Soil Science Final Exam Walter State/1050-1051
Colloidal properties are exhibited by the ___ fraction of soils. 1) gravel 2) sand 3) silt 4) clay
clay
Which of the following is not a textural class name? 1) sand 2) silt 3) loam 4) clay 5) sandy silt
sandy silt
Igneous, sedimentary, and metamorphic are three _________. types of rocks basic classes of soils master horizon names forms of minerals processes of weathering
types of rocks
Which of the following sources of water have the shortest average residence time? 1) Soil moisture 2) Clouds. 3) Oceans and ice caps 4) groundwater
Clouds
Which of the following is (are) essential plant nutrients? Cu Sr Pb Al All of the above
Cu
Soils in this order are commonly sandy in texture, quite acidic and develop primarily under coniferous trees in cool to cold climates 1) Mollisols 2) Andisols 3) Spodosols 4) Alfisols 5) Ultisols
Spodosols
Which of the following will not increase the efficiency of water use by plants in an irrigation system? 1) The use of concrete-lined delivery ditches 2) The use of flood irrigation for forage crops 3) The use of drip irrigation for fruit trees 4) The use of crop residues to reduce evaporation 5) The use of herbicides to control weeds
The use of flood irrigation for forage crops
Which of the following is not true with respect to the hydrologic cycle? 1) More than 85% of the water evaporated from the earth's surface comes from oceans. 2) There is a net migration of some 40,000 km3 of water in clouds from the land area to the ocean areas. 3) The average residence time of water in clouds is about 10 days. 4) Some 78% of the total precipitation falls onto the oceans. 5) About one third of the readily accessible water in the hydrologic cycle is in the soil.
There is a net migration of some 40,000 km3 of water in clouds from the land area to the ocean areas.
The element most often involved in oxidation reactions as minerals weather is _____. copper Silicon Aluminum Magnesium Iron
Iron
The following is the reduced form of the essential element depicted 1) NH4+ 2) Fe3+ 3) CO2 4) SO42- 5) Mn4+
NH4+
A well aerated soil is characterized by a relative abundance of _____. 1) micropores 2) Fe2+ions 3) NH4+ ions 4) NO3- ions 5) methane gas
NO3- ions
To be practical, a nitrification inhibitor should kill or inhibit _____. 1) Nitrosomonas 2) Nitrobacter 3) either A or B 4) none of the above
Nitrosomonas
Organic matter accumulation is most pronounced in the ____. O horizon A horizon E Horizon B Horizon C Horizon
O horizon
The nutrient most often limiting the growth of aquatic plants and algae in unpolluted fresh water lakes is ______. 1) N 2) S 3) P 4) K 5) none of the above
P
In acid soils the principal chemical form of phosphorus available for plant uptake is ____. 1) P2O5 Incorrect Response 2) H2PO4- Correct Answer 3) P3+ 4) HPO42- 5) P3-
P3+
Typical well drained, well developed soil in Northeast Tennessee will most likely be classified as a: 1) Ultisol 2) Vertisols 3) Inceptisols 4) Histosols 5) Gelisols
Ultisol
Which group of soil organisms includes the largest number of autotrophic species? 1) bacteria 2) fungi 3) actinomycetes 4) detritivores 5) protozoa
bacteria
A deficiency of N typically ______ the maturity of annual plants. 1) hastens 2) delays 3) does not affect
hastens
The matric potential of soil water is _____. 1) influenced greatly by the content of salts in the soil 2) not influenced appreciably by the force of gravity 3) is generally higher than that of pure water outside the soil 4) is little affected by soil solids 5) is lower in a sandy soil with 20 percent soil water than in a clay soil with same percentage of moisture
not influenced appreciably by the force of gravity
Unsaturated water flow _____________. 1) is faster than saturated flow 2) is driven primarily by the force of gravity 3) is stimulated by the osmotic potential 4) is slower on sands than on clays if the soil moisture content is high 5) occurs on soils that are at field capacity
occurs on soils that are at field capacity
The great majority of nitrogen (95 to 98%) in soils can be found in the form of _____. 1) primary minerals 2) secondary minerals 3) dissolved cations 4) dissolved anions 5) organic compounds
organic compounds
Organisms which use carbon dioxide or carbonates for their carbon source and either sunlight or inorganic chemicals for their energy source are called ____. 1) facultative anaerobes 2) heterotrophs 3) detritivores 4) autotrophs 5) actinomycetes
autotrophs
Methemoglobinemia is principally a potential threat to _____. 1) babies drinking water high in sulfate 2) adults drinking water high in sulfate 3) babies drinking water high in nitrate 4) adults drinking water high in nitrate 5) all of the above
babies drinking water high in nitrate
Topsoil is generally equivalent to which soil horizon? A B C R E
A
Subsoil is generally equivalent to which soil horizon? A B C R E
B
Silicate clay accumulation is most common in the ____. O horizon A horizon B horizon C horizon E horizon
B horizon
After drying to eliminate the water in plant litter, which two elements account for about 80% of the dry weight? 1) N and C 2) N and S 3) C and H 4) C and O 5) Ca and C
C and O
Which of the following pH values represents the most acid condition? 1.0 7.0 14.0 8.5 3.5
1.0
Which color would be typical of a well drained, low-organic matter sandy surface soil? 1) 10YR5/8 2) 7.5YR6/2 3) 2.5YR6/1 4) 7.5YR2/2 5) 10YR8/4
10YR5/8
To avoid a nitrate depression period when it is added to a garden soil, about how many kg of nitrogen must be added to a load of grass clippings that contains 1000 kg of C and 25 kg of N? 1) 15 2) 35 3) 50 4) 75 5) 100
15
Suppose leaves containing 1000 kg of carbon fell to the forest floor in a humid temperate environment. After a year or so, how many kg of that carbon would you expect to remain in the soil as microbial biomass and humus? 1) 10 2) 20 3) 200 4) 400 5) 800
200
Approximately what percentage of the P in surface soils is typically found in organic forms? 1) 0.1 to 0.5% 2) 1 to 5% 3) 5 to 15% 4) 25 to 75% 5) 95 to 98%
25 to 75%
Other things being equal, a soil with 30% clay of the ____ type would be expected to have the greatest phosphorus -fixing capacity. 1) allophanic 2) 2:1 3) 1:1 4) crystalline iron oxide
2:1
Grass clippings from a healthy lawn can be expected to contain approximately ___% N (on a dry weight basis). 1) 0.01 2) 0.2 3) 0.5 4) 3.0 5) 7.5
3.0
Which of the following added to a soil would be likely to result in the greatest level of soil organic matter after several years of decomposition? 1) 5 Mg of carbon in plant roots 2) 5 Mg of carbon in plant tops 3) the manure produced by feeding cattle 5 Mg carbon in plant residues 4) the compost produced by composting 5 Mg of plant leaf material.
5 Mg of carbon in plant roots
In a field experiment you noted that 300 tons of water was transpired to produce 1 ton of corn (dry weight). If alfalfa had been grown in the same field instead of corn, which of the following would most likely have been the amount of water transpired? 1) 500 tons 2) 300 tons 3) 275 tons 4) 250 tons 5) depends on the climate in the area of the experiment
500 tons
Which of the following pH values represents a neutral condition?
7
Green plant residues such as grass clippings or a green manure crop generally have a water content of about ____% by weight. 1) 10 2) 25 3) 45 4) 75 5) 95
75
Assume an A horizon depth of 15 cm. A well drained silt loam soil on an Iowa farm has 3.5% organic matter which is about 5% N. Estimate the kg/ha of nitrogen that this soil horizon will make available for plant use from soil organic matter in one year (without the addition of fertilizer). 1) 17.5 2) 88 3) 263 4) 175 5) 38
88
Which cation would you expect to be mostly tightly held in a soil at pH 4.5? 1) K+ 2) Ca2+ 3) Al3+ 4) Mg2+ 5) Na+
Al3+
Which of the following would you expect to have the highest leaf area index? 1) Bare fallowed area 2) Corn three weeks after planting 3) Corn, knee high 4) Alfalfa just before harvest 5) Either B or C (equal)
Alfalfa just before harvest
Secondary minerals are most prominent in the fraction of soils. organic Sand Silt Clay
Clay
In which soil orders would recent alluvium most likely be a common parent material? 1) Ultisols 2) Entisols 3) Andisols 4) Alfisols 5) Aridisols
Entisols
Soil order characterized by permafrost is known as: 1) Alfasols 2) Vertisols 3) Inceptisols 4) Histosols 5) Gelisols
Gelisols
If the soils are to be used for crop production, for which soil order would land drainage be most critical 1) Mollisols 2) Inceptisols 3) Aridisols 4) Oxisols 5) Histosols
Histosols
The following are true characteristics of a water molecule. 1) The H to O to H angle is approximately 90o C. 2) The two H atoms are on diametrically opposite ends of the molecule. 3) It has a positive and a negative side. 4) It is attracted to surfaces with negative but not positive charges. 5) It is held in soils by adhesion but not adsorption.
It has a positive and a negative side.
In acid soils the principal chemical form of potassium available for plant uptake is ____. 1) K2O 2) H2KO2- 3) K+ 4) HKO22- 5) P-
K+
Wind blown silt sized materials is known as: Silt Glacial Loess Lacustrine Residual
Loess
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? 1) Mollisol 2) Alfisol 3) Ultisol 4) Entisol 5) Vertisol True or false questions
Mollisol
Soil colors are scientifically described by ____ color designations such as 10YR3/4. 1) USDA 2) wavelength 3) Parson's 4) Munsell 5) structural
Munsell
Soil scientists from which country first conceived the idea that soils were natural bodies? 1) United States 2) France 3) Russia 4) Great Britain 5) Belgium
Russia
Most of the different nutrients essential for growth are supplied to plants directly from the ______. Rain Water Soil Solution Cosmic Radiation Atmosphere Humus
Soil Solution
Which of the following does not describe aluminum hydroxy ions (such as Al(OH)2+) in the soil? 1) They are more prominent in acid than in neutral soils. 2) They affect the pH of the soil solution through hydrolysis. 3) They block negative sites on some clays thereby reducing the cation exchange capacity. 4) They influence the swelling of some clays by entering into the interlayer spaces. 5) They are commonly applied to help reduce the soil pH for acid-loving plants.
They are commonly applied to help reduce the soil pH for acid-loving plants.
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? 1) Aridisol 2) Oxisol 3) Vertisol 4) Mollisol 5) Ultisol
Vertisol
Soil order characterized by high swelling capacity clays is known as: 1) Alfasols 2) Vertisols 3) Inceptisols 4) Histosols 5) Gelisols
Vertisols
Ammonia losses are likely to be greatest if a nitrogen source is placed about 10 cm deep in ____ 1) an acid, sandy loam soil 2) a calcareous sandy loam soil 3) an acid, clay loam soil 4) a calcareous clay loam soil
a calcareous sandy loam soil
A soil pedon is ____. 1) a category of Soil Taxonomy 2) a three-dimensional unit that embodies the primary characteristics of an individual soil 3) generally larger in area than a polypedon 4) a diagnostic subsurface horizon prominent in arid regions and in sandy parent materials. 5) a surface horizon used to characterize soil suborders and great groups
a category of Soil Taxonomy
You would be most likely to find P deficient plants in which location? 1) a vegetable garden in India 2) a corn field in sub-Saharan Africa 3) a pasture in the Netherlands 4) a Douglas Fir forest in Oregon 5) an apple orchard in New York.
a corn field in sub-Saharan Africa
If you wanted to find a soil where physical weathering dominated over chemical breakdown you would be most apt to find it in ______. a desert region of Arizona a humid region in Brazil the hill lands of Georgia a lacustrine deposit in Minnesota a coastal plain area of Delaware
a desert region of Arizona
Which of the following locations in the United States would have the highest evaporation (E) from the soil surface in July? 1) a bare, unirrigated dry land soil in Colorado 2) an unirrigated soil in South Carolina growing cotton 3) a furrow-irrigated cotton field in Arizona 4) a forest woodland in Illinois 5) a corn field in New York
a furrow-irrigated cotton field in Arizona
Argillic horizons are characterized by ___. 1) accumulation of silicate clays 2) high level of Na+ ions 3) high levels of iron and aluminum oxides 4) impervious hardpan layers 5) organic matter accumulation
accumulation of silicate clays
Because of their greater surface area per unit of soil mass, silt loams soils generally have a greater capacity than loamy sand soils to ___. 1) adsorb water 2) adsorb gases 3) release nutrients by mineral weathering 4) support bacterial growth 5) all of the above
all of the above
In nature, beneficial mycorrhizae form with the roots of _____. 1) coniferous trees 2) grasses 3) legumes 4) broad leaf trees 5) all of the above
all of the above
Nitrogen is a component of which essential plant compounds? 1) proteins 2) chlorophyll 3) enzymes 4) DNA 5) all of the above
all of the above
Plants obtain nitrogen from the soil by taking up ______. 1) soluble anions 2) soluble cations 3) soluble organic compounds 4) all of the above 5) none of the above
all of the above
The sulfur dioxide in the atmosphere ______. 1) can be an important source of sulfur nutrition for plants 2) is a major contributor to "acid rain" 3) comes from fires such as fossil fuel burning, volcanoes and forest fires 4) all of the above 5) none of the above
all of the above
The water in the soil typically differs from pure water because the soil water ________. contains organic compounds contains mineral nutrients is restrained in its flow by attraction to particle surfaces all of the above none of the above
all of the above
Which of the following is (are) major sources of the carbon dioxide now being added to the atmosphere in excess of the amount taken out by plants? 1) loss of soil organic matter 2) burning of fossil fuels 3) destruction of natural forests 4) all of the above 5) none of the above
all of the above
Which of the following is a greenhouse gas contributed to the atmosphere by soils? 1) nitrous oxides 2) carbon dioxide 3) methane 4) all of the above 5) none of the above
all of the above
Which of the following practices is(are) useful in stabilizing surface soil structure? 1) use of organic mulches 2) use of green manure crops 3) growing grass sod 4) minimizing tillage 5) all of the above
all of the above
The presence of rocks such as shale and sandstone indicate the existence of _______. a high water table ancient seas old mountain ranges iron-rich minerals highly weathered soils
ancient seas
In order for nitrate to form from soil organic matter, _____ must be present in the soil. 1) Nitrosomonas 2) Nitrobacter 3) either A or B 4) both A and B 5) none of the above
both A and B
In various parts of the world, soil phosphorus is associated with which of the following environmental problems? 1) soil degradation because of depletion of soil phosphorus Incorrect Response 2) eutrophication of lakes because of a build-up of soil P in the watersheds 3) toxic levels of phosphate in groundwater supplies Correct Answer 4) both A and B 5) all of the above
both A and B
The transformation of gneiss into mica, quartz, and feldspar crystals is an example of Incorrect Response physical weathering chemical weathering disintegration hydrolysis Correct Answer both A and C
both A and C
Compared to land that is not disturbed by tillage, conventionally plowed cropland usually loses much more ______. 1) dissolved P 2) particulate P 3) total P 4) both B and C are correct 5) none of the above is correct
both B and C are correct
Plant roots obtain access to soil water in which of the following ways? 1) The roots contract and leave room in the pores for the water to move in. 2) Roots extend into moist soil area. 3) Water vapor moves from the wet soil areas to the root surfaces. 4) Water flows to the roots by capillarity. 5) both B and D True or False Questions
both B and D
Plant transpiration efficiency at a given location is markedly influenced by _____. 1) organic residue cover on the soil 2) tillage practices used 3) fertilization practices used 4) the plant species being grown 5) both C and D
both C and D
If you want to quickly (in just a few days) increase the pH of a soil from 5.5 to 7.0, which of the following would you use? 1) sawdust 2) calcitic limestone 3) dolomitic limestone 4) burned lime 5) ammonium nitrate
burned lime
Humus is an important soil colloid. It differs from 2:1 type minerals in all but one of the following characteristics (select the one). 1) structural framework of the particles 2) CEC dependence on soil pH 3) influence of isomorphous substitution 4) capable of adsorbing cations 5) influence on soil aggregate stability
capable of adsorbing cations
Nearly all organic compounds from which living beings are made have as their backbone, chains or rings of _____ atoms. 1) aluminum 2) oxygen 3) carbon 4) nitrogen 5) none of the above
carbon
The process of aerobic respiration is a significant source of which of the following gases? 1) methane 2) oxygen 3) nitrogen 4) carbon dioxide 5) ammonia
carbon dioxide
If a dry soil high in certain types of ____ is moistened, it is likely to swell up with enough force to crack pavements and building foundations. 1) humus 2) iron 3) clay 4) silt 5) any of the above
clay
The mixed angular gravel, rock, and soil found at the foot of a slope is typical of what type parent material? eolian colluvial fluvial glacial lacustrine
colluvial
Glacial till is a term used to describe parent materials that: were transported by water gushing from glacial fronts. were laid down in the bottom of former glacial lakes. were transported by high winds during glacial periods are sorted by rapidly flowing melt waters contain a heterogeneous mixture of mineral debris dropped by receding glaciers.
contain a heterogeneous mixture of mineral debris dropped by receding glaciers.
Which of the following processes are most apt to encourage good soil aeration? 1) root respiration 2) organic matter decomposition 3) diffusion of oxygen from the soil to the atmosphere 4) creation of more macropores 5) reaction of oxygen with organic matter True or False Questions (Write T or F after each question.)
creation of more macropores
Loss of P to groundwater is likely to be most significant for which type of soil? 1) highly weathered tropical soils 2) silt loam soils formed in windblown loess 3) cultivated organic peat soils 4) sandy soils under pine forests (Spodosols) 5) calcareous soils
cultivated organic peat soils
Soil detritivores feed principally on ___. 1) smaller organisms 2) plant roots 3) larger, but defenseless animals 4) dead tissues 5) microorganisms
dead tissues
Urban development of land under natural vegetation or agriculture usually greatly _____ soil infiltration capacity and therefore greatly increases _______. 1) decreases stream bank erosion. 2) increases stream bank erosion. 3) decreases groundwater recharge. 4) increases .groundwater recharge.
decreases stream bank erosion.
Wetlands and forests growing along the banks of rivers remove much nitrogen from groundwater by the process of _________. 1) immobilization 2) nitrification 3) denitrification 4) ammonification 5) none of the above
denitrification
The bulk of gaseous interchange in soils takes place by _____. 1) mass flow 2) partial pressure of N2 3) diffusion 4) dissolution in water 5) respiration
diffusion
The expression, P - ET -SS estimates the ________ a watershed. 1) soil water contentof 2) discharge volumefrom 3) evaporation from 4) interception in
discharge volumefrom
Which of the following irrigation systems produces the most biomass per unit of water applied? 1) flood irrigation 2) furrow irrigation 3) drip irrigation 4) sprinkle irrigation 5) furrow-dike irrigation
drip irrigation
Where high-value crops or individual ornamental shrubs are to be grown and water is expensive, the most efficient type of irrigation to use would be ______. 1) center pivot 2) basin flooding 3) furrow 4) drip or trickle True or False Questions
drip or trickle True or False Questions
Assume you want to grow azaleas in a soil with a pH of 6.0. The application of which of the following would be most appropriate to make this soil suitable for this ornamental? 1) chicken manure 2) limestone 3) elemental sulfur 4) iron oxide 5) hydrated lime
elemental sulfur
Meso- and macrofauna contribute to organic matter decomposition primarily by ______. 1) enzymatic digestion of plant residues 2) enhancement of microbial activity 3) predation 4) synthesis of humus 5) none of the above
enhancement of microbial activity
The exchange complexes of strongly acid (pH 4.5) mineral soils are saturated mainly with _____. 1) exchangeable H+ ions 2) exchangeable Al3+ ions 3) exchangeable Al(OH2)+ ions 4) tightly bound H+ ions 5) tightly bound Al3+ ions
exchangeable Al3+ ions
Which of the silicate clays would likely have the highest level of potassium in the crystal structure? 1) kaolinite 2) chlorite 3) smectite 4) fine-grained mica 5) vermiculite
fine-grained mica
You are working with a soil colloid known to have a reasonably high potassium level, a cation exchange capacity of about 20 cmolc/kg 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? 1) vermiculite 2) smectite 3) kaolinite 4) humus 5) fine-grained mica
fine-grained mica
Which of the following organisms can commonly be seen with the unaided eye in organic matter-rich soils? 1) fungi 2) bacteria 3) Nematodes 4) actinomycetes 5) none of the above
fungi
Which of the following means of estimating soil water levels gives a direct measurement of the water content? 1) gypsum blocks 2) neutron scattering 3) gravimetric determinations 4) tensiometer 5) pressure membrane
gravimetric determinations
In which of the following "forms" of soil water are pesticides, excess plant nutrients and waste chemicals most apt to move through soils? 1) gravitational 2) unsaturated 3) available 4) hygroscopic 5) capillary
gravitational
Soils high in organic matter commonly hold more available water than comparable soils with lower organic matter levels. This is most likely due to what characteristics of the high O.M. soils 1) larger micro pore space 2) lower permanent wilting percentage 3) higher field capacity 4) higher capacity of the O.M. to hold water tightly 5) higher clay content
higher field capacity
The layers of contrasting material found when one digs a hole in the ground are called _______. pseudoliths regoliths pedons horizons soil structure
horizons
The opposite process from mineralization is _______. 1) immobilization 2) nitrification 3) denitrification 4) ammonification 5) none of the above
immobilization
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 _____. 1) well in advance of the plant's main period of nutrient uptake 2) evenly across the entire area to be fertilized and mixed thoroughly with the soil in the root zone 3) in narrow bands or localized concentrations 4) in combination with ground limestone 5) a combination of both B and D would be best
in narrow bands or localized concentrations
Increasing the organic matter content of a soil is likely to _____. have no effect on water holding capacity increase the soil's water holding capacity decrease the soil's water holding capacity
increase the soil's water holding capacity
Capillarity in soils _____. 1) involves both adhesion and cohesion 2) is enhanced by the symmetrical nature of the water molecule 3) is independent of the matric potential in soils 4) is not involved in the process of water uptake from soils 5) does not account for unsaturated water movement in soils
involves both adhesion and cohesion
You find that the CEC of a sandy loam soil at pH 5.0 is 8 cmolc/kg and at pH 8.2 it is 14 cmolc/kg. What is the most likely reason for this difference? 1) increase in the pH-dependent charges on 2:1 type silicate clays 2) removal of Al3+ ions from the exchange complex at higher pH. 3) ionization of carboxyl and phenolic groups to release H+ ions 4) removal of Al atoms from tetrahedral layers at low pH. 5) replacement of trivalent Al3+ ions with divalent Ca2+ ions at high pH.
ionization of carboxyl and phenolic groups to release H+ ions
Phosphorus availability in acid soils is constrained by the presence of significant quantities of reactive ______. 1) iron 2) calcium 3) magnesium 4) sulfur 5) boron.
iron
Which of the following silicate clays would be least apt to be formed from the mere alteration of primary minerals? 1) smectite 2) vermiculite 3) chlorite 4) fine-grained micas 5) iron or aluminum oxides
iron or aluminum oxides
Brown and red colors in subsurface horizons are caused by __ in the soil. 1) manganese 2) aluminum oxides 3) organic matter 4) clay 5) iron oxides
iron oxides
Which of the following human actions is most apt to result in a long term increase in soil pH? 1) application of NH4- containing fertilizers 2) application of farm manure 3) irrigation with high sodium salt-containing waters 4) emission of gases from automobiles 5) application of unlimed sewage sludge
irrigation with high sodium salt-containing waters
The negative charges associated with smectite clay crystals are due mostly to _____. 1) isomorphous substitution of Mg for Al in the octahedral sheet 2) substitution of Al for Mg in the tetrahedral sheet 3) high pH associated with the formation of the mineral 4) substitution of Si for Al in the tetrahedral sheet 5) OH groups on the external surface of the crystal
isomorphous substitution of Mg for Al in the octahedral sheet
Compared to gypsum, elemental sulfur is sometimes considered a more desirable fertilizer material because _____ 1) plants respond to sulfur more rapidly 2) it is less dependent on warm, moist conditions for availability 3) it contains more nutrient sulfur, kilogram for kilogram, than gypsum 4) it causes less soil acidity than gypsum 5) all of the above
it contains more nutrient sulfur, kilogram for kilogram, than gypsum
Land drainage is beneficial because _____. 1) it increases the alternate of expansion and contraction due to freezing and thawing of soils 2) it increases the water-to-air ratio in the soil pores 3) it slows down the rate of soil warming in the spring 4) it increases the depth of root penetration in the soil 5) it increases the availability of iron and manganese in acid soils
it increases the depth of root penetration in the soil
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? 1) chlorite 2) fine-grained mica 3) smectite 4) kaolinite 5) vermiculite
kaolinite
As biotite weathers in soils, which of the following would not likely develop by mere alteration of this mineral? 1) fine-grained mica 2) kaolinite 3) smectite D.chlorite E. vermiculite
kaolinite
Compared to the same soil used for cropland, a forested soil would be expected to lose _____ total P to streams draining the watershed. 1) less 2) about the same amount of 3) more
less
Using a textural triangle chart, it can be determined that a soil with 45% sand and 20% clay belongs to the ___textural class. 1) sandy loam 2) loamy sand 3) sandy clay loam 4) loam 5) sandy clay
loam
Dull gray colors are characterized by _____. 1) gray hues 2) low chromas 3) high color values 4) low color values 5) mixed hues
low chromas
Which of the following is not a characteristic of soil colloids? 1) very small size 2) high external surfaces 3) electronegative charges 4) ability to exchange ions with the soil solution 5) low water holding capacity
low water holding capacity
Practices that add organic matter and reduce tillage can be expected to most significantly increase the _____ in a soil. Correct Answer 1) macropores Incorrect Response 2) total porosity 3) bulk density 4) fineness of texture
macropores
An acid soil is known to contain toxic quantities of a certain plant nutrient. Which of these essential elements is it most likely to be? 1) nitrogen 2) manganese 3) phosphorus 4) molybdenum 5) boron
manganese
Residual parent materials are best described as __________. materials formed under organic residues. materials formed by weathering of rocks and minerals in place. materials transported from one location to another by water, ice or wind. materials more dominant in Iowa than in the Southern United States upland materials formed with relatively little chemical weathering.
materials formed by weathering of rocks and minerals in place.
Compared to upland soils, wetland soils would be characterized by an abundance of _____. 1) methane 2) CO2 3) NO3- 4) SO42- 5) Fe3+
methane
Which of the following groups of organisms are responsible for greatest amount of organic matter decomposition in soils? 1) macrofauna 2) microfauna 3) mesofauna 4) microflora 5) autotrophs
microflora
The process of ______ releases soluble nitrogen as the result of the breakdown of nitrogen-rich organic compounds. 1) nitrification 2) denitrification 3) symbiosis 4) volatilization 5) mineralization
mineralization
Soil A has a redox potential of 400 mV, soil B -200 mV. Of the two soils, Soil A is more apt to be characterized by an abundance of _____. 1) Fe2+ ions 2) Mn2+ ions 3) H+ ions 4) S2- ions 5) molecular oxygen
molecular oxygen
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 from 4.0 to 7.5, which of the following would you choose? 1) montmorillonite 2) kaolinite 3) fine-grained mica 4) humus 5) chlorite
montmorillonite
Compared to the bulk soil in which the earthworms live, earthworm casts contain ____. 1) less of most plant-available nutrients 2) more nitrogen but less of other plant-available nutrients 3) more of most plant-available nutrients 4) more sand and silt 5) less organic matter
more of most plant-available nutrients
Non-point source losses of which element are considered to be a serious water pollution problem because the resulting high concentration of the element in stream water is toxic to most fish. 1) potassium 2) phosphorus 3) both a and b 4) neither a nor b
neither a nor b
Which of the following is not a major factor in determining the soil aeration status? 1) redox potential 2) volume of macropores 3) nitrogen gas 4) carbon dioxide 5) oxygen
nitrogen gas
Which of the following will increase the evaporation (E) from the soil surface? 1) adding straw mulch to the soil surface 2) the use of no-till culture 3) stubble mulch farming 4) plastic mulch 5) none of the above
none of the above
The amount of P lost from agricultural soils by the process(s) of _____ is generally considerably greater than the corresponding losses of potassium. 1) leaching 2) harvest removal 3) gaseous evolution 4) both b and c are correct 5) none of the above are correct
none of the above are correct
Because of _______, soils developed in marine marshes can become extremely acid if drained for agriculture or used as topsoil. 1) oxidation of sulfates 2) reduction of sulfates 3) oxidation of sulfides 4) reduction of elemental sulfur 5) all of the above
oxidation of sulfides
The drainage of certain wetlands has resulted in extreme soil acidity. This is due primarily to which of the following processes that take place when the soil is drained? 1) oxidation of organic materials to produce organic acids 2) reduction of iron to low valent states that stimulate acidity 3) release of nitric acid due to oxidation of nitrogen compounds 4) high redox potential characteristic of aerated soils 5) oxidation of sulfur-bearing minerals that produces sulfuric acid
oxidation of sulfur-bearing minerals that produces sulfuric acid
In most soils, mineralization of soil organic matter is an important source of plant available ____. 1) potassium 2) phosphorus 3) both A and B 4) none of the above
phosphorus
Applied to agricultural crops, the term lodging refers to ________. 1) pre-mature fruit drop as a result of N deficiency 2) infestation with a high number of insect larvae lodged in the fruits or seeds 3) short, stubby plants starving for N or S 4) plants falling over, often as a result of too much N 5) plants losing their leaves because of a N imbalance
plants falling over, often as a result of too much N
Which of the following groups is not considered to include important primary consumers in the soil ecosystem? 1) detritivores 2) herbivores 3) fungi 4) saprophytes 5) predators
predators
Char is made up of _____. 1) living organisms and cells woven through wood ash 2) dead plant & animal tissues 3) identifiable biomolecules 4) pyrolized plant materials 5) all of the above
pyrolized plant materials
Mycorrhizae improve the nutrition of many plants by ______. Incorrect Response 1) transporting phosphorus through the soil to the plant root 2) fixing atmospheric phosphorus into forms readily used by plants 3) masking P-fixation sites on the surface of certain soil minerals Correct Answer 4) readily dissolving iron and aluminum phosphate compounds 5) making the root cell membrane more permeable to phosphate ions
readily dissolving iron and aluminum phosphate compounds
If you owned a dairy farm with poorly drained clay soils in a humid temperate region which of the following would be most satisfactory from the standpoint of soil aeration and temperature? 1) no-till system 2) conventional moldboard plow system 3) ridge-till system 4) heavy organic residues 5) heavy chemical fertilization
ridge-till system
A landscaping contractor wants to change the texture of a silt loam soil to meet the specifications for a loam. S/he would most likely do so by adding ______ to the soil and mixing it well. 1) humus 2) compost 3) clay 4) sand 5) either A or B
sand
Alluvial fans are usually characterized by ______ soils. sandy and gravelly clay textured poorly drained nearly level
sandy and gravelly
The most common form of on-site waste water treatment for homes not hooked up to sewer lines is the _______. 1) active composting method 2) septic tank and drain field 3) chemical "flush" system 4) electrical induction sterilization 5) soil enrichment process
septic tank and drain field
The percentages of which soil components represent the minimum information necessary in order to determine the textural class of a soil? 1) gravel and sand 2) silt and sand 3) clay and organic matter 4) clay, water and air 5) sand, silt and clay
silt and sand
Texture describes the ____ of particles in a soil. 1) sizes 2) colors 3) arrangement 4) mineralogical makeup 5) roughness
sizes
Soils rich in which type of clay would provide the most troublesome site on which to build a home? 1) Fe, Al oxides 2) kaolinite 3) fine-grained micas 4) chlorite 5) smectite
smectite
Which of the following pools contain the largest amount of the world's carbon? 1) soil 2) vegetation 3) atmosphere 4) animals
soil
The electronegative charge on 2:1 type silicate clays is due primarily to _____. 1) ionization of surface OH groups 2) substitution of one metallic atom for another in the crystal structure of the clay 3) extremely small size of the individual colloid particles 4) the effect of pH on the presence of H+ ions in the exchange complex 5) the preponderance of tetrahedral sheets compared to octahedral sheets
substitution of one metallic atom for another in the crystal structure of the clay
The principal form of sulfur taken up by plants is ____. 1) sulfate 2) sulfur esters 3) sulfides 4) elemental sulfur 5) gypsum
sulfate
An organism that subsists by eating predators would function as a(n) _____ in the soil ecosystem. 1) primary consumer 2) detritivore 3) tertiary consumer 4) decomposer 5) all of the above
tertiary consumer
The amount of different sizes of mineral particles in a soil defines the soil ________. structure pore space texture solution profile
texture
Mechanical weathering processes result in: the decomposition of primary minerals the hydrolysis of minerals through frost action the disintegration of rocks due to differential expansion of minerals the oxidation of iron and manganese compounds
the disintegration of rocks due to differential expansion of minerals
The swelling/shrinking tendency of some silicate clay minerals is due primarily to _____. 1) the presence of cations attracted by the negative charges on the internal surfaces 2) the movement of water molecules in and out of the interlayers of the crystal 3) varying thickness of the film of water covering the external surface of the particles 4) expansion in the width of the interlayers due to movement of larger ions such as K+ 5) the high Mg2+ contents in the octahedral layers
the movement of water molecules in and out of the interlayers of the crystal
Soil tilth refers to _____. 1) the bearing strength of a soil under a given downward force 2) the moisture content at which a soil is best suited for tillage 3) ratio of bulk density to particle density 4) the physical suitability of a soil for plant growth 5) micro-aggregates produced as a by-product of tillage True or False Questions
the physical suitability of a soil for plant growth
The likelihood of polluting groundwater with pesticides and plant nutrients is enhanced by _____. 1) the presence of macropores in the soil 2) light tillage of the upper centimeter or so of soil 3) the use of tillage to control weeds 4) the production of oats rather than wheat 5) conventional tillage as a choice compared with conservation tillage
the presence of macropores in the soil
The redox potential is a measure of _____. 1) molecular oxygen content 2) the tendency of a substance to accept or donate electrons 3) carbon dioxide content 4) the ferric ion content 5) the balance between hydrogen and hydroxyl ions in solution.
the tendency of a substance to accept or donate electrons
Which of the following would likely grow best on a soil with a pH of 6.0? 1) alfalfa Incorrect Response 2) sweet clover Correct Answer 3) tomatoes 4) blueberries 5) cranberries
tomatoes
In which of the following situations would you expect downward movement of soil water through the profile to be most rapid? 1) uniformly textured sandy loam profile 2) sandy loam in upper layers with a clay band underneath 3) sandy loam in upper layers with a layer of coarse gravel underneath 4) clay texture throughout the profile 5) silt loam in upper layers underlain by a sandy layer
uniformly textured sandy loam profile
Which of the following is not considered one of the five major factors influencing soil formation? native parent materials living organisms climate valence state topography
valence state
Ammonium fixation would be expected to be greatest in soils containing a lot of______. 1) Rhizobium bacteria 2) Frankia 3) vermiculite 4) iron oxides 5) both C and D
vermiculite
Which of the following trees would you expect to fare most poorly in a soil at pH 5.0? 1) loblolly pine 2) aspen 3) sumac 4) walnut 5) white spruce
walnut
Which of the following best characterizes the field capacity of a soil? 1) maximum capacity of a soil to hold water 2) water content of a soil with water potential of about -10 kPa 3) the total capillary water in a soil 4) a wetted soil prior to the removal of the gravitational water 5) soil with water potential of -1500 kPa
water content of a soil with water potential of about -10 kPa
In the early stages of plant nitrogen deficiency, the most obvious symptoms are _____. 1) yellowing of the youngest leaves 2) brown spots and tiny holes on the underside of most leaves 3) purpling of the youngest leaves 4) yellowish colors in the oldest leaves 5) brown edges on leaves scattered randomly all over the plant
yellowish colors in the oldest leaves
