Hard chapters I need to study

13. Some soil colloids exhibit positive charges under highly acid conditions. To what are these charges likely due? A. protonation of some hydroxy groups by excess H" ions B. the adsorption of A13' ions on the colloid C. the release of some OH' ions leaving an unsatisfied positive charge on the colloid D. substitution of lower valent atoms for higher valent atoms in the octahedral sheet E. increase in the level of H* ions on the exchange complex

A

3. If you were seeking a soil colloid with a high capacity to adsorb cationic pollutants, but also with a consistent capacity to do so even as the pH varied form 4.0 to 7.5, which of the following would you choose? A. montmorillonite B. kaolinite C. fine-grained mica D. humus E. chlorite

A

8. The negative charges associated with smectite clay crystals are due mostly to: A. isomorphous substitution of Mg for Al in the octahedral sheet B. substitution of Al for Mg in the tetrahedral sheet C. high pH associated with the formation of the mineral D. substitution of Si for Al in the tetrahedral sheet E. OH groups on the external surface of the crystal

A

12. As biotite weathers in soils, which of the following would not likely develop by mere alteration of this mineral? A. fine-grained mica B. kaolinite C. smectite D.chlorite E. vermiculite

B

2. The electronegative charge on 2:1 type silicate clays is due primarily to A. ionization of surface OH groups B. substitution of one metallic atom for another in the crystal structure of the clay C. extremely small size of the individual colloid particles D. the effect of pH on the presence of 1-1* ions in the exchange complex E. the preponderance of tetrahedral sheets compared to octahedral sheets

B

9. The swelling/shrinking tendency of some silicate clay minerals is due primarily to the presence of: A. cations attracted by the negative charges on the internal surfaces B. the movement of water molecules in and out of the interlayers of the crystal C. varying thickness of the film of water covering the external surface of the particles D. expansion in the width of the interlayers due to movement of larger ions such as K, E. the high Mgt' contents in the octahedral layers

B

1. A soil pedon is A. a category of Soil Taxonomy B. a three-dimensional unit that embodies the primary characteristics of an individual soil C. generally larger in area than a polypedon D. a diagnostic subsurface horizon prominent in arid regions and in sandy parent materials. E. a surface horizon used to characterize soil suborders and great groups

B. a three-dimensional unit that embodies the primary characteristics of an individual soil

14. A 1 kg soil sample has 2 cmolc of A13' on the exchange complex. Addition of which of the following would most effectively replace about half of this Al? A. 1 cmol, K' B. 10 cmol OH C. 4 cmol Cat' D. 4 cmol, Na. E. 2 cmoL Na'

C

18. Allophane differs from other silicate clays in all ways but one of the following (select the one). A. nature of parent materials from which it forms B. degree of crystallization of the particles C. the presence of negative charges on the colloidal particles D. widespread occurrence around the world E. the period of time it has been subject to weathering

C

20. You find that the CEC of a sandy loam soil at pH 5.0 is 8 cmoldkg and at pH 8.2 it is 14 What is the most likely reason for this difference? A. increase in the pH-dependent charges on 1:1 type silicate clays B, removal of A13. ions from the exchange complex at higher pH. C. ionization of carboxyl and phenolic groups to release H. ions D. Removal of Al atoms from tetrahedral layers at low p1-1. E. replacement of trivalent Al3+ ions with divalent Cat' ions at high pH.

C

5. Which cation would you expect to be mostly tightly held in a soil at pH 4.5? A. K. B. Cat' C. A13* D. Mgt' E. Na*

C

23. Soil scientists generally map the soils in a landscape by sampling the soil in A. pre-determined a grid-like geometric pattern of evenly spaced points B. a computer-calculated pattern of random points C. auger holes made mostly near expected soil boundaries D. four soil pits, one dug in each corner of the area to be mapped E. A and D

C. auger holes made mostly near expected soil boundaries

11. A well drained soil under a rain forest in Brazil contains significant amounts of a silicate clay. Which of the following is it most apt to be? A. chlorite B. fine-grained mica C. smectite D. kaolinite E. vermiculite

D

17. Humus is an important soil colloid. It differs from 2:1 type minerals in all but one of the following characteristics (select the one). A. structural framework of the particles B. CEC dependence on soil pH C. influence of isomorphous substitution capable of adsorbing cations D. influence on soil aggregate stability

D

19. Which of the silicate clays would likely have the highest level of potassium in the crystal structure? A. kaolinite B. chlorite C. smectite D. fine-grained mica E. vermiculite

D

9. The nomenclature of Soil Taxonomy is characterized by all but which one of the following statements? A. Soil names (except for series level) identifies major soil characteristics. B. The names of the orders all end with the letters sols. C. The subgroup name also tells you the great group, suborder, and order names. D. The names give a clear indication of the modes of genesis of the soil. E. The names are based on measurable properties and not on presumed modes of genesis.

D. The names give a clear indication of the modes of genesis of the soil.

1. Which of the following is not a characteristic of soil colloids? A. very small size B. high external surfaces C. electronegative charges D. ability to exchange ions with the soil solution E. low water holding capacity

E

10. Which of the following silicate clays would be least apt to be formed from the mere alteration of primary minerals? A. smectite B. vermiculite C. chlorite D. fine-grained mica E. iron or aluminum oxides

E

15. An alkaline soil contains 20% clay and 3% humus. If the pure clay has a CEC of 40 cmol/kg and the humus 200 cmol/kg, calculate the CEC/kg of the soil. A.8 B.30 C.12 D.16 E.14

E

16. Anion exchange by formation of outer sphere complexes is of least importance in the plant absorption of A. NO3 B. Cl' C. SO42" D. Mo04'2 E. H2PO4'.

E

4. Soils rich in which type of clay would provide the most troublesome site on which to build a home? A. Fe, Al oxides B. kaolinite C. fine-grained micas D. chlorite E. smectite

E

22. While 2:1 type clays have significant internal surfaces, their external surfaces are generally much more extensive.

FALSE

23. Vermiculite and associated silicate clays have a net electropositive charge in slightly acid soils.

FALSE

25. Kaolinite is most prevalent in soils developed from volcanic ejecta (Andisols).

FALSE

26. The order of strength of adsorption of ions by most colloids when they are present in equivalentquantities is AI>Ca>K>Mg>Na.

FALSE

28. A tetrahedral sheet is characterized by a plane of aluminum atoms surrounded by oxygen and hydroxyl groups.

FALSE

30. Isomorphous substitution involves the substitution of a tetrahedral sheet for an octahedral sheet.

FALSE

31. The primary source of charge for 2:1 type clay minerals is ionization of the surface hydroxyl groups on the tetrahedral sheets.

FALSE

33. Humus has a much higher cation adsorption capacity at pH 5.5 than at pH 8.0.

FALSE

34. Of the silicate clays, smectite has the least tendency to expand upon wetting and shrink upon drying.

FALSE

35. Smectite and vermiculite are more prominent in extremely weathered soils than in soils where only modest weathering has occurred.

FALSE

37. The high cation adsorption capacity of vermiculite is due primarily to the substitution of silicon atoms for aluminum in the tetrahedral sheet.

FALSE

21. Soil colloids are too small to be seen with an ordinary light microscope.

TRUE

24. Iron and aluminum hydrous oxides are characteristic of soils that are highly weathered chemically.

TRUE

27. The leaf-like structure of silicate clays involves two kinds of horizontal sheets, one dominated by a plane of silicon atoms, the other by a plane of aluminum and/or magnesium.

TRUE

29. A 2:1 type silicate clay has one octahedral sheet sandwiched between two tetrahedral sheets.

TRUE

32. While kaolinite particles are larger than those of other major silicate clays, the surface area of kaolinite per kilogram is much smaller than that of the 2:1 type minerals.

TRUE

36. in most soils of the arid regions of Nevada, smectite is more prominent than in most soils in warm, humid Georgia.

TRUE

38. Even at pH values near 7.0 some colloids such as iron and aluminum oxides have negative surface charges less than 10 cmoljkg.

TRUE

39. The cation exchange capacity of a soil is determined primarily by the amount and kind of colloids in the soil and by the pH.

TRUE

40. You would expect the cation exchange capacities of Ultisols to be lower than those of Aridisols if the soil textures are about the same.

TRUE

6. If you were looking for a soil with high cation exchange capacity and were not concerned with the soil's physical properties, which of the following would most likely fit your needs? A. Aridisol B. Oxisol C. Vertisol D. Mollisol E. Ultisol

Vertisol

13. Argillic horizons are characterized by . A. accumulation of silicate clays B. high level of Na+ ions C. high levels of iron and aluminum oxides D. impervious hardpan layers E. organic matter accumulation

accumulation of silicate clays

6. Which of the following diagnostic horizons would likely not restrict root growth in soils? A. albic B. fragipan C. salic D. placic E. petrocalcic

albic

16. Which of the following describes a soil likely to contain a significant content of low activity clays? A. an Alfisol in New York B. a Mollisols in Central Brazil C. an Oxisol in Minnesota D. an Ultisol in the Congo River basin in Africa E. an Inceptisol in Mississippi

an Ultisol in the Congo River basin in Africa

4. Which soil moisture regime has the highest soil moisture levels? A. udic B. ustic C. aquic D. aridic E. xeric

aquic

21. In soils of which great group would you most likely find wide surface cracks during periods of dry weather? A. Calciusterts B. Albaqualfs C. Argiaquolls D. Kandiaquults E. Haplustox

calciusterts

14. Soils in which of the following suborders would be more likely to occur in Minnesota than in Texas? A. Fluvents B. Cryolls C. Udalfs D. Usterts E. Cambids

cryolls

11. In which soil orders would recent alluvium most likely be a common parent material? A. Ultisols B. Entisols C. Andisols D. Alfisols E. Aridisols

entisols

25. Epipedons are diagnostic subsoil horizons that are one of the primary means of classifying soils in the United States.

false

28. A pedon is a 3 dimensional field unit occupying about 1000 square meters (1 hectare) of land area.

false

31. For agricultural use in a given region, a soil with an ochric epipedon could generally be expected to be more productive than one with a mollic epipedon.

false

35. The categories of Soil Taxonomy can be listed from the broadest (first) and most specific (last) as: order, suborder, great group, subgroup, series, family.

false

37. Soils classified as Inceptisols have the least well developed profiles of those in any order in the Soil Taxonomy system.

false

41. Because soil development is just beginning in Entisols, these soils are generally less variable in properties than are those in the Andisol or Ultisol orders.

false

43. Spodosols are generally less acidic and less sandy than are Alfisols.

false

17. Which of the categories in the Soil Taxonomy system indicates properties that have implications for root growth as well as for the construction of building foundations? A. suborder B. family C. series D. great group E. subgroup

family

7. You are working with a soil colloid known to have a reasonably high potassium level, a cation exchange capacity of about 20 cmoljkg of clay and little tendency to swell when wetted. Which of the following is it most apt to be the dominant clay mineral in this soil? A. vermiculite B. smectite C. kaolinite D. humus E. fine-grained mica

fine grained mica

38. Soils in the Oxisols order are deeply weathered and have deep subsurface horizons of silicon oxide.

flase

22. Investigating the soils of northern Canada on summer, you dig a soil pit easily though fairly uniform peat material until, at 75 cm deep, your shovel hits a layer that is frozen solid. Into which type of soil are you most likely digging? A. Histosol B. Cryent C. Fibrist D. Histel E. Cryert

histel

19. If the soils are to be used for crop production, for which soil order would land drainage be most critical A. Mollisols B. Inceptisols C. Aridisols D. Oxisols E. Histosols

histosols

7. Which of the following soil temperature regimes would provide the warmest and least variable soil temperatures? A. Thermic B. Mesic C. Isomeric D. lsohyperthermic E. Hyperthermic

isohyperthermic

3. In which of the following epipedons is the organic matter level generally lowest? A. mollic B. umbric C. histic D. ochric E. melanic

ochric

5. Which of the following subsurface diagnostic horizons would you expect to find in a highly weathered soil of the humid tropics? A. cambic B. oxic C. natric D. salic E. spodic

oxic

2. Soil scientists from which country first conceived the idea that soils were natural bodies? A. United States B. France C. Russia D. Great Britain E. Belgium

russia

20. The map units on a detailed soil map on Web Soil Survey are most likely to be labeled with names from which category of Soil Taxonomy? A. order B. suborder C. great group D. subgroup E. series

series

8. Which of the following categories of Soil Taxonomy provides the greatest specificity of soil properties? A. series B. suborder C. order D. family E. great group

series

12. Soils in this order are commonly sandy in texture, quite acidic and develop primarily under coniferous trees in cool to cold climates A. Mollisols B. Andisols C. Spodosols D. Alfisols E. Ultisols

spodosols

24. Russian scientists were the first to develop the concept of soils as natural bodies.

true

26. Organic matter distribution in the profile is a significant criterion for differentiating epipedons.

true

27. The soil and a soil are two extremes in the concept of soils that is basic to most classification schemes.

true

29. A polypedon or individual soil is a group of closely related pedons that conceptually approximates what in the United States is called a soil series.

true

30. The two most significant characteristics of the classification system used in the United States are a unique system of terminology and focus on measurable soil properties as a primary basis for the classification.

true

32. An argillic horizon is a diagnostic horizon characterized by the subsurface accumulation of silicate clays.

true

33. An aquic soil moisture regime connotes a higher degree of soil moisture saturation than an ustic one.

true

34. The broadest category of classification in Soil Taxonomy specifies 12 soil orders, 11 of which are for mineral soils.

true

36. The name of a subgroup indicates the order, suborder, and great group of which it is a member.

true

39. Andisols are found mostly near recently active volcanoes.

true

40. Mollisols are characterized by a deep epipedon that is high in organic matter.

true

42. Vertisols are characterized by high contents of swelling-type silicate clays.

true

44. The family category focuses on properties affecting plant roots and suitability for engineering uses of soils.

true

45. You would be more apt to find an Gelisol in Alaska than in Iowa.

true

46. Oxisols are more highly weathered than are the soils of any other order.

true

47. Histosols generally have higher organic matter contents than Mollisols.

true

18. Soils in which of the following soil suborders would most likely have a prominent E horizon under the A horizon? A. Ustox B. Udalfs C. Orthents D. Aquepts E. Udolls

udalfs

10. A soil has a thick black A horizon, a distinct B horizon, has reasonably stable soil structure, and was formed under grassland natural vegetation. In which suborder is it most likely classed? A. udolls B. ustalfs C. cambids D. aquents E. udults.

udolls

15. You are seeking a soil with high clay content but one that is not sticky when wet nor hard and cloddy when dry. In which of the following suborders would you most likely find this soil? A. Udert B. Ustalfs C. Aquands D. Ustox E. Cambids

ustox