Soils 210 chapter 4 review – Flashcards
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T/F wet, moist, and dry are descriptive terms for soil consistence moisture levels
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T
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T/F tilth is a general term for the physical condition of tilled soil and takes into account texture, permeability, structure, and consistence; how easy the soil is to till; how good a seedbed can be made; how easily seedlings can emerge; how easily roots can grow
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T
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T/F soil temperature is fairly static and not subject to the influences of many factors
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F
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T/F in soil, there are 14 textural classes
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F
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T/F a smart grower will approach using soils by taking the following things in to account 1. selecting a crop that will fit the soil 2. managing the soil in a manner that fits the texture 3. improving texture by adding organic material
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T
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In the ribbon or feel test for determine soil texture, what indicates loamy sand?
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no ribboning
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total pore space is a measure of soil volume indicating how much it?
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holds water and air
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what physical property is least likely to be altered by growers?
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texture
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if soil texture were the same, which soil would be most permeable?
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one with granular structure
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a soil that is 20% clay and 20% sand is
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silty loam
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Y/N does pressure applied to the soil surface cause compaction
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Y
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Y/N does soil particle size affect soil features other than specific surface area and the number and size of pores?
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N
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Y/N is it true that texture in large areas of soil can be modified easily?
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N
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Y/N does total pore space measure soil volume that holds air and water?
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Y
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Y/N are the three groups of traits scientists use to falsify soil structure type, class and grade?
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Y
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Particle density varies according to the type of ______ in the parent material and the amount of organic matter in the soil
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minerals
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the most fundamental soil property that influences other soil traits is _____
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texture
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Sand, silt, and clay make up the fine earth ______ of soil used to determine texture
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fraction
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_____ soils are easiest to use for landscapes and gardens
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loamy
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soil structure refers to the way soil particles clump together into larger units. these large units are called _____
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aggregates
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sand behaves as individual grains and is considered a ____ soil
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structureless
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occurs where extreme illation has caused a very high clay content in a subsoil layer
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claypan
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layers of soil in which chemicals cement soil particles together
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caliche
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layers of soil cemented by a special type of clay common to the tropics
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plinthite
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clay binds soil particles into a hard, brittle layer
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fragipan
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tend to occupy lower B and C horizons; peds are 1/5 to 4 inches, forming angular columns that stand upright in the soil
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prismatic structure
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usually found in E horizons; peds are large but thin, plate-like, and arranged in overlapping horizontal layers
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play structure
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commonly found in A horizons; peds are 1/25 to 2/5 inch; rounded in form; considered the most desirable of structures
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granular structure
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typical of many B horizons; peds are 1/5 to 2 inches
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blocky structure
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small particles; many small pores; consisting mostly of tiny sheet-like crystals
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clay
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a soil in which sand, silt, and clay contribute equally to the soils properties
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loam
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large particles; composed mainly of weathered grains of quartz or other minerals
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sand
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medium-sized particles; silky or powdery to the touch
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silt
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the mass of a volume of undisturbed of undisturbed oven-dry soil
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bulk density
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the ease with which air, water, and roots move though soil
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permeability
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the measure of the rate of water movement through a soil
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infiltration
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soil characteristics that can be seen or felt
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physical property
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may indicate that chemicals have leached out or may be due to accumulations of lime, gypsum, or other salts
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white to light grey
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result from oxide iron minerals
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light brown, yellow to red
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result from high levels of organic matter
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dark brown to black
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patches of different colors that suggest the soil is waterlogged for part of the year
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mottled
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result from reduced iron compounds
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blueish-grey
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soil particles coming together to form aggregates
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flocculation
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distinctness of structure; sometimes referred to strength of structure
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grade
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a measure of soil response to pressure
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soil consistence
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substance produced by fungi an bacteria that helps form aggregates
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glomalin
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how easily soil can be molded
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plasticity
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