SCSC 301 EXAM 1

What actions/characteristics are contributed to flocculation?

- *absorbed cation (Ca & Mg)* > promotes flocculation and aggregate formation > soil is friable and easily tilled > water penetrates easily > soil does not puddle when wet - *Absorbed cation (Na)* > promotes dispersion soil is difficult to till > soil dries into hard clods and is nearly impervious to water > soil puddles when wet - *wetting/drying* - *roots/animals* - *decaying organic matter/microbes* - *Physical activités* > freezing/thawing > heat (expand)/cool (contract) - *human management*

What are the 6 classes of minerals found in soils?

- Silicates - Oxides - Carbonates - Phosphates - Sulfates - Halides

What are the five shapes soil can form into?

- Spheroidal = granular (porous) and crumb (very porous) > horizon A > subject to wide and rapid change - Blocky = angular and sub angular > horizon b > occurs with clay, sub angular has less clay - Prism-like = columnar (rounded tops) and prismatic (flat, angular tops) > b horizon > columnar = Na on clays > prismatic = often parts of blocky - Platy > E & A horizons > inherited from parent material, caused by compaction - Structureless (massive, single grain)

What are the *macronutrients* vital for plant growth? {remember, MACROnutrients comprise >0.1%} hint: 3 nonmetallic and 3 metallic elements are listed

- calcium - magnesium - nitrogen - potassium - nitrogen - phosphorus - sulfur

What are the 3 soluble minerals?

- carbonates - halides - sulfates

What are the factors affecting soil aggregation?

- cation types (Ca yes, Na no) - natural causes of soil movement > wetting/drying > freezing/thawing > expanding (heat)/contract (cool) - organisms > plants, microbes, animals > humans - substances that cement or stabilize aggregates > microbial gums > iron oxides > carbon > clay

What does bulk density mean for soil?

- compaction - suitability for plant growth - suitability for building - assess how much soil and pore space you have relationship: - lower BD, lower weight, more pore space - higher BD, higher weight, less pore space

How does the soil modify the atmosphere?

- exchanges gases - absorbs O2 and CH4 - releases CO2, N2O - evaporation from soil major source of water vapor - soil dust

What are the 4 insoluble minerals?

- hematite - goethite - gibbsite - apatite

What are the *micronutrients* vital for plant growth? {remember, micronutrients comprise <0.1%} hint: 2 metallic and 2 nonmetallic elements are listed

- iron - copper - manganese - nickel - zinc - boron - chlorine - molybdenum *

Where can soil water be found?

- located in the pore space of soil > chemical attraction + physical particle arrangement = flow

Soil organic matter characteristics:

- microbial decomposition (respiration) convert soil organic matter to CO2 - soil organic matter bind mineral particles into granular soil structure that are facilitated by microbial and plant exudates

What actions/characteristics are contributed to cementation?

- microbial exudates - iron oxides - organic c - clay

How does soil aid in recycling raw materials?

- reuse of nutrients, plants and animals - reduce biomass by DECOMPOSITION - releases CO2 and nutrients - production of soil organic matter

What are the 3 soil solid characteristics that make up mineral particles?

- soil minerals - soil texture - soil structure

In what ways to soil provide habitat for organisms?

- spatially and chemically diverse, creates many different habitats - pore spaces > O2 rich > O2 poor (anoxic) > temperature, pH varies

In what ways can soil be used as a building medium?

- used to build structures - different soils are used to build structures - not all soils are terra firma - soils have different properties > stability > compressibility > strength (bearing & shear)

What are the corresponding colors with the associated soils? __1__ colored soils come from organic matter. __2__ colored soils come from iron and aluminum oxides. __3__ colored soils come from silicates and salts.

1 --- BLACK 2 --- RED 3 --- WHITE

What are the *6 soil ecosystem functions and services*? hint: (an acronym) MMURRP

1. Medium for plant growth 2. Modify atmosphere 3. Used for building and engineering 4. Regulate water supplies 5. Recycle raw materials 6. Provides habitats for organisms

What are the 4 arguments for why soil is important?

1. Provisions = provide water, food, medicines and lumber 2. Regulators = purify water, decompose wastes, control pests, modify atmosphere gases 3. Support = helps with nutrient cycling, seed dispersal, primary biomass production 4. Cultural Values = provides spiritual uplift, archeological preservation and outdoor recreation

What characteristics constitute soil as a medium for plant growth?

1. physical support = anchors plant roots 2. water = holds water necessary for photosynthesis 3. air = provides ventilation (CO2 <-> O2 exchange) 4. moderates temperature = insulates roots and organisms 5. protection from toxins = detoxification, microbial 6. provide nutrients = macro and micronutrients

What characteristics constitute soil as a regulator for water supplies? In other words, how does soil help regulate the water supply?

1. water (precipitation) runs over or through soils 2. water binds to solids in soil - stores water 3. purification via physical, biological and chemical processes

Identify the Value, Hue and Chroma of soil color __A__ __B__/__C__

A = hue B = value C = chroma

Which term is best described by the definition below? " _____ parent material is carried by gravity" A. Colluvial B. Residual C. Alluvial D. Subluvial

A. Colluvial - poorly sorted rock fragments - Talus = rock fragment slope - PM coarse and stony - Physical weathering dominated parent material - packing voids mean fast drainage - unstable

"aggregation and arrangement of particles" is the definition for: A. Structure B. Texture C. Porosity

A. Structure *how the particles are aggregated* - dynamic property that can be changed by management

"the amount of volume that will be reduced by a given force" is the definition for: A. compressibility B. compaction C. expansion D. strength

A. compressibility

Halite (NaCl) and Sylvite (KCl) are two minerals found in the ___ mineral class. A. halides B. sulfate C. phosphate D. oxides

A. halides ****very soluble****

Hematite, Goethite and Gibbsite make up the ____ minerals class. A. oxides B. silicates C. sulfates D. halides

A. oxides all three are very insoluble

Temperature and effective moisture interaction control the depth of weathering in the: A. regolith B. solum C. horizon D. bedrock

A. regolith SOIL DEPTH DOES NOT EQUAL REGOLITH DEPTH

_____ is the proportion of particle sizes A. soil texture B. soil structure C. soil formation D. soil triangle

A. soil *texture* texture is important for many soil properties

The probable sequence of dominance aggregate shapes from the surface down in a soil having A, B and C horizons would be: a. sub angular blocky, angular blocky, massive b. sub angular blocky, massive, angular blocky c. masive, sub angular, angular

A. sub angular, angular, massive

What is the soil that best describes these characteristics? _______ > most dynamic layer > darker (more organic matter) > more biological activity > less compacted, more pores > less clay A. subsoil B. topsoil C. surface soil

B&C topsoil is surface soil.

Which term is best described by the definition: Abandoned burrows filled with soil from another horizon. A. Topography B. Crotovinas C. Catena D. Colluvium

B. Crotovinas this is usually achieved by burrowing animals

Which term is best described by the definition below? " _____ parent material develops in place from underlying rock" A. Colluvial B. Residual C. Alluvial D. Subluvial

B. Residual - cooler, drier climates, color and chemical composition resemble the rock - warm and humid climates result in leaching, oxidized parent materials (red and yellow from oxidized compounds)

What term is best described in the following definition? When organic acids complex or chelate many metal cations and remove them from the mineral A. redox reactions B. complexation C. dissolution D. hydrolysis

B. complexation - chemical weathering characteristic

_____ are inorganic material derived from rocks A. matter B. minerals C. soil D. nutrients

B. minerals

A typical moist surface soil contains approximately 1-5% volume of A. mineral matter B. organic matter C. air D. oxygen E. secondary minerals

B. organic matter

The space between the solids can be summed up as A. porosity B. pore space C. volume D. mass

B. pore space ***related to bulk density and particle density*** - % pore space is the volume of pores compared to bulk volume

Consistence can be defined as A. capacity to withstand stresses without giving way by rupturing or deformation B. resistance to mechanical stress or manipulations at various moisture contents C. making soil more dense by removing air space

B. resistance to mechanical stress or manipulations at various moisture contents

Quartz, Feldspar, Amphiboles, Pyroxenes and Micas minerals make up the ____ mineral class. A. oxides B. silicates C. sulfates D. halides

B. silicates All but quartz form clays

____ is the arrangement of particles into aggregates A. soil texture B. soil structure C. soil formation D. soil

B. soil *structure*

What is *Bulk Density*?

BD = mass per volume of dry solids + pore space - soils (most) = 1..0 - 2.0 g/cm3 - optimal BD < 1.6g/cm3 (good for plant growth) more pore space, lower bulk density clay has lowest bulk density due to micropore space within aggregates; sand doesn't aggregate, only macropores

Which 2 elements compose the *pore space*What are the in soil? A. Carbon and Oxygen B. Iron and Salt C. Water and Air D. Minerals and Organic matter

C. Water and Air

"water contents where the soil properties change fro solid like to plastic like to liquid like" is the definition for: A. expansion B. strength C. atterberg limits D. compaction

C. atterberg limits

M(solids) / [V(solids) + V(pores)] is the equation for: A. porosity density B. particle density C. bulk density D. stokes law

C. bulk density

Smaller particles that can only be seen via electron microscope are called A. micronutrients B. aggregates C. colloids D. minerals

C. colloids *clay and humus* - most chemically and physically active part of soil because they exhibit electromagnetic charges that attract pos/neg ions and h2o

Strong, moderate, weak and structureless are the words that could be used to describe the _____ of the soil. A. shape B. size C. grade D. anatomy

C. grade *grade is another word for stability*

Aggregates can be defined as A. amount of force needed to crush a clod B. how well soil can shrink/swell C. group of primary soil particles that cohere to one another

C. group of primary soil particles that cohere to one another

Even though calcite is considered the soluble in humid environments, it can resist weathering in arid grasslands due to: A. stress cracks and high temperature-induced weathering B. strong redox reactions due to oxic conditions C. low rates of dissolution and acid dissolution D. increased chelation *from quiz #4*

C. low rates of dissolution and acid dissolution

Apatite belongs to the _____ mineral class. A. oxide B. sulfate C. phosphate D. halides

C. phosphates apatite is very insoluble

____ describes the unconsolidated debris overlying the lithosphere, composed of the O, A, E and B horizons. A. parent material B. solum C. regolith D. soil

C. regolith regolith is altered by physical, chemical and biological weathering and decay, formation of new minerals and Organic matter that can turn into soil.

____ is a dynamic natural body having properties derived from the combined effects of climate and biota, modified by topography acting on parent materiel over periods of time. A. horizons B. solum C. soil D. regolith

C. soil REMEMBER THE 5 SOIL FORMING FACTORS

_____ is compromised of carbonaceous substances that include compounds produced by current & past metabolisms of soil and contain living & dead biomass. A. horizons B. soil C. soil organic matter D. biota

C. soil organic matter

____ is the vertical section showing the different layers of soil, extending to the parent material. A. soil pit B. horizons C. soil profile D. solum

C. soil profile soil pits are used to identify and study soils, often used by pedologists for soil taxonomy.

"capacity to withstand stress without giving way by rupturing or deformation" is the definition for: A. consistence B. compaction C. soil strength D. expansion

C. soil strength

What term is best described by the following definition? "Relates to the physical condition of the soil in relation to plant growth" A. drainage B. aeration C. soil tilth D. stability

C. soil tilth

What is the *name of the soil* that make up the O, A, E and B horizons, right above C horizon? A. parent material B. regolith C. solum D. soil

C. solum Solum includes the O, A, E and B horizons but exclude the C horizon. The inclusion of the C horizon make up the regolith.

"size distribution of sand, silt, and clay" is the definition for: A. Bulk density B. Structure C. Texture

C. texture inherent property that does not change over our lifetime

____ weathering is the decomposition of rocks affiliated by hydration/hydrolysis, acid reactions, chemical complexation and oxidation/reduction.

CHEMICAL

Between sand, silt and clay, which is the smallest particle that has high affinity for water, nutrients and each other, tends to aggregate and can act as a colloid?

CLAY

Which of the 5 soil forming factors are best described by the following: - acts on parent material by the nature and intensity of weathering - influences biota

CLIMATE - increases in temperature can speed up biological weathering - defined by effective precipitation

Which two minerals make up the carbonate mineral class?

Calcite, CaCO3 = soluble in humid climates Dolomite, CaMg(CO3)2 = somewhat soluble in arid climates

What are the 5 soil forming factors?

Climate Biota Topography (Relief) Parent Material Time

Given the soil forming factors, what are the corresponding sequences? Climate Biota Topography Parent Material Time

Climate = Climosequence Biota = biosequence Topography = Toposequence Parent Material = Lithosequence Time = Chronosequence

______ is a primary silicate mineral that is resistant to weathering and is dominate in these two texture classes ______ & _____. A. mica, silt & clay B. silicate clays, silt & clays C. quartz, clay & silt D. Quartz, sand & silt *from quiz 4*

D. Quartz, sand & silt

"making soil more dense by removing air space" is the definition for: A. consistence B. expansion C. compressibility D. compaction

D. compaction

M(solids) / V(solids) is the equation for: A. bulk density B. stokes law C. porosity density D. particle density

D. particle density

Which term is best described by the following definition? "is the actual amount of precipitation penetrating the regolith" and is influenced by: - temperature/evaporation - permeability - season - topography

EFFECTIVE PRECIPITATION

What is the key difference between eluviation and illuviation?

Eluviation is the depletion of clay, oxides, organic matter and other elements aka LEACHING Illuviation is the zone of accumulation for clay, oxides, organic matter and other elements transported from above

T/F Secondary minerals have experienced little alteration

F A L S E Secondary minerals have been weathered or broken down aka composition has been altered examples include > silicate clays (smectite) > iron oxides (goethite)

T/F *Horizons* develop below the bedrock and are equal in thickness.

False, horizons develop *above* the bedrock and vary in thickness. - horizons are not always so clearly distinct

T/F Larger particles (in soil aggregation) are better.

False. While both are needed, larger particles are more fragile and easily lost via management

___ and ___ oxides are the *most resistant* to weathering.

Fe and Al

Given the following mode of transportations, what are the corresponding parent materials? Ice Flowing water Gravity Wind Lake Ocean In pace ( non-transported)

Ice = glacial till flowing water = alluvium; outwash gravity = colluvium wind = tephra; loess' aeolian lake = lacustrine ocean = marine in place = residual (residuum)

What are the differences between MICROpores and MACROpores? *both these elements make up porosity*

MICROpores: - aka mesopores - <0.08 mm - small pores that are last to dry out because water is held tightly (clay) - slow conductor of water - water move by capillary movement against flow of gravity MACROpores - > 0.08 mm - super highway for water and air - water drains out via gravity > filled with water only when saturated

_____ rocks are made by heat or pressure.

Metamorphic - made from igneous or sedimentary rocks when earth continental plates shift ex. granite > schist granite/sandstone > quartzite shale > slate limestone > marble

What are the 4 main components of soil and what are their relative proportions to the composition of soil?

Mineral matter -- 45% Organic matter -- 5 % Soil Water -- 25% Soil Air -- 25%

What are mottles and what do they indicate?

Mottles = spots in soil where Fe has different redox environment indicate changing moisture conditions

What is the order of the horizons and what is the major characteristic of each particular horizon?

O = Organic horizon A = first mineral layer E = layer of Eluviation B = layer of illuviation C = parent material

Which of the 5 soil forming factors is best defined by the following characteristics? -Architects of soil by > vegetation of roots and litter inputs > small animal inputs and burrowing > insects > microorganisms - influence nearly every aspect of soil functioning and formation via > organic matter dynamics > nutrient cycling > pH > weathering > profile mixing > erosion potential

ORGANISMS

Which of the 5 soil forming factors is described by the following characteristics? - comes from many different sources - is not static - chemical and physical properties most influence soil development - *classified based on mode of transportation*

PARENT MATERIAL

What is *Particle Density*?

PD = mass per volume of dry solids - if unknown, the constant 2.65 is used

____ weathering is the disintegration or structural breakdown of rocks influenced by temperature, abrasion of water, wind & ice and plants & animals.

PHYSICAL

Which mineral is a primary silicate mineral that is resistant to weathering?

QUARTZ

A ____ reaction is a reaction including electron transfer change in oxidation states

REDOX REACTION

Which of the 5 soil forming factors is described by the following characteristic: - Hillsides = shallow > erosion - Hilltops = deep, light in color > leaching - Valleys = deep, dark, more horizons > deposition > accumulation > increased moisture

RELIEF

What are the layers of the earth's sphere in relation to what they contain? Hint: which layers of earth do rock, groundwater, soil and biota belong to?

Rock = lithosphere Groundwater = hydrosphere Soil = pedosphere Biota = biosphere

Between sand, silt and clay, which particle is the largest and has the lowest affinity for water, nutrients and each other?

SAND

Between sand, silt and clay which is medium sized, had moderate affinity for water and each other but has low affinity for nutrients?

SILT

The soil state factor equation by Hans Jenny in 1941 looks like:

SOIL = (Cl, O, R, P, T) Cl = Climate O = Organisms (biota) R = Relief (topography) P = Parent Material T = Time

What is the strength of attraction of particles between sand, silt and clay?

Sand = low silt = medium clay = high

What are the means of observation for sand, silt and clay, respectively?

Sand = naked eye Silt = microscope Clay = electron microscope

What are the dominant minerals (primary or secondary) present in sand, silt and clay, respectively?

Sand contains primary minerals. Silt contains primary and secondary minerals. Clay contains Secondary minerals.

_____ rocks are formed when weathering products are released from other, older rocks containing primary or secondary minerals. *most common rock*

Sedimentary formed by: > deposition, recrystallization > compaction or cementation EX: Granite > quart sand > [cemented by Ca, Fe, I in water] > sandstone

What are the 3 components to fully describe soil structure?

Shape Size Grade

T/F Highly weathered soils (older soils) are soils the contain mostly secondary minerals?

T R U E - weathering releases elements such as > Si > Fe > Al - more soluble elements get leached out > Na > K > Ca > Mg

T/F Primary minerals have experienced little alteration

T R U E examples of primary minerals include > quarts > mica > feldspar

Which of the 5 soil forming factors is described by the following characteristics: - research approach: > chronosequence > glacial retreat - soil ecosystem development > driven by physical structures and hydrological processes > the importance of chemical processes increases > biological communities drive ecosystem properties and development

TIME

T/F Gypsum can be found in the sulfate mineral class?

TRUE - gypsum is relatively soluble

T/F *Parent Material* is the deepest layer of *soil*.

True

Soil starts from ____, that break up rocks and minerals via physical, chemical and biological processes.

W E A T H E R I N G - can also create new minerals

Smaller particles, transformation of primary minerals into secondary minerals, transformation of less stable to more stable minerals, release of nutrients in soluble forms and resistant primary minerals are all products of ______.

WEATHERING

The following are all *TRUE* characteristics of subsoil: > not as affected by soil forming factors > lighter in color (less soil organic matter) > less biological activity > more compacted, less pores > often enriched in clay

Yes, all characteristics are TRUE about subsoil

Which of the following properties *does not* influence the ability of soils to hold, transport and exchange water, air and nutrients? a. color b. texture c. structure d. volume

a. color

"property that a soil has of itself, independently of other things and is difficult/impossible to change without changing the soil itself" is the definition of: a. intrinsic/inherent soil structure b. soil structure c. extrinsic/dynamic soil structure d. soil texture

a. intrinsic/inherent soil structure

For the soil color 7.5 YR 3/4, the hue is: a. 7.5 b. 7.5 Y/R c. 3 d. 4

b. 7.5 Y/R

"soil's tendency to shrink/swell" is the definition for A. atterberg limits B. expansion C. compressibility D. consistence

b. expansion

Chemical weathering processes include all of the following except: A. complexation B. h2o abrasion C. hydrolysis D. reduction

b. h2o abrasion

which properties are associated with clay sized particles? a. high drainage, high susceptibility to water and wind erosion b. high-water holding capacity, poor aeration, high nutrient storage capability c. dust in the wind

b. high-water holding capacity, poor aeration, high nutrient storage capability

from a biological point of view, the most important role of structural development in clayey textured soils is to provide an increase in: a. total porosity b. macro porosity c. texture d. bulk density

b. macro porosity

the structure of a soil horizon is moderate, medium, granular. the structural size of the horizon is: a. moderate b. medium c. granular

b. medium

After a growing season of heavy tillage traffic across a soil, a soil property that is least affected is: a. aeration porosity b. particle density c. structure d. compaction

b. particle density

a common primary silicate mineral which is resistant to weathering to form is: A. apatite B. quartz C. calcite D. hornblende

b. quartz

"Property that is NOT inherent to the soil and can be changed depending on the context, circumstance and/or management" is the definition of: a. intrinsic/inherent soil structure b. soil structure c. extrinsic/dynamic soil structure d. soil texture

c. extrinsic/dynamic soil structure

To determine the bulk density of an undisturbed soil core, one must know its oven dry weight and a. partical volume b. pore volume c. total volume d. water volume

c. total volume

weathering is greatest in a. tropical, arid climates b. arctic, arid climates c. tropical, humid climates d. arctic, humid climates

c. tropical, humid climates

Consistence is influenced by the degree of _______ & moisture content

cementation

What is chroma?

chroma = how much color is present (0-10, none to all) - 6 or more (and with R or YR hue) is likely to be red orange

What practices are used to reduce the impact of tillage?

conservation tillage. this method minimizes tillage and conserves residues on surface

Why do clay- textured soil have greater porosity compared to sandtextured soils? a. because clays have high bulk density b. because clay have higher CEC c. because clays shrink d. because clays have numerous micropores

d. because clays have numerous micropores

T / F Less total pore volume = greater porosity

false!! less total pore volume = less porosity greater total pore volume = greater porosity

T/F fine textured soils (like clay) have higher bulk densities than coarse textured soils.

false, they have a lower bulk density. why? = clays have pore space within aggregates and among aggregates; therefore, more pore space and lower BD.

High temps & low precipitation mean the soil will have a ____ pH. Low temps & high precipitation mean the soil will have a ____ pH.

first blank = higher second blank = lower

Climate and Organisms are _____ factors, while Topography, Parent Material and Time are _____ factors in soil.

first blank: active second blank: passive

Fill in the blanks: _____ intact water molecules binds with a mineral, where as ______ is the separation of water into OH- and H+ at mineral surface which often releases a nutrient (cation) from mineral.

first blank: hydration second blank: hydrolysis

Another name for soil water is ____ ________ and is important for transport of ______.

first blank: soil solution second blank: nutrients (plants, organisms)

Plasticity vs Stickiness _____ is the moisture content at which the soil adheres to fingers and thumb ______ describes the moldability of soil; whether it can be rolled into a thin thread

first blank: stickiness second blank: plasticity both are related to the type and amount of clay and organic matter

What are the 2 factors influencing aggregation in soils?

flocculation (clumping) cementation (stabilization)

What is Hue?

hue = color - reds = oxidized and dry (hematite Fe compounds present) - yellows = oxidized and moderately wet (goethite Fe compounds present) - grey/green/blue = reduced and very wet (reduced Fe compounds present) 0 (no hue color) - 10 (all hue color)

Soil organisms, organic matter and tillage are all practices affecting aggregation. Of the 3, which improve and which destroys?

improves: soil organisms and organic matter destroys: tillage

Sandy soils have less/greater pore volume and smaller/greater soil pore size than clay.

less, greater

Depressions + water infiltration =

more weathered regolith and more advanced profile development

If you have more effective moisture reaching the regolith, do you have more or less weathering?

more weathering

To have a reduction reaction is to ____ an electron. To have an oxidation reaction is to ____ an electron.

reduction = gain electron (making atom more negative) oxidation = lose electron (making atom less negative)

Topography reflects the distribution of ______, _______ and ______ parent materials.

residual, colluvial, alluvial

What is the consistency of sand, silt and clay when wet?

sand = loose, gritty silt = smooth clay= sticky, malleable

What is the strength of attraction of particles between sand, silt & clay with water?

sand = low silt = medium clay = high

What is the consistency of sand, silt and clay when dry?

sand = very loose, gritty silt = powdery, some clods clay = hard clods

What is the capability of nutrient storage for sand, silt and clay?

sand = very low silt = low clay = high

What are the short/long term affects of tillage on bulk density and porosity?

short term = may decrease BD and increase porosity long term = increases BD and decreases porosity Why? - weakens soil structure - depletes organic matter that might cement aggregates together

What is the term that is best defined by the following characteristics? - ventilation system of soil - concentrations are spatially heterogeneous - has more water vapor and carbon dioxide and less oxygen compared to the atmosphere - contribute roughly 25% to an ideal soil structure

soil air

What is the term that is best defined by the following characteristics? - driven by climate - determines ecosystem productivity - important in soil formation

soil moisture

What are the 4 soil forming processes for soil?

transformations translocations additions losses

T/F The space between solids are occupied by air, water and microorganisms

true

What is value?

value = darkness or lightness (0-10) - 4 or less = organic matter is likely to be present

What are the 5 sizes soil can be classified as?

very fine fine medium coarse very coarse