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MSU / Soil Science / PSS 3303 / Which micronutrients increase or decrease in availability when soils b

Which micronutrients increase or decrease in availability when soils b

Which micronutrients increase or decrease in availability when soils b

Description

School: Mississippi State University
Department: Soil Science
Course: Soils
Professor: Jac varco
Term: Fall 2016
Tags: soils and Varco
Cost: 50
Name: Optional Final Study Guide
Description: Covers various questions from the entire semester
Uploaded: 12/06/2016
11 Pages 66 Views 7 Unlocks
Reviews


Exam 4 Study Guide  


Which micronutrients increase or decrease in availability when soils become more acid?



1. A 2:1 type clay mineral is made up of how many of each  layer? 2 tetrahedral:1 octahedral

2. In the octahedral layer, this type of substitution can occur.  

Mg for Al

3. This clay mineral is considered a 1:1 type. Kaolinite 4. The iconic radii of cations are smaller than anions.  5. Calculate the charge (CEC) associated with the following clay  

mineral formula. Also, indicate whether it is negative or  

positive.  

(Si7.8Al0.2)(Al3.4Mg0.6)O20(OH)4 Charge=-1.4


Clay minerals are classified as what?



6. Cation exchange capacity of soil organic matter increases  

with increasing pH.  

7. This soil component potentially has the greatest CEC,  

organic matter.  

8. Calculate the charge (CEC) associated with the following clay  mineral formula. Also indicate whether it is negative or  Don't forget about the age old question of What are barrier islands, and why are they important?

positive.  

K1.4(Si6.4Al1.6)Al4O20(OH)4 Charge= 1.4-1.6=-.2  

9. Differentiate between 2:1 and 1:1 type clay minerals in terms

of layers?  

2:1 (2 tetrahedral:1 octahedral) 1:1 (1 tetrahedral:1  


What are the effects of drainage on soil color?



octahedral)  

10. What ions substitute for each other in tetrahedrals and  

octahedral?  

Tetrahedral: Al for Si Octahedral: Mg for Al

11. Describe pH dependent charge on functional groups of  

organic matter?  

Functional groups supply charge, majority of charge  

from SOM, quantity of charge depends on pH.  12. What is the CEC of clay minerals and soil organic  

matter? Increases with increasing pH  

13. This cation has the greatest charge density and is held  

the tightest by the CEC. Al3+ 

14. This clay mineral is the least weathered and contains  

interlayer potassium. Illite

15. As an acid soil’s pH becomes greater (more alkaline),  We also discuss several other topics like What is the economic model?

the CEC increases.  We also discuss several other topics like Where is the water found on earth?

16. Which of the following indicates chemical equivalents?  

3 cmol Ca2+= 2 cmol Al3+ 

17. Name two sources of pH dependent charge in soils.  

Functional groups-soil organic matter, Al and Fe oxides 18. As soils weather and become more acid, this cation  

increasingly becomes more adsorbed to the soil CEC. Al3+ 19. Functional groups of soil organic matter contribute most

to this type of acidity? Residual  

20. As soils become more acid, availability of this  

micronutrient decreases. Mo  

21. Which of the following indicates chemical equivalents?  2 cmol K+ = 1 cmol Ca2+ If you want to learn more check out What is hang up by eva hesse?

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22. Hydrogen held to functional groups of organic matter,  broken edges of clays, and aluminum and iron  

oxides/hydroxides is considered nonexchangeable.  23. Explain how charge density affects cation adsorption to  

the soil CEC. Strength of attraction depends on charge  

and size of cation.  

24. Differentiate between the 3 types of soil acidity.  a. Active acidity: solution phase H+, ionized from  

organic and inorganic acids including Al hydrolysis.  b. Exchangeable acidity: H+ and Al3+ on exchange  

phase  

c. Residual acidity: non-exchangeable or bond Al3+ and H+. H+ on Al and Fe oxides. Al bound to organic  matter and clays. H bound to functional groups of  We also discuss several other topics like What is the total molecular equation?

SOM and edges of clay minerals.  

25. Which micronutrients increase or decrease in  

availability when soils become more acid?  

Increase: Fe, Cu, Zn, Mn Decrease: Mo

26. Clay minerals are classified as crystalline/secondary.  27. In a tetrahedral layer, this substitution can take place.  

Al for Si

28. A 2:1 clay mineral has 2 tetrahedral sheets.  29. Cations adsorbed to soil colloids are considered  

exchangeable.  

30. Cation exchange capacity of kaolinite is primarily due to pH-dependent charges.  

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31. Soil conditions potentially having the greatest positive  charges present would best be described as highly  We also discuss several other topics like What is ceteris paribus?

weathered-acid pH.  

32. Of the clay minerals, this one would have the greatest  

total surface area, vermiculite.  

33. Due to its effective diameter, this clay mineral would  

not be found in the silt size fraction, smectite.

34. Lack of interlayer space in kaolinite is a result of H

bonding.  

35. Tetrahedral sheets share this oxygen position with  

neighboring tetrahedrals, basal.  

36. This clay mineral is considered to have the greatest  

shrink-swell potential. Smectite  

37. At pH 7.0, this soil component would have the greatest  

CEC. Humus

38. With partial removal of interlayer potassium and the  addition of some silicon, this mineral could form directly from  

muscovite. Illite

39. This clay mineral occurs in both tri- and di-octahedral  

forms. Vermiculite

40. Early weathering of muscovite would would most likely  

result in this type of clay? 2:1

41. Due to its size, this cation fits in the “hexagonal hole”  

within the interlayer of fine-grained micas. K+ 

42. Exchangeable aluminum is best represented by this  species. Al3+ 

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43. Anion concentration in soil dominated by permanent  charge would be the greatest in the diffuse solution  

phase.  

44. Liming an acid soil would have what effect on the CEC?  

Increase it  

45. Through the hydrolysis, how many moles of acidity (H+)  

are produced from one mole of Al3+? Three  

46. Availability of this micronutrient increases with liming or

an increase in soil pH. Molybdenum

47. To be labeled or sold as dolomitic lime in Mississippi,  

the material must contain a minimum of 6% Mg.  48. Exchangeable aluminum is best represented by this ion.

Al3+ 

49. Evidence for the possible influence of man’s activities  

on acid rain occurs at the pH of <5.6.  

50. High soluble levels of this element in lakes interferes  

with oxygen assimilation in the gills of fish. Al3+ 

51. Increasing soil acidity affects the activity of this microbe

the least. Fungi  

52. This soil organism is capable of photosynthesis,  

cyanobacteria.  

53. This organism lives in modified root tissue of legume  

and fixes N2. Rhizobium

54. This temperature is defined as biological zero due to  limited microbial activity, 41°F.  

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55. This group of soil microbes is most active in the  

decomposition of complex woody type plant material, fungi.  56. Which of the following has a eukaryotic cellular  

structure? Algae  

57. This organism is noted for infecting roots and increasing

water and nutrient availability to plants. Mycorrhizae  58. What would be predicted to improve what are referred  

to as “soil health” properties such as biological diversity?  

Cover cropping  

59. The ‘night crawler’ earthworm is noted for its  contribution to improved soil fertility, porosity, and  

aggregation.  

60. Which crop residues would have the highest C:N ratio?  61. When crop residues are added to soil, approximately  

how much of the carbon as CO2 is released back to the  

atmosphere through decomposition? 60%

62. The active organic matter fraction of the A horizon  

would be the lowest in yearly plowed soil.  

63. With increasing depth, the C:N ratio decreases.  64. These soil conditions would result in the greatest soil  

organic matter given all other factors being equal. Poorly  

drained mollisol 

65. Which of the following anions is adsorbed to soil with  

the greatest strength? PO43-

66. Soil fixation of P occurs  

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67. This nutrient is very important for water use efficiency  

and drought resistance. K 

68. These two nutrients contribute to eutrophication of  

bodies of water.  

69. The original mineral source of soil P is Apatite.  70. Net immobilization of soil ammonium and nitrate can  

occur when crop residues added to the soil have a C:N ratio  

of >30:1.  

71. Losses of N as NH3 are more likely to occur when urea  

fertilizer is added to soil with a pH of >7.3.  

72. Organic N in soil and crop residues initially undergoes  

decomposition to NH4+.  

73. In the conversion of NH4+ to No2- , the oxidation state of  

the N changes to +3.  

74. Nodules on the roots of legumes actively fixing N2 from  

the atmosphere have this color. Pink to red 

75. Mineralization of N occurs under these conditions?  

Aerobic and Anaerobic  

76. Nitrogen loss from soil does not occur by this process.  

Immobilization  

77. The degree of eutrophication occurring in fresh bodies  

of water is limited by what nutrient or nutrients?  

78. Which nutrient is most important in energy  

relationships in plants? P 

79. What is the mobility of potassium in plants? Mobile  80. Nitrogen is added to soil through rainfall because of  

electrical discharge.  

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81. When crop residues are added to soil, approximately  how much of the carbon as CO2 is released back to the  

atmosphere through decomposition 60 to 80 %.  

82. The valence state of N in NO3- is +5.  

83. With increasing soil depth, the C:N ratio decreases.  84. Given all other soil conditions are the same, which soil  

drainage class would result in the greatest organic matter  

content? Poorly-drained. 

85. The Mississippi State Extension Service Soil Testing Lab  

reports available S based on what? % of organic matter  86. Expressed as CEC, a soil containing 3200 lb Ca2+/ acre  

would have how many cmolc/kg attributed to this cation? 8.0  87. Typically this nutrient is the most limiting factor for  

eutrophication of bodies of freshwater in the US? P 88. This plant nutrient is noted for its role in drought  

tolerance. K 

89. The most strongly fixed soil P is found in this form in  soil. Inner sphere adsorbed.  

90. The type of structure for the classification “strong  medium angular blocky” is angular blocky.  

91. This soil order comprises the most acreage in the  southeastern U.S. , Ultisol.  

92. Soil material that has an effective diameter of 0.5- to  1.0-mm would be classified as ______________.  

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93. The soil textural class ‘loam’ most accurately describes  the soil texture where the soil separates are equal in their  contribution to soil physical properties.  

94. For a given volume of soil, as particle size decreases  surface area increases.  

95. What are the effects of drainage on soil color? Reds  are good drainage, Yellow intermediate drainage ,  Greys are poor drainage  

96. Explain the difference between dispersion and  flocculation of soil particles. Dispersion is the separation  of soil particles; flocculation is the joining of soil  particles.  

97. Define macropores and micropores relative to drainage?

98. What are the effects of soil texture on bulk density; 5.  Pore size distribution?  

99. This soil color would indicate poor drainage and the  presence of reduced iron…grey.  

100. Excessive quantities of this cation in soil causes the  greatest dispersion. Na+ 

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101. The diameter of micropores is considered to be less  than 0.08 mm.  

102. Which of the following pore size distributions (ratio of  macro to micropores) might indicate a coarse or sandy soil  texture? 65/35  

103. In their native well aggregated state, this soil textural  class generally has the lowest total pore space. _____________.

104. Field capacity occurs at a soil water potential of -0.33  bars.  

105. A soil with a bulk density of 1.42 g/cm^3 and holds  26% volumetric (Pv) at field capacity would have a  macropore space of approximately 20%.  

106. Hydraulic conductivity (K) of soils depends greatly on  soil texture and water content.  

107. For three soils, all at a water potential of -0.3 bars, this  texture would have the greatest volumetric water content.  Clay loam  

108. All capillary water in soil is considered to be plant  available. True  

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109. Available water occurs within the soil water tension  ranges of -0.1 to -15 bars.  

110. A soil with a bulk density of 1.27 g/cm3 and holds 32%  volumetric water (Pv) at field capacity would have a  macropore space of approximately what? (1- 

 (1.27/2.56))x100=50.4 then 50.4- 32=18% so   ≅ 20%  

111. Hydraulic conductivity (K) of soils depends greatly on  soil texture and water content.  

112. For three soils all at a water potential of -0.3 bars, this  texture would have the lowest volumetric water content  sandy loam.  

113. Capillary water occurs in micropores only.  11

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