is more critical for sustaining civilization than maintaining soil and water resources.

2.Soil degradation is happening because of poor management.

3.Soil system is the dynamic interaction of minerals, detritus, and soil organisms.

4.The proportion of sand, silt and clay making up the mineral portion of any soil is defined as soil texture.

5.Yes, it does. Soil texture has a significant effect on infiltration, aeration, waterholding capacity, and nutrient-holding capacity.

6.Total surface area increases with diminishing particle size.

7.Soil texture also affects workability, the ease with which a soil can be cultivated.

8.Yes, they are. Clayey soils are very difficult to work because with even modest changes in moisture content they go from being too sticky and muddy to being too hard to break.

9.Sandy soils are very easy to work because they do not become muddy when wet, nor do they become bricklike when dry.

10.The best texture proves to be silt or loam.

4.Answer the questions:

1.Why is degradation of soils happening throughout the world?

2.What is the soil system?

3.What is happening as a result of weathering?

4.What do you know about soil texture?

5.What types of soil do you know?

6.How does holding capacity increase?

7.What does soil texture also affect?

8.What types of soil are easy to work and which are very difficult?

9.Which types of soil have the best texture?

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5. Multiple choice

Plants and Soil

Soil 1… far 2… than just 3… dirt. Soil is a dynamic 4… involving three components: mineral 5…, detritus, and soil 6… feeding on the detritus. This three-

7… soil system is 8… 9… successful completion of nutrient 10… ; remove 11…

component and soil 12… becomes compromised. In addition 13… providing 14… ,

the soil system also 15… as an environment that supports plant 16… in other respects. Hence, maintenance 17… this soil system is critical to the 18… of the ecosystem as a whole. To understand the importance of 19… aspects of the soil system it is necessary to consider the needs of the growing 20… as they relate to the

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6. Render in English:

Нет фактора более решающего для выживания цивилизации, чем сохранение почвенных и водных ресурсов. Ряд прошлых цивилизаций погибли,

т.к. не учли это. И современные цивилизации, кажется, не поняли этого, т.к. во всем мире почвы ухудшаются, а использование водных ресурсов увеличивается, угрожая будущей продуктивности сельского хозяйства, лесов и пастбищ.

Хорошо известно, что почвенная система – это динамичное взаимодействие минералов, детритов и почвенных организмов. В результате выветривания, твердая порода постепенно разрушается на мелкие частицы,

которые классифицируются по размеру от больших до микроскопических,

таких как песок, ил и глина. Соотношение песка, ила и глины, образующих минеральный состав любой почвы, называется строение почвы. Почвы бывают чисто песчаными, чисто пылеватыми, или чисто глинистыми. Соотношение,

которое можно обычно обнаружить, состоит из приблизительно 40% ила и 20%

глины. Почва с таким соотношением называется суглинком.

Строение почвы оказывает значительное воздействие на инфильтрацию,

аэрацию, водоудерживающую способность почвы по двум причинам. Во-

первых, более крупный размер частиц означает большее пространство между частицами. Следовательно, инфильтрация и аэрация улучшаются с увеличением размера частиц и ухудшаются при их уменьшении. Поэтому, в

песчаных почвах инфильтрация и аэрация прекрасные, а в глинистых почвах -

плохие. Пылеватые почвы являются средними.

Во-вторых, удерживающая способность обратно пропорциональна размеру частиц. Она очень плохая в песчаных почвах и улучшается с уменьшением размера частиц, так как и вода, и питательные вещества удерживаются благодаря прилипанию к поверхности частиц. Чем больше поверхность, тем больше удерживающая способность.

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Строение почвы влияет также на пригодность почвы к обработке.

Глинистые почвы обрабатывать трудно, потому что они бывают слишком липкие и грязные, или слишком твердые. Песчаные почвы очень легки в обработке, потому что они не становятся грязными при увлажнении и затвердевают при высыхании.

7. Translate into English the summary of the text:

В тексте говорится, что сохранение почвенных и водных ресурсов является решающим фактором для выживания современной цивилизации.

Подчеркивается, что почвенная система – это динамичное взаимодействие минералов, детритов и почвенных организмов. Соотношение песка, ила и глины в минеральном составе почвы называется строением почвы. Строение почвы оказывает существенное влияние на инфильтрацию, аэрацию и еѐ водоудерживающую способность. Строение почвы влияет также на пригодность почвы к обработке.

Additional Texts

Mineral Nutrients and Nutrient-Holding Capacity

Soil fertility, the soil’s ability to support plant growth often refers specifically to the presence of proper amounts of nutrients.

Mineral nutrients – phosphate, potassium, calcium, and other ions – are present in various rocks along with nonnutrient elements. However, plants cannot absorb these nutrient ions as long as they are bonded in the rock structure. The rock must be broken down such that the nutrient ions are released into water solution or into a loosely bound state.

The rock, referred to as parent material, is naturally broken down by weathering. Weathering includes all the physical forces acting on the rock, such as freezing and thawing, heating and cooling, the abrasive action of sand particles, and pressure exerted by roots growing in small cracks in the rock. In addition, various

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chemical reactions that break down the rock into smaller particles are part of the weathering process.

As nutrient ions are released from rock, they may be absorbed by roots, but they may also be washed away by water percolating through the soil, a process called leaching. Leaching not only causes a loss of soil fertility but also contributes to pollution as excess nutrients enter waterways. Consequently the soil’s capacity to bind and hold nutrient ions until they are absorbed by roots is just as important as the initial supply of those ions. This property is referred to as either the soil’s nutrientholding capacity or its ion-exchange capacity.

Although weathering is the original source of nutrients, this process is much too slow to support anything approaching normal plant growth. Also, some soils may be essential nutrients. For natural ecosystems, the major supply of mineral nutrients in the soil comes from the nutrient cycles.

In agricultural systems, there is an unavoidable removal of nutrients from the soil because nutrients are contained in the plant material harvested. Consequently, sustainability of agricultural systems requires that the soil be resupplied with nutrients. This is done through applications of fertilizer, material that contains one or more of the necessary nutrients. Fertilizers are generally divided into organic and inorganic. Organic fertilizer includes plant or animal wastes or both; manure is one example. Inorganic fertilizers are chemical formulations of required nutrients without any organic matter included.

Even with the potential for fertilization, the nutrient-holding capacity of the soil remains vitally important. Without such capacity, added fertilizer will simply leach away, an obvious economic loss. Even worse, leached nutrients go into waterways and cause serious pollution problems.

Exercises

1. Match English words and word combinations with their Russian

equivalents:

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2.Фосфат, калий, кальций и другие ионы являются минеральными питательными веществами.

3.Выщелачивание вызывает потерю почвенного плодородия.

4.Способность почвы удерживать ионы питательных веществ является еѐ важным свойством.

5.Различные химические реакции являются частью процесса выветривания.

6.Выветривание является первоначальным источником питательных веществ.

7.Внесение удобрений повторно снабжает почву питательными веществами.

8.Удобрения обычно делятся на органические и неорганические.

Water and water-holding capacity

Plant leaves have tiny pores that permit the plant to absorb carbon dioxide and release oxygen in photosynthesis. These pores, however, also allow water vapor to escape from the cells inside the leaves. This loss of water vapor from leaves, called transpiration, accounts for at least 99 percent of a plant’s need for water; less than 1 percent of the water absorbed is used in photosynthesis. If there is inadequate water to replace transpiration loss, plants wilt. The wilted condition conserves water and may hold off total dehydration and death for some time, but it also shuts off absorption of carbon dioxide and growth. Consequently, to keep most plants flourishing requires considerable amounts of water. A field of corn, for example, transpires an equivalent of a layer of water 17 inches (43 cm) deep in a single growing season.

The initial supply of any water in the soil is from natural rainfall or irrigation, but three soil factors are critical in making this water available to plants. First, the soil must be porous so that water can infiltrate, or soak in. If rainfall or irrigation water runs off the surface rather than infiltrating, it won’t be useful; worse, it tends to cause erosion. Second is water-holding capacity, the ability of the soil to soak up and hold the water like a sponge. Since the roots of most plants do not go very deep, water that trickles down through the soil more than a few feet (much less in the case of small plants) becomes unavailable. Between rains, plants depend on the “reservoir” of

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water that is held in the soil near the surface. With good water-holding capacity, this reservoir may be sufficient to sustain plants over a considerable dry spell. With poor water-holding capacity, plants may suffer during even a short dry spell because the small reservoir is quickly exhausted. The third factor critical in making water available to plants is evaporation rate from the soil surface. Factors that reduce evaporation water loss, such as a layer of detritus (mulch) on the surface, make more water available to the plants.

Exercises

1. Match English words and word combinations with their Russian

2.Answer the questions:

1.What is called transpiration?

2.How much water is used in photosynthesis?

3.When do plants wilt?

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4.Where is the initial supply of any water in the soil from?

5.What are the three critical soil factors making water available to plants?

6.Will rainfall or irrigation water be useful if it runs off the surface rather than infiltrating?

7.Is water-holding capacity the ability of the soil to soak up and hold the water or to infiltrate it?

3.Translate into English:

1.Потеря водяного пара с листьев называется транспирацией.

2.В фотосинтезе используется меньше 1% поглощѐнной воды.

3.Чтобы большинство растений цвели, требуется значительное количество воды.

4.Например, кукурузное поле испаряет слой воды 17 дюймов (43 см) за один сезон роста.

5.Начальное поступление любой воды в почву происходит из естественных осадков или орошения.

6.Три почвенных фактора являются критическими, чтобы сделать эту воду доступной для растений.

7.Первый фактор – почва должна быть пористой.

8.Вторым фактором является водоудерживающая способность почвы.

9.Третьим фактором является скорость испарения с поверхности почвы.

Aeration and other critical factors

Aeration. While leaves or other green parts of plants exposed to light carry on photosynthesis, roots and other nonphotosynthesizing parts derive energy from cell respiration, a process that requires oxygen and produces carbon dioxide as a waste. In general, plants have no means of transporting the oxygen produced in photosynthesis to the roots. Instead, roots depend on oxygen diffusing from the atmosphere through the soil, a property referred to as soil aeration. Thus, soil must be loose and porous if there is to be adequate aeration. If soil aeration is reduced through compaction

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(packing soil down tightly) or flooding, plants will suffer. Indeed, a common pitfall is to kill plants by “drowning”, that is, overwatering to the extent that aeration is impeded and roots suffocate and die.

Plants that thrive in the waterlogged soils of wetlands have adaptations that enable oxygen to diffuse through the stem to the roots.

Relative acidity (pH). The term pH refers to the units and scale used to measure the acidity or alkalinity of any solution. A solution that is neither acidic nor alkaline is said to be neutral and has a pH of 7. Most plants (as well as animals) usually require a pH near neutral, and most natural environments provide this.

Salt and water uptake. To function properly, all living cells must contain a certain amount of water. Plant cells get their water through plant roots (except in the case of certain specialized plants, such as epiphytes, which may absorb water through their leaves). A buildup of salts in the soil makes it impossible for the roots to take in water. Indeed, if salt levels in the soil get high enough, water can be drawn out of the plant, resulting in dehydration and death. This is why highly salted soils are virtual deserts supporting no life at all.

Exercises

1. Match English words and word combinations with their Russian