Tiếng anh chuyên ngành Thổ nhưỡngvà Môi trường đất NXB Đại học quốc gia Hà Nội 2007. Tr 101 – 109. 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 11 The origin And composition of soil 2 A. Reading 2 I. Comprehension questions 3 II. True - False sentences 4 III. Increasing your vocabulary 5 B. Writing 5 I. Sentence-rephrasing 5 C. Further practice 7 D. Translation 8 I. Translate into Vietnamese 8 II. Translate into English 9 E. VOCABULARY 9 Unit 11. The origin And composition of soil Nguyễn Thị Minh Nguyệt Unit 11 The origin And composition of soil A. Reading a. Warm-up Activities - What does weathering mean? - Is chemical weathering different from physical one? Soil is the residue composed of two main ingredients: mineral material and organic material. 2 Organic material originates from dead plants and animals and materials other than this are derived from rocks of various kinds. These rocks are broken down into small particles by mechanical disintegration and chemical decomposition. This breaking process, known as weathering, may thus be both physical and chemical. 5 When weathering processes are largely physical-by heat or wind, for instance-the composition of the soil is very similar to that of parent rock. In arid regions weathering is mostly by physical means. But in humid regions chemical processes of weathering are equally important. 8 In such regions rock particles are affected by water which may contain carbonic or other weak acids. These acids dissolve some of the particles in the rocks. The mineral material that is left behind is insoluble. Consequently, the insoluble mineral residues in the soil have less resemblance to the original rocks. There are large amounts of organic matter in the so down il, too. The process of soil formation results in the development of the soil profile. 14 This is made up of a succession of horizontal layers, or "horizons", of varying thickness, from the surface to the parent rock. Generally speaking, there are three distinct horizons, known as A, B and C. A is the topsoil, which is coarse-grained, and dark in color because of the presence of humus. B is known as the sub-soil which contains some of the products leached, or washed, out of the A-horizon. The C-horizon consists of parent material which has been weathered in the upper part, and unweathered rock bellow. Any sample of soil contains particles of different sizes. 20 These have been divided into the following size groups: Material Diameter (mm) Gravel coarse sand fine sand silt clay more than 2.0 2.0-0.2 0.2-0.02 0.02-0.002 less than 0.002 Soils range from pure clays to pure sands. 22 Most of them contain various proportions of sand, silt, and clay and these varying proportion make up a soil 's textural class. The principle classes in order of increasing fineness of material are sand, loamy sand, loam, silt, silty clay loam, clay loam, silt and clay. Any soil contains both mineral and organic matter. 25 Clay particles are the most important of the mineral particles because they are the smallest. Smaller the sized particles have a greater exposed surface area than larger sized particles. The smaller the size of a particle, the greater is its reactivity. That is to say, smaller sized particles can react or combine with water, nutrients and humus more easily than larger sized particles. Thus, a clay soil is more reactive than any other type of soil. Humus from decomposed organic matter is vital to a soil as it makes a heavier soil lighter. 31 In addition, it helps to bind the mineral particles together in "crumbs". (Taken from "English in Agriculture" by Alan Mountford) I. Comprehension questions Answer the following questions 1. What are the two major ingredients of soil? 2. Where does organic material and inorganic material originate? 3. When is the composition of the soil and the parent rock the same? 4. What are the rock particles in humid regions affected by? What does water in such regions consist of? 5. What kind of material is insoluble when acids dissolve some particles in the rocks? 6. What lead to the development of the soil profile? 7. How many distinct horizons are there? What are they? What are the C-horizon composed of? 8. What is the color of the topsoil? How many groups can we divide particles of different sizes into? 9. Why are clay particles the most important of the mineral particles? 10. What is the importance of humus? II. True - False sentences Decide whether the following statements are true "T" or false "F". Correct the false sentences. 1. Mineral materials in soil are derived from various kinds of rocks. 2. Physical weathering doesn't break down rocks into particles, neither does chemical one. 3. The composition of the soil in arid regions has a close resemblance to that of the parent rock. 4. Soils in arid regions and soils in humid regions are the same. 5. Soils in humid regions are similar to the parent rock. 6. There are a succession of soil horizons from the surface to the parent rock. 7. Particles bigger than silt are clay particles . 8. A clay loam contains particles of greater fineness than a loamy sand. 9. Gravel particles are the least important of the mineral particles because of being the biggest. 10. If the size of a particle is larger, its reactivity is better. III. Increasing your vocabulary Synonyms: Find words or phrase in the text which have the same meaning as: 1. areas 2. damp 3. incapable of being dissolved 4. cohere 5. original rocks 6. rot 7. rough 8. similarity 9. small stones 10. substance that provides essential nourishment B. Writing I. Sentence-rephrasing Rewrite the following sentences replacing the words printed in italics with expressions from the text which have the same meaning : 1. Material other than mineral material is derived from dead plants and animals. 2. Breaking down rocks into small particles is performed mostly by heat or wind in arid and semi-arid regions. 3. The remains of mineral materials that can not be dissolved in water have litter similarity to the parent rocks in humid regions. 4. The succession of horizontal layers in a soil are called the topsoil, the sub-soil and the parent material. Writing descriptions There are various patterns for describing the structure of the soil. Examples: The soil is a loam that is slightly compact in structure. = The soil is a loam with a slightly compact structure. = The soil is a loam with a structure that is slightly compact. = The soil is a loam that has a slightly compact structure. = The soil is a loam having a slightly compact structure. Rephrase he sentences below in each of the other ways shown in the examples above: 5. The soil is a sandy loam that is granular in structure. 6. The soil is a sandy loam with a cemented and compact structure. 7. The soil is a silty loam with a structure that is blocky and weakly granular. 8. The soil is a clay loam that has a laminated and compact structure. C. Further practice Exercise 1. Word-checking: Fill in each gap with a word or phrase without looking back the text: 1. If the soil material is not organic, it is derived from 2. Rocks of various kinds are into small particles. 3. 3. The breaking down process is known as 4. Weathering may be both and 5. If the weathering processes are physical the composition of the soil is very to the composition of the rock. 6. In humid regions the water dissolves some of the rock particles, but leaves behind mineral material that is 7. From the surface to the parent rock there are a succession of horizontal layers, or- 8. Sand, loamy sand, loam, silt loam, silty clay loam, clay loam, silt and clay are arranged in order of of particles. 9. Clay loam comes after sand. 10. A clay loam contains of greater fineness than loamy sand. Exercise 2. Contextual reference: 1. In sentence 2 this refers to: a. mineral material b. organic material 2. In sentence 5 that refers to: a. heat or wind b. the composition c. the soil 3. In sentence 8 such regions refers to: a. arid regions b. humid regions 4. In sentence 14 this refers to: a. the process of soil formation b. the development of the soil profile c. the soil profile itself 5. In sentence 20 these refers to: a. particles b. different sizes 6. In sentence 22 them refers to: a. soils b. pure clays c. pure sands 7. In sentence 25 they refers to: a. mineral particles b. clay particles 8. In sentence 31 it refers to: a. a heavy soil b. organic matter c. humus D. Translation I. Translate into Vietnamese There is much scientific work that remains to be done to improve our understanding of the biology of soil. The development of food production systems which exploit biological processes to a greater extent should now be the common aim of scientists in both developed and developing countries. However, the use of pesticides and inorganic fertilizers is likely to continue, combined with biological control agents, to form integrated systems of pest and disease control. Such strategies will involve a shift away from energy- intensive technologies to more knowledge-intensive technologies. (Taken from "English in Agriculture" by Alan Mountford) II. Translate into English 1. Hai thành phần chính của đất là chất hữu cơ và chất vô cơ. Chúng thay đổi cùng với thời gian. 2. Ngày nay vai trò của đất trong việc tác động đến cấu tạo của nguồn nước, đặc biệt liên quan đến chất lượng của nước uống, đang trở nên một vấn đề lớn trên thế giới. 3. Đất mà trong đó sét chiếm ưu thế gọi là đất sét. Đất mà có hàm lượng bùn cao gọi là đất bùn. Đất có tỷ lệ cát cao gọi là đất cát. Một loại đất mà không thể hiện những đặc tính vật lý nổi bật như ba nhóm trên gọi là đất thịt. Điều đáng lưu ý là đất thịt không chứa tỷ lệ phần trăm bằng nhau của cát, bùn và đất sét. Tuy nhiên, đất thịt lại thể hiện những đặc tính tương đối giống nhau của cát, bùn và sét. E. VOCABULARY 1. arid (adj) : khô 2. bind (v) : trói, buộc, kết hợp 3. blocky (adj) : khối, tảng 4. coarse (adj) : không mịn, thô 5. decompose (v) : phân huỷ 6. disintegrate (v) : làm tan rã 7. fineness (n) : độ mịn 8. gravel (n) : sỏi 9. horizon (n) : tầng (đất) 10. humid (adj) : ẩm ướt 11. humidify (v) : làm cho ẩm 12. insoluble (adj) : không thể thấm được 13. largely (adv) : ở một chừng mực nào đó 14. loam (n) : đất giàu mùn, đất thịt 15. nutrient (n) : dưỡng chất 16. originate (v) : bắt nguồn 17. parent rock (n) : đá gốc 18. resemblance (n) : sự giống nhau 19. resemble (v) : giống với 20. residue (n) : cặn 21. silt (n) : phù sa (limon) 22. subsoil (n) : lớp đất dưới 23. succession (n) : sự nối tiếp, chuỗi . độ mịn 8. gravel (n) : sỏi 9. horizon (n) : tầng ( ất) 10. humid (adj) : ẩm ướt 11. humidify (v) : làm cho ẩm 12. insoluble (adj) : không thể thấm được 13. largely (adv) : ở một chừng mực. arid (adj) : khô 2. bind (v) : trói, buộc, kết hợp 3. blocky (adj) : khối, tảng 4. coarse (adj) : không mịn, thô 5. decompose (v) : phân huỷ 6. disintegrate (v) : làm tan rã 7. fineness (n). 14. loam (n) : đất giàu mùn, đất thịt 15. nutrient (n) : dưỡng chất 16. originate (v) : bắt nguồn 17. parent rock (n) : đá gốc 18. resemblance (n) : sự giống nhau 19. resemble (v) : giống