Tiếng anh chuyên ngành Thổ nhưỡngvà Môi trường đất NXB Đại học quốc gia Hà Nội 2007. Tr 92 – 100. Tài liệu trong Thư viện điện tử ĐH Khoa học Tự nhiên có thể được sử dụng cho mục đích học tập và nghiên cứu cá nhân. Nghiêm cấm mọi hình thức sao chép, in ấn phục vụ các mục đích khác nếu không được sự chấp thuận của nhà xuất bản và tác giả. Mục lục Unit 10 Soil texture, porosity, acidity 2 A. Reading 2 I. Comprehension questions 3 II. True-false questions 4 III. Increasing your vocabulary 4 B. Writing 5 C. Further practice 6 D. Translation 8 I. Translate into Vietnamese 8 II. Translate into English 8 E. Vocabulary 9 Unit 10. Soil texture, porosity, acidity Nguyễn Thị Minh Nguyệt Unit 10 Soil texture, porosity, acidity A. Reading • Warm-up activities - Name the soils and their characteristics that you know. - Which soil is best for growing most crops? Soils vary in their content of clay (very fine particles), silt (fine particles), sand (medium-size particles), and gravel (coarse to very coarse particles). The relative amounts of the different sizes and types of mineral particles determine soil texture. Soils containing a mixture of clay, sand silt and humus are called loams. To get an idea of a soil's texture, take a small amount of topsoil, moisten it, and rub it between your fingers and thumb. A gritty feel means that it contains a lot of sand. A sticky feel means a high clay content, and you should be able to roll it into a clump. Silt-laden soil feels smooth like flour. A loam topsoil, best suited for plant growth, has a texture between these extremes-a crumbly, spongy feeling with many of its particles clumped loosely together. Soil texture helps determine soil porosity: a measure of the volume of pores or spaces per volume of soil and average distances between those spaces. A porous soil (with many pores) can hold water and air than a less porous soil. The average size of the spaces or pores in a soil determines soil permeability: the rate at which water and air move from upper to lower soil layers. Soil porosity is also influenced by soil structure: how soil particles are organized and clumped together. Loams are the best soils for growing most crops because they hold lots of water but not too tightly for plant roots to absorb. Sandy soils are easy to work, but water flows rapidly through them. They are useful for growing irrigated crops or those with low water requirements, such as peanuts and strawberries. The particles in clay soils are very small and easily compacted. When these soils get wet, they form large, dense clumps, explaining why wet clay can be molded into bricks and pottery. Clay soils are more porous and have a greater water-holding capacity than sandy soils, but the pore spaces are so small that these soils have a low permeability. Because little water can infiltrate to lower levels, the upper layers can easily become too waterlogged for most crops. Acidity and basicity of substances in water solution are commonly expressed in terms of pH. Soils vary in acidity, and the pH of a soil influences uptake of soil nutrients by plants. Plants vary in the pH ranges they can tolerate (Taken from "Sustaining the Earth" by Tyler Miller, G.) I. Comprehension questions Answer the following questions 1. How do soils vary? How can we give a concept of soil's texture? 2. Which soils are loams ? Why are they the best for growing crops? 3. Why can we roll soil with a high clay content? 4. Why does a porous soil hold more water and air than a less porous soil? 5. What does soil permeability mean? What can determine it? 6. Why can people mould wet clay into bricks and pottery? 7. What are characteristics of the particles in clay soil? 8. Are sandy soils useful for growing peanuts and strawberries? 9. What does the soil structure have influence on? 10. Why are the upper layers easy to become waterlogged for crops? II. True-false questions Decide whether the following statements are true "T" or false "F". Correct the false statements. 1. The relative amounts of the different sizes and types of mineral particles determine loams. 2. People have to depend on clay, silt, gravel and sand content to group soil into textual classes. 3. Loams are soils, which contain a mixture of clay, sand, silt, and humus. 4. It's difficult to get an idea of soil composition. 5. A less porous soil can hold less water than a porous soil. 6. There are not many pores in porous soil. 7. Sandy soil is good for growing peanuts and strawberries. 8. Bricks and pottery are made from wet clay. 9. Clay soils and sandy soils have the same water-holding capacity. 10. The pore spaces of clay soils are very small. III. Increasing your vocabulary Complete the following statements with the appreciate words given below: sand water and air mineral particles gravel wet clay sandy soil loams clay content soil texture 11. Soils containing a mixture of a clay, sand silt and humus are called (1) 12. Bricks and pottery are made from (2) 13. A porous soil (with many pores) can hold (3) than a less porous soil. 14. (4) are easy to work, but water flows rapidly through them. 15. A gritty feel means that it contains a lot of (5) 16. A sticky feel means a high (6) 17. The relative amounts of the different size and of (7) determine (8) 18. Soils vary in their content of clay, silt, sand and (9) B. Writing Sentence-transforming Finish each of the following sentences in such a way that it means the same as the sentence printed before it. 1. Soil containing a mixture of clay, sand, silt and humus are called loams. Loams are soils which 2. A porous soil can hold more water and air than a less porous soil. A less porous soil 3. Loams are the best soils for growing most crops because they hold lots of water but not too tightly for plant roots to absorb. As 4. It is useful for growing irrigated crops in sandy soils. Sandy soils 5. People can mold wet clay into bricks and pottery. Brick and pottery 6. Clay soils have a greater water-holding capacity than sandy soils. Sandy soils C. Further practice Exercise 1: Expression of degree Look at the following pairs of sentences. Notice that the first half of each sentence describes a state and the second half expresses a consequence. Example: The soil was dry so the seed could not germinate. The soil was heavy and clayey and , as a result, it was unsuitable for root crops We can express these sentences in another way using the expression of degree too: Example: The soil was too dry for the seed to germinate. The soil was too heavy and clayey to be suitable for root crops. Rewrite the following sentences using too as in example (c) and (d) above and make any other changes that are necessary. 7. The soil particles are fine so the water cannot percolate easily through the soil. 8. Because the soil was compact, it was not suitable for root crops. 9. Soil aeration was inadequate and consequently the plant could not receive a proper supply of oxygen. 10. As a result of the land being waterlogged, it was not possible to produce a healthy crop. 11. The soil profile was so shallow that it could not give the roots sufficient anchorage. 12. As the root system was poorly developed, the plant could not produce a good top growth. 13. It was dark as a result photosynthesis could not take place. 14. The current was so swift that the silt would not be deposited. Now look at the sentences you have written and rewrite them using not + adjective + enough, using the adjective given for each sentence . Example: The soil was too dry for the seed to germinate. (wet) = The soil was not wet enough for the seed to germinate. The soil was too heavy and clayey to be suitable for root crops. (light and sandy) = The soil was not light and sandy enough to be suitable for root crops. 1. The soil particles are fine so the water cannot percolate easily through the soil (coarse). 2. Because the soil was compact, it was not suitable for root crops. (loose) 3. Soil aeration was inadequate and consequently the plant could not receive a proper supply of oxygen. (adaquate) 4. As a result of the land being waterlogged, it was not possible to produce a healthy crop. (well-drained) 5. The soil profile was so shallow that it could not give the roots sufficient anchorage. (deep) 6. As the root system was poorly developed, the plant could not produce a good top growth. (well-developed) 7. It was dark as a result photosynthesis could not take place. (bright) 8. The current was so swift that the silt would not be deposited. (slow) D. Translation I. Translate into Vietnamese The soil is always an important component in the system comprising the lithosphere, the atmosphere and the biosphere. Soil particles reflect the varying nature of the interactions with this system. Soil is very essential for many human activities, and we can only successfully and sustainably undertake these activities if we understand how soil has been developed and how it is affected by changes in the system, particularly those in the biosphere caused by our manipulation of vegetation and soil. (Taken from "Environmental Sciences" by Wilson, R.) II. Translate into English 1. ánh sáng mặt trời cung cấp năng lượng cho quá trình chuyển nước từ đất và cacbon điôxít từ không khí thành đường và hyđrát cacbon. 2. Việc canh tác quá nhiều làm phá hủy cấu trúc của đất. 3. Nếu đất quá lạnh thì sự nảy mầm của cây cối không thể xảy ra. 4. Thành phần cơ giới là đặc tính quan trọng của đất bởi vì ở một phạm vi nào đó nó sẽ quyết định tỷ lệ hút nước, sự tích trữ nước ở trong đất, tính thấm khí và nó sẽ ảnh hưởng đến độ phì nhiêu của đất. Ví dụ, đất cát thô rất dễ canh tác, có tính thấm khí tốt cho sự phát triển của rễ và dễ làm ướt, nhưng loại đất này cũng khô rất nhanh và dễ bị mất các chất dinh dưỡng cho cây trồng. Còn các loại đất sét lại rất khó làm ướt, khó canh tác và cũng khó tháo rút nước. E. Vocabulary 1. absorb (v) : hấp thụ, ngấm 2. brick (n) : gạch 3. clay (n) : đất sét 4. clump (v) : tạo thành lùm, thành đống 5. coarse (adj) : thô, không mịn 6. compact (adj) : nén, rắn chắc 7. content (n) : hàm lượng 8. dense (adj) : dày đặc, chặt 9. grit (n) : hạt cát, hạt sỏi 10. infiltrate (v) : xâm nhập 11. irrigate (v) : tưới nước 12. loam (n) : đất giàu mùn, đất thịt 13. moisten (v) : làm ẩm 14. mold (v) : đúc theo khuôn 15. permeable (adj) : dễ them 16. porous (adj) : lỗ rỗng, tính rỗng 17. pottery (n) : đồ gốm 18. roll (v) : cuộn tròn, vo viên 19. rub (v) : chà xát 20. sticky (adj) : dẻo, dính 21. spongy (adj) : mềm, xốp, đàn hồi 22. tolerate (v) : chịu đựng 23. volume (n) : khối lượng 24. waterlogged (adj) : ngập úng . Tiếng anh chuyên ngành Thổ nhưỡngvà Môi trường đất NXB Đại học quốc gia Hà Nội 2007. Tr 92 – 100 . Tài liệu trong Thư viện điện tử ĐH Khoa. hưởng đến độ phì nhiêu của đất. Ví dụ, đất cát thô rất dễ canh tác, có tính thấm khí tốt cho sự phát triển của rễ và dễ làm ướt, nhưng loại đất này cũng khô rất nhanh và dễ bị mất các chất dinh. cho quá trình chuyển nước từ đất và cacbon điôxít từ không khí thành đường và hyđrát cacbon. 2. Việc canh tác quá nhiều làm phá hủy cấu trúc của đất. 3. Nếu đất quá lạnh thì sự nảy mầm