SSC 200 Final Exam Crouse

Residual soil acidity is the active acidity remaining in the soil after limestone has been applied.

False

Roots of most plants have difficulty growing through soil if the bulk density is greater than 1.0 Mg/m3.

False

Slope length is generally of greater significance in determining erosion rate than is steepness of slope.

False

The property of cohesion in water stems from the attraction of water molecules for soil solids.

False

The rate of chemical weathering is affected very little by the downward movement of water, oxygen, and organic and inorganic acids flowing through the soil profile.

False

A soil developed in transported parent materials will likely have properties related to the properties of the rock below the C horizon.

False

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

False

A, B, C, and E horizons can be found in any true soil.

False

All but a few nematodes are pests, attacking either economic or wild plants.

False

Although subsoil is more difficult to obtain, it is generally equally as good as topsoil for landscaping purposes.

False

Humus is an important nutrient, essential for healthy plants.

False

In general, alluvium in not good for agriculture.

False

Iron and manganese are commonly deficient in very acid soils.

False

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

False

Most, if not all, of the nutrient supply stored in a fertile soil is in forms readily available to plants.

False

Mulches and crop residues affect soil water by increasing evapotranspiration.

False

Natural soils (as opposed to modern farm soils) can recycle organic compounds, but not inorganic elements.

False

Nitrogen use efficiency is consistent among all plants and averages about 95%.

False

Polysaccharides produced by soil microbes and similar synthetic polymers applied to soils are largely responsible for the crusts that form when rain follows tillage.

False

Removing all the straw with the harvest of paddy rice would increase the amount of methane produced by the paddy soil microorganisms.

False

Residual parent materials have generally been subjected to weathering for a longer period of time than have lacustrine or alluvial parent materials.

True

Sapric and fibric are terms used to describe peat parent materials.

True

Soil air usually has a higher carbon dioxide content than the air in the atmosphere.

True

Soil and crop management generally has a greater influence on evaporation from the soil surface (E) than on transpiration (T) from leaf surfaces.

True

Soil chemistry can affect dispersion, which is a soil physical condition where each soil particle behaves as an individual and aggregates do not form.

True

Soil consistence changes with changes in soil water content.

True

Soil microorganisms often compete with higher plants for mineral nutrients, such as nitrogen.

True

Soil phosphorus is associated with eutrophication of lakes.

True

Some nitrogen-containing fertilizers are significant sources of soil acidity in cultivated soils.

True

The T values are the maximum losses of soil by erosion that can be tolerated without a reduction in the soil's long term productivity.

True

The amount of exchangeable acidity is much smaller than the residual acidity.

True

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

True

Plant roots are an important source of carbon for many soil organisms which are beneficial to plants.

True

Plants can be grown without any soil.

True

Practices that tend to increase the amount of organic matter in soils would be expected to reduce the global greenhouse effect.

True

Which type of soil structure is typically found in surface soil (A horizons)?

granular

Some soil colloids exhibit positive charges under highly acid conditions. To what are these charges likely due?

protonation of some hydroxy groups by excess H+ ions

A soil at field capacity has what percent water in the macropores?

0%

Which formula best describes soil porosity?

1 - (bulk density/particle density)

The octahedron building unit of a clay crystal contains _____ atoms.

1 aluminum and 6 oxygen

A pure clay crystal of kaolinite contains one octahedral layer and one tetrahedral layer. Which of these descriptions best describes the individual tetrahedrons that form the tetrahedral layer:

1 silicon and 4 oxygens

A sandy clay can contain a maximum range of_____.

45% to 65% sand

In a load of 10 cubic meters of topsoil, approximately how many cubic meters of the volume would be solid material?

5

In what range of soil pH is phosphorus generally most available to plants?

5.5 to 7.0

In a typical mineral soil in optimal condition for plant growth, approximately what percentage of the pore space would be filled with water and what percentage filled with air?

50% water and 50% air

The clay fraction is represented by particles less than _____ in size.

< 0.002 mm

"Subsoil" is generally equivalent to which soil horizon?

A

"Topsoil" is generally equivalent to which soil horizon?

A

In a given soil, the horizon with the highest organic matter content is generally the _____ horizon.

A

Which of the following locations in the United States would have the highest evaporation (E) from the soil surface in July?

A furrow-irrigated cotton field in Arizona

Organic matter accumulation is most pronounced in the _____.

A horizon

The water in the soil typically differs from pure water because the soil water ________.

ALL a. contains mineral nutrients b. contains organic compounds c. is restrained in its flow by attraction to particle surfaces

Which of the following statements are true concerning cohesion and adhesion?

Adhesion is the force that initiates capillary rise in micropores.

Which of the following statements is correct? a. Calcium carbonate accumulation is more prominent in humid than in arid regions Incorrect b. Soils on hillsides tend to be deeper than those on level lands c. Soils formed under grassland vegetation have thinner A horizons than those formed under forest vegetation d. Alluvial parent materials have been subject to weathering for shorter periods of time than residual parent materials nearby

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

Which type of parent material would you find as the result of water transportation?

Alluvium

What ion is probably most influential in causing very acid soil pH values?

Aluminum

Which ion hydrolyzes water molecules and causes some very low soil pH values. _____.

Aluminum

Which of these elements would produce a toxic environment for plants in acid soils?

Aluminum

Which of these ions would be held more tightly than calcium within the cation exchange complex?

Aluminum

Which of these processes represent a loss of nitrogen from the soil?

Ammonia Volatilzation

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

Among the soils of which order would you most likely find the highest buffering capacities?

The _____ horizon not found in the profile of entisols.

B

Which horizon is lacking in Entisols?

B

In which of the following horizons has the process of illuviation most likely occurred?

B horizon

What property would be most useful in determining how fast a soil will exchange oxygen for carbon dioxide in the plant root zone?

Bulk density

Which ion is most tightly bound to colloids?

Calcium

If soil pH was observed to gradually increase and then gradually decrease over a 4-6 year period, what chemical(s) had probably been added to the soil at the start of this period:

Calcium carbonate

Which ion is not attracted to most soil colloids?

Chloride

These particles have colloidal properties such as the ability to stay suspended indefinitely.

Clay

USDA considers this particle to be smaller than .002mm.

Clay

Which of the following is not one of the soil orders?

Crysol

Which soil profile horizon will be formed as a result of intense eluviation processes and be typical of Spodosols?

E

Which soil horizon is the zone of maximum eluviation?

E Horizon

Organic matter is more resistant to decay than iron oxides.

Fakse

A 1:1,000,000 soil survey has a larger scale than a 1:5,000 soil survey.

False

Histosols generally have lower organic matter contents than Mollisols.

False

Application of phosphorus fertilizer usually makes plants more susceptible to diseases.

False

Aridisols generally contain more organic matter than Mollisols.

False

As decomposition of added organic material proceeds, the C/N ratio in the remaining undecomposed material steadily increases.

False

As food production is increased in developing countries around the world, micronutrient deficiencies are likely to become less of a problem than they are today.

False

At the soil moisture status "air dry," water can easily be extracted by plants.

False

Conventional tillage changes the porespace distribution of soil used for agricultural production compared to a similar soil under native vegetation. Generally, following tillage, the volume of macropores is greater in the agricultural soil. This is a permanent change in macropore volume that remains long after tillage has ended.

False

Examples genetic horizons include kandic, spodic, ochric, mollic and oxic.

False

Except for some kinds of foods, modern industry has made human dependence on soils a thing of the past.

False

For most soils, plowing every year improves soil tilth in the long run.

False

Forests in decline because of acid deposition can often be brought back to high productivity with just a few applications of nitrogen fertilizer.

False

Forests would typically have more organic accumulation than grasslands.

False

Glacial till is laid down by melt waters gushing out from the front of glaciers.

False

Soils can recycle organic compounds, but not inorganic elements.

False

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

False

Sprinkle irrigation is generally more efficient in the use of water than drip irrigation, especially for high valued crops.

False

Subsoil is typically equivalent to the O horizon.

False

Subsoiling is a primitive deep tillage technique that results in extremely high subsoil bulk density.

False

The broadest category of classification in Soil Taxonomy specifies 12 soil orders, 4 of which are for primarily comprised of organic soils

False

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

The dark brown and black humus found in many soils does not mix well with clay minerals so there is very little contact between these two soil components.

False

The deeper that they are placed in the soil, the more rapidly organic compounds such as pesticides are decomposed by the soil microflora.

False

The lower the cation exchange capacity of a soil, the higher is its buffer capacity.

False

The tenacity with which water is held in soils is directly related to the soil moisture content, the higher the moisture level the greater the attraction of the water to the soil.

False

The topmost horizon in most humid region forest soils is the A horizon.

False

Tropical forests protect the soil from excessive weathering.

False

Vapor loss from a south-facing slope in Australia would likely be higher than from a north-facing slope.

False

Where organic matter constitutes only 1 or 2 percent of the soil by weight, it has only negligible influence on soil properties.

False

With the exception of vermiculite and associated silicate clays which tend to have no-charge, most soil colloids are predominately electropositive.

False

The cation exchange capacity of humus is not affected by soil pH.

False, the CEC of humus is entirely dependent on pH

In explaining erosion processes to a friend, which of the following would you say about accelerated erosion?

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

Select the appropriate soil order: Permanently frozen soil.

Gelisols

Which type of structure is never found in subsoils?

Granular

Soils with thick horizons consisting mainly (> 30% by weight) of organic matter and that form in topographic depressions or low-lying places usually belong to the order ________.

Histosols

Which of the following set of terms and matching horizon designation describe the zone of maximum clay accumulation in a soil formed in a humid region?

Illuvial, Bt

Which process describes the conversion of plant-available form to an unavailable nitrogen form?

Immobilization

During the reaction whereby limestone changes the pH of a soil, what is the fate of the acid H+ that makes it unable to affect soil acidity?

It becomes part of the water molecule.

Which of these properties about a tillage pan is false?

It is permanent and cannot be corrected with deep tillage.

Which type of parent material would you find as the result of wind transportation?

Loess

Gravitation water is found in the _____

Macropores

As a soil dries, plants must expend more and more energy to remove any remaining water. What forces is this energy expenditure overcoming in the soil?

Matric potential and osmotic potential

Plant available water is stored in _____.

Mesopores

Hygroscopic water is stored in _____.

Micropores

Which major nutrient form is involved in reactions that acidify soil?

NH4+

The amount of P lost from agricultural soils by the process(s) of ________ is generally considerably greater than the corresponding losses of potassium.

NONE OF THE ABOVE a. leaching b. gaseous evolution c. harvest removal d. both B and C are correct

Over the length of a growing season, which nutrient would move furthest from a fertilizer pellet placed in the root zone?

Nitrogen

Nitrification is a two-step process with nitrite (NO2-) being formed in step one and then nitrite being oxidized to nitrate (NO3-) in step 2. Which bacteria are responsible for step 1?

Nitrosomonas

Which horizon would always be present in a Histosol?

O

Organic matter accumulation is most pronounced in the ________.

O horizon

Which one soil condition is most instrumental in fostering the process of denitrification?

Periods of excessive wetness

Select the appropriate structure: Vertical orientation. Can be found in the subsoils in humid regions. Lacks the salt "cap" typical of a similarly shaped unit of structure. Not ideal for plant growth.

Prismatic

What feature would best tell a soil's "age"?

Profile differentiation

Which is not included in the epipedon?

R horizon

Which of the following statements is true?

Rill erosion channels can be removed by ordinary cultivation.

The total surface area is greatest in which textural class:

Sandy clay

Which cation does not promote flocculation in the soil?

Sodium

Which of the following is not a factor affecting CEC?

Soil structure

All of the following are essential elements needed for a plant to complete its life cycle. Which one is considered a Secondary Macronutrient?

Sulfur

Soil age can best be determined by which factor?

The presence or absence of specific horizons

Which of the following statements is not correct? a. Where dense forests are found, soil profiles have prominent O horizons. b. Grasslands are found in semi-arid and sub-humid areas. Incorrect c. The type of native vegetation is controlled primarily by climate. d. Tropical forests protect the soil from excessive weathering. e. Coniferous forests are found mostly in cool humid areas.

Tropical forests protect the soil from excessive weathering.

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

True

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

True

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

A soil developed in residual parent materials will likely have properties related to the properties of the rock below the C horizon.

True

Andisols are found mostly near recently active volcanoes.

True

Compared to conventional tillage systems, most conservation tillage systems rely more heavily on herbicides to control weeds.

True

Conservation tillage has generally positive effects on soil physical properties.

True

Eluviation of clay, iron, and other materials is the principal process responsible for the formation of an E horizon.

True

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

True

Fungal hyphae play an important role in stabilizing surface soil aggregates.

True

Humus has a much higher cation adsorption capacity than clay.

True

Igneous rocks are formed when molten magma cools and solidifies.

True

In humid regions most rainwater that soaks into the soil and is not used by plants eventually flows into rivers and streams.

True

In order for nitrate to form from soil organic matter, Nitrosomonas and Nitrobacter must both be present in the soil.

True

In the United States, losses of soil due to wind and water erosion decreased by nearly 40% between 1982 and 2003.

True

In the south eastern United States, well aerated soils can easily be identified by the presence of bright red colors in the subsoil.

True

Marine sediments are typical parent materials in coastal plain areas.

True

Mineralization of soil organic matter results in the addition of inorganic nutrient ions to the soil solution.

True

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

True

Most irrigation systems are very inefficient with less than half the water that is taken from streams ever reaching the plants.

True

Most nitrogen leaching to groundwater is in the form of nitrate.

True

Most of the water flowing in rivers passed through a soil profile or over soil surfaces before reaching the river.

True

Most of the water in our rivers and lakes has come in contact with and has been affected by soils.

True

Of all the groups of soil organisms, bacteria have the most diverse metabolic capabilities.

True

The broadest category of classification in Soil Taxonomy specifies 12 soil orders. One order describes frozen soils. One order describes organic soils. The remaining 10 orders describe mineral soils.

True

The drainage class of a soil (the degree to which the soil becomes water-saturated during the year) can be judged by the presence and location of gley in the soil profile.

True

The drainage class of a soil (the degree to which the soil becomes water-saturated during the year) can be judged by the presence and location of gray colors in the soil profile.

True

The effect of soil organic matter on the amount of water available to plants is due to organic matter influence on total soil porosity as well as to the water-supplying power of the soil organic matter.

True

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

True

The mineral particles in soil consist of sand, silt, and clay.

True

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

Tillage when the soil is too wet is likely to increase the soil bulk density.

True

Total soil water potential is a function of gravitational potential, osmotic potential and matric potential.

True

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

True

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

Soils in which of the following soil suborders would most likely have a prominent E horizon under the A horizon?

Udalfs

Select the appropriate epipedon: A thick, dark, colored mineral horizon (generally > 25 cm) with a base saturation less than 50%.

Umbric

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?

Ustox

The agent responsible for depositing lacustrine parent material is

Water

The agent responsible for transporting of alluvial deposits is

Water

Ammonia losses are likely to be greatest if a nitrogen source is placed about 10 cm deep in ________.

a calcareous sandy loam soil

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 soil with a bulk density equal to 0.35 Mg/m3 is most likely what type of soil?

a peat soil

Organic parent materials accumulate under which of the following conditions?

a. Restricted aeration b. Cold & damp climates c. Water-logged soil conditions

Modern nutrient management is designed to ________.

a. cost-effectively produce quality plants b. conserve nutrient resources c. protect or improve environmental quality d. protect or improve soil quality

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?

a. destruction of natural forests b. burning of fossil fuels c. loss of soil organic matter

Which of the following practices is(are) useful in stabilizing surface soil structure?

a. minimizing tillage b. growing grass sod c. use of organic mulches d. use of cover crops

Plants obtain nitrogen from the soil by taking up ________.

a. soluble anions b. soluble organic compounds c. soluble cations

Because of their greater surface area per unit of soil mass, silt loams soils generally have a greater capacity than loamy sand soils to ________.

a. support bacterial growth b. release nutrients by mineral weathering c. adsorb gases d. adsorb water

Residual soil acidity is a measure of the _____.

aluminum and hydrogen bound to the charge of the clay and humus surfaces

An example of isomorphic substituion would be the substitution of _____ for _____.

aluminum, silicon

Volatilization is the process by which _____ is lost from the surface of a soil.

ammonia

Field capacity is the _____.

amount of water in a typical forest soil the day after a saturating rain

Symbiotic nitrogen fixation involves _____.

an invasion of plant roots by bacteria

The presence of rocks such as shale and sandstone indicate the existence of ________.

ancient seas

Organisms which use carbon dioxide or carbonates for their carbon source and either sunlight or inorganic chemicals for their energy source are called ________.

autotrophs

Methemoglobinemia is principally a potential threat to ________.

babies drinking water high in nitrate

Compaction reduces all of these properties, except _____.

bulk density

Porosity tends to increase as _____.

bulk density decreases

The quality of a liming material determined by its _____.

calcium carbonate equivalency

Nearly all organic compounds from which living beings are made have as their backbone, chains or rings of ________ atoms

carbon

A sticky, putty-like feel indicates a high percentage of which soil separate?

clay

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.

clay

Which soil textural class would have the lowest bulk density?

clay

In _____ textured soils, nutrient leaching is a concern because of low in cation exchange capacities:

coarse

The mixed angular gravel, rock, and soil found at the foot of a slope is typical of what type of parent material?

colluvial

Which type of structure is typically found in sodium-rich sub-surface horizons?

columnar

Loose, hard, plastic and firm are terms that describe _____.

consistence

One would expect well drained soils to have the highest organic matter contents where the climate is ________.

cool and humid

Grass vegetation affects soil development in ways that will leave the soil _____ than soils under forest vegetation.

darker and less acid

Detritus consists of ________.

dead tissues and wastes

Sodic soils generally have a poor physical condition. To what is this most likely due?

dispersal of the Na saturated soil colloids

Soil macropores _____.

drain due to the force of gravity

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 ________.

drip or trickle

Which of the following statements is correct? a. Soils on hillsides tend to be deeper than those on level lands. b. Limestone parent materials enhance the process of acidification. c. Calcium carbonate accumulation is more prominent in humid than in arid regions. d. Nutrient cycling in forested areas contributes little to soil formation. e. Lacustrine parent materials have been subject to weathering for shorter periods of time than residual parent materials nearby.

e. Lacustrine parent materials have been subject to weathering for shorter periods of time than residual parent materials nearby.

Compared to silt, clay-sized soil particles are characterized by ________.

greater attraction for water

Select the appropriate subordinate horizon designation: Illuvial accumulation of organic matter.

h

Soils high in organic matter commonly hold more plant-available water than comparable soils with lower organic matter levels. This is most likely due to what characteristics of the high O.M. soils?

higher field capacity

Soils with a predominance of _____ colloids will require the largest amount of limestone to change soil pH from 5.5. to the optimum level.

humus

A soil testing lab reports a soil pH of 6.1. From that value you can directly calculate the _____.

hydrogen ions in the soil solution

The opposite process from mineralization is _____.

immobilization

Increasing the organic matter content of a soil is likely to ________.

increase the soil's water holding capacity

In particle size analysis by sedimentation, Stoke's Law predicts the velocity a particle falls through the suspension _____.

increases as the particle size increases

The element most often involved in oxidation reactions as minerals weather is ________.

iron

Poor plant growth in a well-drained irrigated soil in an arid region (pH=8.0) is most likely due to ________.

iron deficiency

Which of the following silicate clays would be least apt to be formed from the mere alteration of primary minerals?

iron or aluminum oxides

Land drainage is beneficial because ________.

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?

kaolinite

Perforation placement is usually used to fertilize ________.

landscape trees

Dull gray colors are characterized by ________.

low chromas

Carbon dioxide evolution from microbes and plants into the soil solution will _____ soil pH.

lower

In humid regions, soils are likely to have a pH _____ those found in semi-arid soils.

lower than

Compacting a soil increases all of the following, except

macroporosity

The attraction of water to the soil solids, responsible for capillary flow, is called _____.

matric potential

Which of the following groups of organisms are responsible for greatest amount of organic matter decomposition in soils?

microflora

The process of ________ releases soluble nitrogen as the result of the breakdown of nitrogen-rich organic compounds.

mineralization

A 2:1 clay is more active in soil than sand because the clay has _____.

negative charge

Which of the following is not a major factor in determining the soil aeration status?

nitrogen gas

If you want to maximize the quantity of vegetative cover on soil which of the following tillage practices would you use?

no-tillage

The great majority of nitrogen (95 to 98%) in soils can be found in the form of _____.

organic compounds

A soil has been managed using a no-till system for 10 years following many years of conventional tillage operations. Which of the following changes in surface soil properties would you expect due to the no-till management system?

organic matter content would increase

Which of the following subsurface diagnostic horizons would you expect to find in a highly weathered soil of the humid tropics?

oxic

Depostion and mineralization of organic materials in soil is not a significant contributor of the _____ used by plants?

oxygen

Select the appropriate subordinate horizon designation: A disturbance of the surface layer by mechanical means, pasturing, or similar uses.

p

The transformation of gneiss into smaller mica, quartz, and feldspar pieces is an example of ________.

physical weathering

Continuous cultivation and soil compaction tend to reduce the amount of _____ in the soil.

porespace

In recent years, a soil test for nitrogen has been developed and widely used in humid regions in predicting how much nitrogen will need to be applied to supplement natural mineralization in the soil. This test is called the ________.

pre-sidedress nitrate test (PSNT)

Within the technical capabilities of the particular lab, most soil test results can be best interpreted as indicating the ________.

probability (likelihood) that nutrient application will improve plant growth

The additions of organic matter to compacted clay will _____.

promote the formation of stable structure

The use of sedimentation to separate sand, silt, and clay depends upon the fact that smaller particles _____.

settle more slowly

The percentages of which soil components represent the minimum information necessary in order to determine the textural class of a soil?

silt and sand

Texture describes the _____ of particles in a soil.

sizes

Soils rich in which type of clay would provide the most troublesome site on which to build a home?

smectite

Wind erosion is generally not affected by ________.

soil pH

Most (usually 80% or more) of soil potassium and calcium can be found in the form of ________.

structural components of minerals

Select the appropriate subordinate horizon designation: Accumulation of silicate clay.

t

Exfoliation is caused by changes in _____.

temperature

The likelihood of polluting groundwater with pesticides and plant nutrients is enhanced by _____.

the presence of macropores in the soil

The likelihood of polluting groundwater with pesticides and plant nutrients is enhanced by ________.

the presence of macropores in the soil

A soil profile consists of ________.

the set of layers seen in a vertical cross Section of a soil

If you dug a deep hole in your back yard and water started to seep into the hole it would fill the hole up to ________.

the water table

A productive, heterogeneous deposit associated with glacial activity forms a parent material known as _____.

till

Glacial till soils are unique from other parent materials largely due to their

varied mixture of minerals

Select the appropriate subordinate horizon: Weak development of soil color or soil structure.

w

Which of the following best characterizes the field capacity of a soil?

water content of a soil 24 hours after a saturating rain

Hydrophobic soils are so named because the soil particles are coated with _____.

water repellent substances