Soil Practice Final

28. In acid soils, the principal chemical form of phosphorous available for plant uptake is__________. A: H2PO4 B: HPO4 C: P2O5

A: H2PO4

9. In which of the following epipedons is the organic matter level generally highest? A: Histic B: Mollic

A: Histic

67. Given the information in the table, calculate the base saturation of this soil? 10 cmol as Ca2+ 5 cmol as Mg2+ 2 cmol as K+ 1 cmol as Na+ 1 cmol as Al3+ 1 cmol as H+

90%

49. Given that you start with 40 g of soil, a 40 sec hydrometer reading is 20g and a 2 hr reading is 14g. What is the texture of this soil? (textural triangle is attached) A: Sandy Clay B: Loam C: Silty Clay Loam

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59. Given that you have 24 g of Mg2+, how many cmol are present?( M.W. of Mg2+=24 grams, 100 cmol) A) 200 B) 400 C) 4

A) 200

70. In what range of soil pH is phosphorus generally most available to plants? A) 5.5 to 7.0 B) 4.5 to 5.5 C) 3.5 to 4.5

A) 5.5 to 7.0

90. Which soil moisture regime has the lowest soil moisture levels? A) uridic B) uric C) aquic

A) Aridic

69. Clay, iron oxide, and aluminum oxide loss is most common in the A) E horizon B) B horizon c) O horizon

A) E horizon

80. Which of the following statements about soil erosion is not true? A) Less than 20 percent of the total soil erosion in the United states comes from croplands B) downstream off site costs of erosion are often higher than those in upstream fields from which the soil came C) The rate of soil erosion loss in the U.S. declined from 1980 to 1995

A) Less than 20 percent of the total soil erosion in the United states comes from croplands

60. Assume you want to grow azaleas in a soil with a pH of 6.0 , there application of which of the following would be most appropriate to decrease the soil pH? A) Elemental Sulfer B) Chicken Manure C) gypsum

A) elemental sulfur

75. You are working with a soil colloid known to have a reasonably high potassium level, a cation exchange capacity of about 20 cmol / kg of clay and little tendency to swell when wetted. Which of the following is most apt to be the dominant clay mineral in this soil? A) fine grained mica B) smectite C) kaolinite

A) fine grained mica

83. The great majority of nitrogen in soils can be found in the form of A) organic compounds B) dissolved cations C) dissolved anions

A) organic compounds

58. Which of the following statements is not correct? A) Tropical forests protect the soil from global warming B) The type of native vegetation is controlled primarily by climate C) Dense forests are found soil profiles have prominent O horizons

A) tropical forests protect the soil from excessive weathering

54. Which mineral is least resistant to weathering under humid temperate conditions? A) Gypsum B) Gibbsite C) Muscovite

A. Gypsum

72. Plants obtain nitrogen from the soil by taking up A) soluble cations B) soluble anions C) all of the above

A. Soluble cations

44. Other things being equal, a soil with 30% clay of the _____ type would be expected to have the greatest potassium- fixing capacity. A: 2:1 B: 1:1

A: 2:1

5. To be classified as a conservation tillage practice, a system must leave at least ______% of the soil surface covered with plant residues? A: 30% B: 50%

A: 30%

45. Humus is an important soil colloid which of the following is NOT true? A: Humus is not capable of absorbing cation B: Huus has influence on soil aggregates stability C: Humus is very important in isomorphous substitution

A: Humus is not capable of absorbing cation

35. The reaction: mica + H20 ----> K+ OH- + acid clay is an example of _________. A: Hydrolysis B: Hydration

A: Hydrolysis

3. A cover crop is usually grown for the purpose_________? A: Improving Soil Physical properties and saving/recycling nutrients

A: Improving Soil Physical properties and saving/recycling nutrients

17. Compared to an underlying silty clay B horizon, how much micropore space would there be as a percentage of total pore space in an overlying silt-loam A horizon A: Less B: Greater

A: Less

43. Soil A has a redox potential of 400 mV, soil B-200 mV. Of the two soils, Soil B is more apt to be characterized by an abundance of ________. A: Mn^2+ ions B: Fe^3+ ions C: molecular oxygen

A: Mn^2+ ions

25. To be practical, a nitrification inhibitor should kill or inhibit____________ A: Nitrobacter B: Nitrosomonas

A: Nitrobacter

7. Using the feel method, a soil creates a medium ribbon when pinched between the thumb and forefinger, the ribbon feels rough (like sandpaper). What is the most likely soil texture. A: Sandy Clay loam B: Clay

A: Sandy Clay loam

40. If a manager can afford only a limited amount of soluble P fertilizer for a calcareous soil with low phosphorus availability, the best plant growth is likely to be obtained if the P fertilizer is applied? A: in narrow braids or localized concentrations B: well in advance of the plant's main period of nutrient uptake

A: in narrow braids or localized concentrations

16. Applied to agricultural crops, the term lodging refers to? A: plants falling over, often as a result of too much N B: short, stubby plants starving for N or S

A: plants falling over, often as a result of too much N

46. Ammonium fixation would be expected to be greatest in soils containing a lot of __________. A: vermiculite B: Frankia C: Rhizobium bacteria

A: vermiculite

23. In the early stages of plant nitrogen deficiency, the most obvious symptoms are_____________ A: yellowish colors in the oldest leaves B: yellowing colors in the youngest leaves

A: yellowish colors in the oldest leaves

56. In acid soils, the principle chemical form of potassium available for plant uptake is A) K2O B) K+ C) HKO2

B) K+

82. The sites in certain clay minerals which fix potassium ions are also capable of fixing which other ion? A) Ca2+ B) NH4+ C) H+

B) NH4+

79. Because of soils developed in marine marshes can become extremely acidic if drained for agriculture or used as topsoil A) reduction of elemental sulfur B) Oxidation of sulfides C) reduction of sulfates

B) Oxidation of sulfides

64. Ammonia losses are likely to be greatest if a nitrogen source is placed about 10 cm deep in A) an acid sandy loam B) A calcareous sandy loam soil C) a calcareous clay loam soil

B) a calcareous sandy loam soil

74. Groundwater A) moves downward in the vadose zone through the capillary fringe. B) is a major source of water for irrigation in the United states C) is found mostly in shallow layers just below argillic

B) is a major source of water for irrigation in the United states

89. Buffer strips principally function in nutrient management to A) slow the movement of potential pollutants to the groundwater B) prevent the transport of nutrients from fields to streams C) enrich the soil with nutrients that are needed for optimum plant growth

B) prevent the transport of nutrients from fields to streams

68. Accelerated erosion is generally not affected by A) soil texture B) soil pH C) Soil moisture D) Soil crusting E) bulk density of soil

B) soil pH

81. The electronegative charge on 2:1 type silicate clays is due primarily to A) the effect of pH on the presence of H+ ions in the exchange complex B) substitution of one metallic atom for another in the crystal structure of the clay C) the preponderance of tetrahedral sheets compared to octahedral sheets.

B) substitution of one metallic atom for another in the crystal structure of the clay

50. Within the technical capabilities of the particular lab, most soil test results can be interpreted as indicating the ? A) Total amount of each nutrient in the soil B)Probability that nutrient application will improve plant growth C) amount or concentration of nutrient in the soil solution D) amount of nutrient present in plant available forms E) amount of nutrient needed to achieve balanced soil fertility

B)Probability that nutrient application will improve plant growth

53. An alkaline soil contains 40% clay and 1% humus. If the pure clay has a CEC of 40 cmol/kg, and the humus 200 cmol/kg, calculate the CEC of the soil A) 16 B) 18 C) 14

B. 18

55. Approximately what percentage of the P in surface soils is typically found in organic form? A) .1 to .5% B) 25 to 75% C) 1 to 5%

B. 25 to 75%

22. The partial pressure of oxygen in the atmosphere is .21 bar and that of nitrogen is .78 which of the following partial pressure levels would you expect to find in the pores of a moderately well drained soil? A: 0.30 (oxygen) B: 0.15 (oxygen)

B: 0.15 (oxygen)

15. Given a H+ ion concentration of 0.0000000063, what is the pH of the soil? A: 4.7 B: 7.2 C: 6.5

B: 7.2

26. Organic matter additions to a soil can decrease? A: Dp B: Db

B: Db

18. An excess of N typically____________ the maturity of annual plants? A: Delays B: Hastens

B: Hastens

8. In explaining erosion processes to a friend, which of the following would you say about accelerated erosion? A:It involves a much less rapid process than geological erosion B: It is greatly enhanced by the splash effect of raindrops impacting bare soil

B: It is greatly enhanced by the splash effect of raindrops impacting bare soil

1. Alluvial Fans are usually characterized by________? A: Nearly level B: Sandy Gravelly

B: Sandy Gravelly

12. The P factor in universal soil-loss equation is concerned with all but one of the following? A: Terraces B: Soil erodibility C: Contour tillage

B: Soil erodibility

24. The following are characteristics of a water molecule. A: The two H atoms are on diametrically opposite ends of the molecule B: The H to O to H is approximately 90 degree Celsius C: It has a positive and a negative side

B: The H to O to H is approximately 90 degree Celsius

29. Which of the following best characteristics the field capacity of a soil? A: Soil with water potential of -1500kPa B: Water content of a soil with water potential of about -10 kPa

B: Water content of a soil with water potential of about -10 kPa

4. The process of aerobic respiration is a significant source of which of the following gases? A: oxygen B: carbon dioxide

B: carbon dioxide

32. Aggregate dispersion can lead to soil: A: formation B: crusting

B: crusting

27. Decreasing the organic matter content of a soil is likely to_________ A: have no effect on water holding capacity B: decrease the soil's water holding capacity c: increase the soil's water holding capacity

B: decrease the soil's water holding capacity

39. 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: subgroup B: family

B: family

10. To monitor the effects of management on soil fertility, it is best to sample the soils in an area_______ A: Every one to three years B: from the same depth every time C: at the same season every time D: All of the Above

B: from the same depth every time

37. The opposite process from mineralization is ____________ A: denitrification B: immobilization

B: immobilization

47. In most soil, mineralization of soil organic matter is an important source of plant available __________. A: potassium B: phosphorus C: both a and b

B: phosphorus

33. Some soil colloids exhibit positive charges under highly acid conditions. To what are these charges likely due? A: increase in the level of H+ ions on the exchanging complex B: protonation of some hydroxy groups by excess H+ ions

B: protonation of some hydroxy groups by excess H+ ions

36. Fungal Hyphae have an important influence on soil structure because they_______________ A: Create large channels that enhance water flow and aeration B: stabilize macro aggregates

B: stabilize macro aggregates

42. This form of sulfur must be oxidize before it can be taken up by plants is ____________. A: elemental sulfur B: sulfide C: sulfate

B: sulfide

14. Drainage pipe comes in 200 ft long rolls. The number of rolls needed to construct a uniform buried drainage system for a nearly level 20 hectare field will depend primarily on_________. A: The Slope of the drain lines B: the texture and structure of the soil

B: the texture and structure of the soil

78. Which of the following statements are correct? A) limestone parent material enhance the process of acidification B) soils on hillsides tend to be deeper than those on level lands C) Alluvial parent materials have been subject to weathering for shorter periods of time than residual parent material nearby

C) Alluvial parent materials have been subject to weathering for shorter periods of time than residual parent material nearby

62. Which of the following irrigation systems is the least efficient method of supplying water? A) drip irrigation B) Sprinkle irrigation C) Furrow-dike irrigation

C) Furrow dike irrigation

66. The process of releases soluble nitrogen as the result of the breakdown of nitrogen rich organic compounds. A) nitrification B) denitrification C) mineralization

C) Mineralization

65. How does the amount of lime needed to neutralize the residual acidity in a clay loam soil compare to that needed to neutralize the active acidity in that soil? A) residual requires 10 times greater B) residual requires considerably less C) Residual requires 5000 times greater

C) Residual requires 5000 times greater

77. The percentage of which soil components represent the minimum information necessary in order to determine textural class? A) sand silt and clay B) Clay and organic matter C) clay and sand

C) clay and sand

87. Wetlands and forests growing along the banks of rivers remove much nitrogen from groundwater by the process of A) nitrification B) immobilization C) denitrification

C) denitrification

76. The negative charges associated with smectite clay crystals are due mostly to A) substitution of Al for Mg in the tetrahedral sheet B) substitution for Al for Si in the tetrahedral sheet C) isomorphous substitution of Mg for Al in the octahedral sheet

C) isomorphous substitution of Mg for Al in the octahedral sheet

71. In a soil at pH 8.0, most of the inorganic P is likely to be in the form of A) Calcium Phosphate b) iron and aluminum phosphates C) phospholipids

C) phospholipids

57. The nomenclature of soil taxonomy is characterized by all but which one of the following statements? A) the names of the orders all end with the letter sols B) the subgroup name also tells you the great group, suborder, and order names C) The names give a clear indication of the modes of genesis of the soil.

C) the names give a clear indication of the modes of genesis of the soil.

13. In order for nitrate to form from soil organic matter, __________ must be present A: Nitrosomonas B: Nitrobacter C: Both of them

C: Both of them (Nitrosomonas & Nitrobacter)

38. In many soil profiles, the subsoil is high in clay, but is also quiet permeable to percolating water. Why? A: The subsoil may have an organic texture B: Clay generally promotes free water movement C: Prismatic structure may be well developed leaving micropores around the structures.

C: Prismatic structure may be well developed leaving micropores around the structures.

34. The R factor of the Universal soil-loss equation is concerned with _________ A: terraces B: climate C: residue cover on the soil

C: residue cover on the soil

88. The universal soil loss equation suggests that soil erosion loss is a product of all but one of the following factors A) climate B) vegetative cover C) sloped steepness D) soil drainage E) slope length

D) soil drainage

61. Which of the following will increase the evaporation from the soil surface? A) plastic mulch B) Stubble mulch farming C) the use of no till D) Adding straw mulch to the soil E) None of the above

E) none of the above

30. Nitrogen is a component of which essential plant compounds? A: proteins B: chlorophyll C: enzymes D: DNA E: All of the Above

E: All of the Above

20. The sulfur dioxide in the atmosphere___________ A: Can be important source of sulfur nutrition for plants B: Is a major contributor to acid rain C: Comes from fire such as fossil fuel burning volcanoes and forest fires D: All of the Above E: None of the Above

E: None of the Above

92. The term ammonium fixation and biological nitrogen fixation refer to the same soil process

False

93. Although only about 2-5 % of the total P in most surface soils is in organic form, this form supplies nearly all the P taken up by plants

False

94. Most nitrogen leaching groundwater is in the form of ammonium

False

95. Nitrification requires the presence of a source of readily available carbon, such as manure

False

96. In most temperate, humid regions, the period of greatest potential for nitrate leaching is during the summer.

False

91. The amount of K lost in subsurface drainage waters from humid region forested watersheds is generally far greater than the amount of P lost in this manner

True