CSES 2040: Exam 2

The concentration of soil CO2 is about _____ than the atmospheric air. a. 10-100x greater b. 1000x less c. 10,000x greater d. 100,000x greater

a. 10-100x greater

If pH of a soil is7, its pOH will be: a. 7 b. 14 c. 6 d. a and b

a. 7

Which of the following liming material has the highest calcium carbonate equivalent (CCE) relatively? a. CaO b. Ca(OH)2 c. CaMg(CO3)2 d. CaCO3

a. CaO

90% of the cells in our bodies belong to microbes. a. True b. False

a. True

Active soil acidity is a measure of the H+ ion activity in the soil solution. a. True b. False

a. True

Alkalinity, salinity, and sodicity are common problems in arid and semiarid soils. a. True b. False

a. True

As soil depth increases, CO2 concentration will increase in dry or wet seasons. a. True b. False

a. True

As the intensity of weathering on clay minerals increases, its cation exchangeable capacity decreases. a. True b. False

a. True

ESP, ESR and SAR are measures of sodium status in soils. a. True b. False

a. True

Evapotranspiration includes water losses both from soul surface and plants. a. True b. False

a. True

Gypsum is the most widely used chemical for the reclamation of sodic soil because of its abundance and low price. a. True b. False

a. True

The approximate residence time for a water molecule in the cloud is: a. 2 days b. 10 days c. 10 years d. b and c

b. 10 days

________ is a biochemical reduction of nitrate to gaseous nitrogen or other oxides of nitrogen that causes about 30% of the total loss of nitrogen from agricultural fields. a. Nitrification b. Dentrification c. ammonification d. none of the above

b. Dentrification

A 2:1 type silicate clay has one octahedral sheet sandwiched between two tetrahedral sheets while 1:1 silicates have one tetrahedral sheet and one interlayer unit. a. True b. False

b. False

Alkaline soils have more OH-, HCO3-, CO3--, and H+ than acidic soils. a. True b. False

b. False

The process of aerobic respiration is a significant source of: a. methane b. oxygen c. nitrogen d. carbon dioxide

d. carbon dioxide

Which soil water potential represents the dries soil condition? Under these conditions, water would likely move via matric forces. 30 kPa 10 kPa -10 kPa -30 kPa 0 kPa

-30 kPa

What is the gravimetric water content of a soil with 167 g moist weight and a 100 g dry weight? 0.25 g/g 0.65 g/g 0.50 g/g 0.67 g/g

0.67 g/g

If a watershed received 1000 mm of rain during a year, stored 300 mm of water in the soil, and lost 200 mm due to leaching & runoff (i.e., discharge), then ________mm of water was likely lost to the atmosphere through evapotranspiration 600 mm 300 mm 500 mm 200 mm 1000 mm

500 mm

Which statement is true regarding microbial activity? Aerobic conditions stimulate the most rapid and complete degradation of organic residues Microbial activity is highest at very low and very high temperatures Microbes grow best when there are few organic residues None of these answers are correct Anaerobic conditions stimulate the most rapid and complete degradation of organic residues

Aerobic conditions stimulate the most rapid and complete degradation of organic residues

When residues with a ______ are added to a soil, N can be _________ making it relatively unavailable for plant uptake Low C/N; immobilized Low C/N; mineralized High C/N; mineralized High C/N; immobilized

High C/N; immobilized

Saturated water flow is best described by which of the following answers? Movement of water due to capillary or matric water potential Movement of water primarily in micropores Movement of water in earthworm channels, cracks, and other macropores Movement of water primarily through macropores due to gravitational forces Movement of water only when the soil is near the permanent wilting point

Movement of water primarily through macropores due to gravitational forces

Which of the following statements best describes humic substances? Non-living organic compounds that cannot be identified as to where it came from, but you can identify the compound biochemically Non-living organic compounds that cannot be identified as to where it came from and the compounds cannot be identified either Non-living tissue that can be identified as to where it came from Living organisms in the soil

Non-living organic compounds that cannot be identified as to where it came from and the compounds cannot be identified either

Which of the following statements best describes detritus? Non-living organic compounds that cannot be identified as to where it came from All of these answers describe detritus Non-living tissue that can be identified as to where it came from Living organisms in the soil

Non-living tissue that can be identified as to where it came from

Which of the following are plant processes that are NOT affected by temperature? None of these answers because all answers are processes affected by temperature Root Growth Water uptake Germination Correct Answer Nutrient uptake

None of these answers because all answers are processes affected by temperature

The effect of a gravel or very sandy horizon in a soil below a clay horizon will likely _____ Prevent water from draining into the sandy horizon until the soil above is saturated Not affect water movement in the soil because water movement is due to gravity only Cause water to drain more quickly through the soil to groundwater Not affect water movement in the soil because water movement is due to capillary forces only

Prevent water from draining into the sandy horizon until the soil above is saturated

Under which condition would you expect to find the highest soil organic matter levels? Soils in wet, cool climates under native vegetation Soils with good drainage and aeration Soils in dry, warm climates under cultivation Soils with high intensive cultivation and tillage

Soils in wet, cool climates under native vegetation

Which of the following is true about the global carbon cycle? There is more C in the soil than in all the plants in the world The largest pool of C is the CO2 in the atmosphere Carbonate rocks represent the largest pool of C and this pool is rapidly cycling with the atmosphere The ocean is a large reservoir of C, but the C does not cycle into other pools

There is more C in the soil than in all the plants in the world

A photoautotroph _______ Uses CO2 from the atmosphere and light under aerobic conditions to make their own energy Consumes plants to get their energy Consumes nematodes and bacteria to get their energy Uses N, S, or Fe under anaerobic conditions to make their own energy

Uses CO2 from the atmosphere and light under aerobic conditions to make their own energy

I am still trying to grow a regular palm tree in Auburn, Alabama even though it grows in Mobile, Alabama with ease. This is mainly due to the differences in temperature zones. a. True b. False

a. True

Just before you reach Mobile Bridge driving on I-65 S, you will see a sign that reads: 'Wetland". If you were able t dig a pit to examine the color of the soil profile, it would probably be grayish due to prevailing reduction conditions. a. True b. False

a. True

Microbial population is positively related to soluble food sources. a. True b. False

a. True

Most of the salt affected soils of the contiguous US lies west of the Mississippi River. a. True b. False

a. True

Oxidation of ammonium (NH4+) to nitrite (NO2-) and then to nitrate (NO3-) are accomplished by nitrosomonas and nitrobacter bacteria, respectively. a. True b. False

a. True

Soil pH is a master variable because it affects many biochemical reactions in soils. a. True b. False

a. True

The two main sources of charges in soil are the permanent (constant) charge and the pH dependent charge. a. True b. False

a. True

Water evaporation leads to salt accumulation since salt does not evaporate under normal conditions. a. True b. False

a. True

Cation exchangeable capacity is a measure of: a. cations held on soil colloid exchangeable sites b. anions held on soil colloid exchangeable sites c. a and b d. none of the above

a. cations held on soil colloid exchangeable sites

If potential evapotranspiration in a given watershed is much greater that precipitation, you will have water: a. deficit b. discharge c. neither deficit nor discharge d. a and b

a. deficit

Irrigation type with the least field water use efficiency would be: a. flood irrigation b. sprinkler irrigation c. drip irrigation d. all are about the same

a. flood irrigation

Comparatively, which of the following soil colloid contains the highest amount of negative charge (Cmolc/kg)? a. soil humus (organic matter) b. kaolinite c. semectite d. vermiculite

a. soil humus (organic matter)

Which organism is a bacteria that is very fungi-like and are important in degrading organic matter. Some can even fix their own N from the atmosphere? Actinomycetes Bacteria Fungi Protozoa Mycorrhizae

actinomycetes

The best management practice(s) to prevent surface evapotranspiration is(are) all of the practices listed can prevent evapotranspiration weed control irrigation increased seeding rate covering the soil with mulch

all of the practices listed can prevent evapotranspiration weed control

Water could move upward in a soil profile due to ____________ All of these answers could cause water to move upward in the profile because they describe capillary water movement. Matric potential if the surface has a finer texture than the subsoil Matric potential if the surface soil is drier than subsoil The water potential is greater in the subsoil than at the surface

all of these answers

Which of the following is likely to affect the growth of microorganisms? Soil organic matter content Soil oxygen content All the answers are correct Soil oisture and temperature Soil pH

all the answers are correct

Which of the following is true about humus? All the answers are correct Higher surface area than clay Negatively charged due to carboxylic acid groups and other acidic functional groups Has a higher water holding capacity than clay Typically black colored

all the answers are correct

Which of the following are the major factors that affect microorganism species and population numbers? All the answers are major factors affecting microorganisms Chemical properties of the environment (e.g., pH, nutrient availability) Aeration, water, temperature conditions Type and abundance of food

all the answers are major factors

If you dissolve 200g of salt in 1000mL of water and added to your plant, and 700mL of the solution is lost by evapotranspiration, the amount of salt left in the solution will be: a. 900g b. 200g c. 500g d. 300g

b. 200g

Genetically engineered organisms are dangerous and should never be allowed in any ecosystem. a. True b. False

b. False

If you want to decrease your soil pH very fast, elemental sulfur (S) will be your best choice. a. True b. False

b. False

In 2:1 silicate minerals, one tetrahedral sheet is sandwiched between two octahedral sheets. a. True b. False

b. False

In isomorphus substitution, atoms of similar size replace each other without disrupting the crystal structure and without affecting the net charge of the mineral. a. True b. False

b. False

Since flora are doing most of organic matter decomposition, the role of fauna is unimportant. a. True b. False

b. False

Sodic soil can be reclaimed by adding NaCO3 and CaCO3. a. True b. False

b. False

The partial pressure CO2 is greater in the soil air. Therefore, CO2 will diffuse from air atmosphere to soil. a. True b. False

b. False

After defeating the Carthaginian army, what did the Roman army do to the fertile fields of the Carthage some 2100 years ago? a. added concentrated acid to lower pH b. added salt to degrade the land c. added fertilizer to grow more wheat d. planted cotton to demonstrate use of irrigation

b. added salt to degrade the land

Under optimum conditions, as temperature increases by 10C, bio chemical reactions will: a. increase 100x b. double c. decrease 10x d. none of the above

b. double

Liming will help to acidify soils by producing H+ and decreases soil pH. a. True b. False

b. false

The CEC of an organic soil will: a. decrease as pH increases b. increase as pH increases c. remain the same d. none of the above

b. increase as pH increases

Soils rich in which type of colloids would provide the most suitable material on which to build homes and/or roads? a. humus b. kaolinite c. smectite d. all are about the same

b. kaolinite

Which of the following substitution creates a net negative charge on a neutral soil? a. one Ca+2 ion for one K+1 ion b. one Al+3 ion for one Si+4 ion c. one Al+3 ion for one Fe+3 ion d. all of the above

b. one Al+3 ion for one Si+4 ion

A given soil has significant amount of NH4+ on its exchangeable sites from NH4+ application. If you use NH4+ to displace the cations and measured the CEC by summation of the displaced cations, you will _______ CEC of the soil. a. overestimate b. underestimate c. estimate the correct d. none of the above

b. underestimate

Ammonium acetate is used to determine soil CEC that was fertilized with NH4+ by the displacement method. In this situation, the correct CEC will be: a. overestimated b. underestimated c. the same, no change d. none of the above

b. underestimated

A soil at pH 4.0 will have ______ H+ activity compared to a soil at pH 8.0. a. 4000x more b. 4000x less c. 10,000x more d. 10,000x less

c. 10,000x more

A soil with a pH of 5.0 has __________ H+ compared to a soil with a pH of 7.0. a. 2x b. 200x c. 100x d. 1000x

c. 100x

An alkaline soil contains 20% clay and 3% humus. If the pure clay has a CEC of 40cmolc/kg and the humus 200cmolc/kg, calculate the CEC (cmolc/kg) of the soil. a. 8 b. 30 c. 14 d. 16

c. 14

Of the water that participates in the human-scale hydrologic cycle, ________ of the water resides in the soil. a. 60% b. 50% c. 33% d. 10%

c. 33%

The relative of which two gasses can be an indication of soil aeration? a. N2 and Cl2 b. N2 and O2 c. O2 and CO2 d. N2 and O2

c. O2 and CO2

Sodic souls generally have a poor physical condition due to: a. low organic matter content b. impacts of raindrops on the soil surface c. dispersal of the Na saturated soil colloids d. precipitation of the Ca2+ and Mg2+ ions as carbonates

c. dispersal of the Na saturated soil colloids

A wet soil is not a good insulator compared to dry soil because it relatively has: a. low specific heat capacity b. low thermal conductivity c. high thermal conductivity d. none of the above

c. high thermal conductivity

Oxygen availability in soil is affected by all of the following except: a. macroporsity b. water content c. nitrogen gas content d. redox potentiol

c. nitrogen gas content

All of the following parameters define the water balance equation in a given watershed except: a. precipitation b. discharge c. radiation d. soil storage

c. radiation

If a growing plant root takes K+1, NH4+1, and SO4-2 from soil solution concurrently, the pH of the solution will: a. increase b. decrease c. remain the same d. cannot be determined

c. remain the same

Complete degradation of an organic compound under aerobic conditions should produce_____ oxygen (O2) carbon monoxide (CO) methane (CH4) carbon dioxide (CO2) ammonia (NH3)

carbon dioxide (CO2)

Which soil is likely to have the lowest saturated hydraulic conductivity (Ksat)? Clay (well aggregated) Sand Silt loam Sandy clay Clay (poorly aggregated)

clay (poorly aggregated)

What is a humus-like organic material that is produced outside the soil by mixing, piling, or storing organic materials under conditions favoring aerobic decomposition and nutrient conservation? Compost Biomass Green manure Soil organic matter Manure

compost

________ is the amount of cation charges that a soil can hold at its natural or apparent pH. a. CEC at pH=7.0 b. neutral pH c. CEC at pH=8.2 d. Effective CEC

d. Effective CEC

Liquid water losses from soil will include: a. percolation/leaching b. TMDL c. runoff/erosion d. a and c

d. a and c

In the absence of free O2, which of the following elements (molecules) can act as terminal electron acceptors? a. NO3 b. SO4 c. CO2 d. all of the above

d. all of the above

Soil colloids are: a. a very small size b. very large surface area c. sites for cation/anion exchange capacity d. All of the above

d. all of the above

The concentration of which of the following elements will increase as soil pH decreases from 6.0 to 4.0. a. Mn b. Fe c. Zn d. all of the above

d. all of the above

Under conditions where there is no free 02 in the soil, soil microbes may use ________ as an electron acceptor for oxidation. a. SO4-2 b. Fe+3 c. Mn+4 d. all of the above

d. all of the above

Which of the following is a function of soil microbes? a. fix atmospheric N2 b. produce antibiotics c. mineralize N, P, and S d. all of the above

d. all of the above

A dry soil is a good insulator because it has: a. high thermal conductivity b. low thermal conductivity c. high heat capacity d. both b and c

d. both b and c

The two sources of negative charges in silicate minerals are: a. isomorphus substitution and temporary charge b. isomorphus substitution and permanent charge c. isomorphus substitution and water dependent charge d. isomorphus substitution and pH dependent charge

d. isomorphus substitution and pH dependent charge

If you want to reclaim a saline soil, which of the following practices would you most likely use? a. add CaCO3 to reduce the exchangeable Na+ level b. leach the soil with water high in bicarbonates c. leach the soil with water having a high SAR ratio d. none of the above

d. none of the above

The main reason AL, GA, and FL have conflict sharing their common water resource is due to: a. taxation of water transportation b. drug trafficking c. water pollution d. none of the above

d. none of the above

The composting process results in a _______ Decrease in pH Increase in C/N ratio Decrease in C/N ratio Decrease in ash content

decrease in C/N ratio

There are three types of humic substances, which can be described as a group of molecules without a definite structure that is soluble, small in size, and highly reactive compared to other humic substances? Humus Correct Answer Humic acid Fulvic acid Humin

fulvic acid

Percolation of water via saturated flow in soils occurs primarily due to differences in _____ Capillary potential Gravitation potential Soil moisture tension Gravitational and osmotic potential Osmotic potential

gravitation potential

Which of the following contributes to runoff more than infiltration? Low intensity rainfall for long durations Low intensity rainfall for short durations High intensity rainfall for long durations High levels of vegetation Good soil structure

high intensity rainfall for long durations

Which of the following is a good general practice to maintain or improve soil organic matter? Replace native perennial vegetation with annual row cropping systems Fallow winter fields Remove vegetation whenever possible Minimize crop removal when harvesting Deep tillage practices that incorporate any surface residues into the soil

minimize crop removal when harvesting

Which of the following represents the practice of adding plant residues to enrich agricultural soils by planting as a cover crop that is not harvested? Green manuring Manuring Mychorrhizae Composting Mulching

mulching

Which organism(s) represents a symbiotic relationship between fungi and plant roots? algae nitrogen fixation actinomycetes nematodes mycorrhizae

mycorrhizae

Which of the following are primary producers? most fungi termites Birds (e.g., robins, eagles, hawks) Plants

plants

Which of the following represents the quantity of water in a soil when both macro and micro pores are full of water? All of the answers are correct Saturation Hydroscopic capacity Maximum retentive capacity Field capacity

saturation

A bunch or organic materials are deposited on the ground. Which of the following organic compounds will be degraded first (i.e., they are the easiest compounds to degrade)? protein Sugars and starches Fats, waxes, oils Lignin polyphenols (tannins)

sugars and starches

The energy that drives the hydrologic cycle comes from _____ the sun lightening rainfall fossil fuels hydroelectric power

the sun

Which of the following is best described as the unsaturated zone, which is located between the land surface and the top of the groundwater? Vadose zone Aquifer Groundwater Soil profile Water table

vadose zone