Soil Formation and Properties: Terms and Definitions, Quizzes of Soil Physics

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TERM 1 lithosphere, atmosphere, hydroshere, biosphere, pedosphere DEFINITION 1 rock air water living things soil TERM 2 regolith DEFINITION 2 the rock exposed at earth's surface has crumbled and decayed to produce a layer of unconsolidated debris overlaying the hard unweathered rock TERM 3 pedalogy DEFINITION 3 study soils as natural bodies, the properties of soil horizons, and the relationships among soils within a landscape TERM 4 edaphologists DEFINITION 4 focus on he soil as habitat for living tings, esecially plants TERM 5 soil profile DEFINITION 5 vertical section exposing a set of horizons in the wall of a pit TERM 6 parent material DEFINITION 6 deepest layers that are most similar to original regolith TERM 7 O horizon DEFINITION 7 organic materials formed on surface, physical and biochemical breakdown TERM 8 A Horizons DEFINITION 8 topsoil dominated by parent mineral particles darkened by accum of OM soils animals and percolating water move OM down TERM 9 E Horizons DEFINITION 9 intensely weathered and leached dont accum OM TERM 10 B horizons DEFINITION 10 silicate clays, iron & aluminum oxides, gypsum, calcium carbonate washed down or ormed in place through weathering TERM 21 exfoliation DEFINITION 21 the peeling away of outer layers, because outer surface of a rock is often warmer or coler than the protected inner portions TERM 22 Biochemical weathering DEFINITION 22 hydration- intact water molecules bind to a mineral hydrolysis- H2O split into H and hydroxl groups, H often replaces cation form mineral struture dissolution- water hydrating catons and anions until hey become dissociated from each other acid rxns- acids increase activity of H+'s in H2O ox-redox- minerals contaning Fe, Mn, S especially susceptible complexation- TERM 23 5 soil forming factors DEFINITION 23 parent material cimate biota topography time TERM 24 colluvium DEFINITION 24 made up of porly sorted rock fragments detached from he heights above and carried downslope TERM 25 floodplains DEFINITION 25 part of river vally thats inundated during floods, alluvial deposit terrqaces- a stream may cut down through its already well-formed alluvial deposits, if theres a change in grade TERM 26 alluvial fans DEFINITION 26 streams that leave a narrow valley in an upland area and suddely descend to a much broader valley below deposit sediment in the shape of a fan, as water spreads out and slows dwn TERM 27 delta deposits DEFINITION 27 much of he finer sediment carried by streams is not deposited in the flooplain but is discharged into the lake, reservoir, or ocean into which the streams flow, some of the suspended materials settle near the river mouth TERM 28 glacil till DEFINITION 28 material of a glacial origin deposited directly by the ice; heterogeneous mixtures of debris, which can vary in size form boulders to clay TERM 29 moraines DEFINITION 29 irregular ridges in which much glacial till is deposited TERM 30 outwash plain DEFINITION 30 frmed by sediment in valleys and on plains where gacial waters were able to flow away freely TERM 31 valley fills DEFINITION 31 sediments, withsands and gravels sorted by flowing water TERM 32 loess DEFINITION 32 compound primarily of silt with some vry fine sand and coarse clay TERM 33 aerosolic dust DEFINITION 33 very fineparticles carried very high int the air TERM 34 peat DEFINITION 34 organic deposits that accum. up to several meters in depth TERM 35 bogs DEFINITION 35 peat accumulating ponds with no outfow and little inflow, recieve litle Ca, acidic fens- same thing except Ca rich and alkaline TERM 46 pedogenic DEFINITION 46 - 4 broad soil forming processes whose varitions brng about profound changes in the regolith during genesis TERM 47 4 pedogenic factors DEFINITION 47 transformations- occur when soil cnstittuents are chemically or phys. modified or destroyed and others synthesized from the precurser materials translocations- movement of inO and O materials laterially within a horizon or vertically from 1 up or down to another addtions- inputs of materials into developing soil prof from outside sources losses- materials are lost from the soil prof by leaching to groundwater, eroson of surface, or other forms of remova TERM 48 O horizons DEFINITION 48 Oi- fibric materials, slightly decomposed Oe- hemic materials, finely fragmented residues intermediately decomposed, much fiber Oa- sapric materials, hghly decomposed, smooth amorphous residues, dont contain much fiber TERM 49 eluviation DEFINITION 49 zoes of maximum leaching TERM 50 illuviation DEFINITION 50 materials accumulated by washing in fom above horizons TERM 51 solum DEFINITION 51 A and B horizns TERM 52 R layers DEFINITION 52 consolidated rock with little evidence of weathering TERM 53 pedon DEFINITION 53 smallest sampling unit that displays full range of props characteristic of a particular soil TERM 54 soil series DEFINITION 54 all the soil individuals that have in common a suite of soil profile prps and horizns that fall within a particular range TERM 55 epipedons DEFINITION 55 diagnostichorizons that occur at the cell surface TERM 56 mollic ep DEFINITION 56 mineral surface horizon noted for itsdark color form OM, thickness, and fr itys softness even when dry moist 3 months of year when 5 C or higher at depth of 50 cm under grassland TERM 57 umbric ep DEFINITION 57 same characteristic as mollic except % base sat. is lower areas of higher ranfall where parent aterial has lower content of Ca and Mg TERM 58 ochric ep DEFINITION 58 minera horizon thats either to thin, too light in color, or too low in OM to be umbric or mollic may be hard and massive when dry TERM 59 melanic ep DEFINITION 59 mineral horizon that is black in color due to high OM content high in allophane nd similar minerals developed from volcanic ash more than 30c hick, light and fluffy TERM 60 histic ep DEFINITION 60 20-60 cm thick layer of organic soil materials overlying mineral soil formed in wet areas layer of peat or muck dark brown to black low density TERM 71 Duripan, fragipan, and placic hors DEFINITION 71 subsurface diagnostic horizons are materials cemented or densely packed, resulting in reltively impermeable layers can resist water movement and penetration of plant roots may encourage water runoff and erosion TERM 72 SMR DEFINITION 72 Soil moisture regimes- the presence or absence of either water-sat cnditions or plant available soil water during specified periods in the year in what is termed the control section of the soil TERM 73 spodosols DEFINITION 73 acid sandy forest soils, highly leached occur most on coarse textured acid parent materials moist to wet areas under forest veg, esp. coniferous TERM 74 oxisols DEFINITION 74 oxic horizon, highly weathered most highly weathered soils hot climates, nearly yearrund moist conditons high clay content of low activity, not sticky resistent to erosion TERM 75 Inceptisols DEFINITION 75 few diagnostic features, incption of B horizn prominent in mountainour regions most important sil order in lowlnd rice growing areas of asia TERM 76 andisols DEFINITION 76 volcanic ash soils yung soils no time to becme highly weathered TERM 77 gelisols DEFINITION 77 permafrost and frost churning young wth little proile development cold teps slow soil formation cryoturbation- physical distrubance of soil materials caused by formation of icewedges and by expansion and contraction of water as it freezes and thaws TERM 78 histosols DEFINITION 78 organic soils without permafrost little prof. develop anaerobic environment TERM 79 udic ep DEFINITION 79 soil moisture is sufficiently high year round in most years to meet plant needs humid, 1/3 of wrld land area extreely wet moisture regim with excess moisture for leaching throughout the year is termed perudic TERM 80 ustic DEFINITION 80 soil moisture is intermediate between udic and aridic regimes TERM 81 aridic DEFINITION 81 soil is dry for at least half of growing season and moist for lessthan 90 days consecutive TERM 82 xeric DEFINITION 82 soil moisture regime found in typical mediterranean type climates, with cool moist wnters and warm dry summers TERM 83 6 hierarchial categories of classification in soil taxonomy DEFINITION 83 order (broadest)- aridisols suborder- aquents, arents, fluvents Great Group- argiaquolls- aquolls of clay or argillic horizons Subgroup Family Series TERM 84 Soil phases DEFINITION 84 field of soil surveying practical subunits, soil series are further differentiated into the basis of surface, texture, degree of erosion, slope , or other characteristics TERM 85 soil orders DEFINITION 85 each of the worlds soils assigned to one of 12 orders largely based on sil props that reflect a major course of development, with considerable emphasis placed on presence or absence of major diagnostic horizons TERM 96 platy shape DEFINITION 96 unitsare flat and platelike oreinted horizontally mainly in E and B horizons, unless surface is compacted formed by freeze expansion or compaction, or emain from bedding planes TERM 97 prismatic shape DEFINITION 97 easy to physically seperate units bounded by flat to rounded vertical faces TERM 98 blocky shape DEFINITION 98 units are blocklike or polyhedral bounded by flat or slightly rounded surfaces that are casts of he faces of surrounding peds TERM 99 rock controlled structure DEFINITION 99 bedrock is at least very slightly cemented, if soil forms rock weathering and retains the rock shape, horizon is said to contain rock-cntrolled structure if has the layering associated with many rocks, but has never been ock, I call it flood controlled TERM 100 Describe structure by... DEFINITION 100 strength, size, type TERM 101 soil bulk density DEFINITION 101 dry mass of sil per volume 1g/cm3= density of water slid minerals in soils have avg density of about 2.65 normal range is 1.0-1.8 in mineral soils TERM 102 Macropores are found? DEFINITION 102 between peds of finetextured soils or between sand grains in coarse textured soils TERM 103 Micropores in? DEFINITION 103 are the packing vids between fine clay and fine silt grains sandy soils have more macroporosity, less microporosity and less total porosity TERM 104 factors affecting pore space DEFINITION 104 aggregation increases total pore space higher the OM cntent, the better the aggregation as wetting/drying, freezing/thawing, shtrinking/swelling cycles increase, and tillage and other sources of compaction are avoided, structure integrity and macropore space increases Fe-oxides clay coatings and humus coatngsstabilize sil particles and aid aggregation TERM 105 number 1 limitation to plant growth in mine soils worldwide? DEFINITION 105 severe compaction, no roots in the Cd horizon TERM 106 factors promoting aggregation DEFINITION 106 polyvalent rather than monovaent exchangeable cations like Na shrink/swell from wet/dry and freeze-thaw cycles active microbial biomass generating humic substances FE and Al oxides stabilize many aggregates TERM 107 Good Tilth DEFINITION 107 titlth is an old term used to describe physica condition of the soil in relation to plant growth god tilth means the soil is loose, nonplastic and not dense TERM 108 engineering props DEFINITION 108 cohesion and strength compession and compactibility expansion or shrink-swell potential TERM 109 cohesion vs adhesion DEFINITION 109 water molecules attracted to themselves (cohesion) due to H bonding also cause water to stick to surfaces (adhesion) TERM 110 Capillary rise in diff soils DEFINITION 110 rise in sandy soils is rapid but low in finer textures soils is slower but higher over time TERM 121 unsaturated flow DEFINITION 121 once soil macropors empty via saturated flow dwnward, remaining water is affected by strong matric potential orces rate of water movement drops, water has to crawl unsaturated flow rates are proportional to the diff in matric potential between soil zones TERM 122 infiltration DEFINITION 122 process whereby waterfirst enters the soil surface and is controlled primarily by aggregation ad texture of the A horizon rate of infiltration is enhanced by large aggregates and macropores which tends t b increased by OM, but decreased by tillage over time TERM 123 max retentive capacity DEFINITION 123 when soil is saturated, all macropores are filled, but gravitationa water raidly perclates downward from macropores the maximum amount of water the soil can hold TERM 124 field capacity DEFINITION 124 once the soi loses its gravitational water downward, water that is held up the soil aganst leaching is bund there by matric forces in the thicker portions of the water films extending into macropores soil is now at field capacity -.01- 0.3 bars TERM 125 wilting point DEFINITION 125 as water contnues t be evapotranspired away from he soil, the filmsof water around the soil surfaces become much thineer, so he matric forces holding water get much stronger finally at very thin water films, plants will wilt becuase they cant pull water off the soil -15 bars TERM 126 Plantavailable water in a soil is? DEFINITION 126 taken as the difference between water held at field caacity and wilting point TERM 127 factors affecting water availibility DEFINITION 127 texture OM compaction- decreases mwater availibility thrugh lack of pore space intercnnection weakin structures- less mscropores layering- perches water at contacts TERM 128 free energy of water DEFINITION 128 is decreased by its attaction to soil surfaces and ions in solution (Made more negative) is increased by the downward pull of gravity ( made more positive) when it is above the water table, sea level, or a similar point of ref TERM 129 water avilability to the plant is governed by... DEFINITION 129 combination of soil physca prps and how water content and potentials change with ime TERM 130 P=? DEFINITION 130 P= ET + SS + D precip evapotranspiraton soil storage discharge TERM 131 when the rae of rainfall exceeds the infiltration rate of the soil... DEFINITION 131 net runoff results TERM 132 soil storage DEFINITION 132 water held up against leaching available for evaporation and transpiration by plants TERM 133 mitigation ratio DEFINITION 133 due to ucertainties of success, orested wetlands must be created at 2:1 mitigation ratio (2 created:1 disturbed) TERM 134 what mitigates high B.D.'s DEFINITION 134 moisture content- in moist to et soils, soil strength is lessened, so during the winter and spring, high B.D. may beless of a limitation soil structure- macropore development associated with soil structure allows root tips to penetrate otherwise massive high strengt sils TERM 135 Redox DEFINITION 135 majority of redox rxns are microbially mediated organic carbon electron source aerobic soils O2 used as terminal electron acceptor as msils become anaerobic microbes must fnd other terminal electron acceptors