I^ent material The unconsolidated organic and mineral 

 material from which soil forms. 



Permcabilitv 



Residuum 

 [residual soil 

 material] 



Sand 



Sedimentary 

 rock 



Silt 



Slope 



Sodicity 



Soil 



The quality of the soil that enables water to 

 move downward through the profile. Per- 

 meability is measured as the number of 

 inches per hour that water moves down- 

 ward through the saturated soiL Terms 

 describing permeability arc very slow 

 [less than 0.06 inch], slow [0.06 to 0.2 

 inch], moderately slow [0.2 to 0.6 inch], 

 moderate [0.6 to 2.0 inches), moderately 

 rapid [2.0 to 6.0 inches], rapid [6.0 to 20 

 inches], and very rapid [more than 20 

 inches]. 



Unconsolidated, weathered or partly 

 weathered mineral material that accumu- 

 lated as consolidated rock disintegrated in 

 place. 



Soil mineral particles from 2.0 to 0.5 mm 

 in diameter. 



Rock made up of particles deposited from 

 suspension in water. The chief kinds of 

 sedimentary rock are conglomerate, 

 formed from gravel; sandstone, formed 

 from sand; shale, formed from clav, and 

 limestone, formed from soft masses of cal- 

 cium carbonate. There are many interme- 

 diate t)pes. Some wind-deposited sand is 

 consolidated into sandstone. 



Soil mineral particles 0.002 to 0.05 mm in 

 diameter. 



The degree of deviation of a surface from 

 horizontal, measured in percent or de- 

 grees. 



The degree to which a soil is afFeaed by 

 exchangeable sodium. Sodicity is ex- 

 pressed as a sodium absorption ratio 

 (SAR) of a saturated extract. 



Material at the earth's surface that is 

 capable of supporting plants and has 



properties resulting from the effca of cli- 

 mate and living matter acting on earthy 

 parent material over periods of time. 



Soil Depth The depth in inches from the surface to a 



root impeding layer in the soil. The fol- 

 lowing classes are used to express soil 

 depth. 



Deep more than 40 inches deep. 



Moderately deep.... 20 to 40 inches deep. 

 Shallow. 10 to 20 inches deep. 



Soil Profile A vertical section of the soil extending 



through all its horizons and into the par- 

 ent material. 



Soil Series A group of soils with profiles that are al- 



most alike, except for differences in tex- 

 ture of the surface layer or of the underly- 

 ing material. All the soils of a series have 

 horizons that are similar in composition, 

 thickness and arrangement. 



Soil Structure The arrangement of soil particles. Dete- 

 rioration can result from too much water, 

 compaction by heavy machinery, effea of 

 heavy rain on bare soil and excess sodium. 



Soil Texture The relative proportions of sand, silt and 

 clay particles, in a mass of soil. TTic basic 

 textural classes, in order of increasing pro- 

 portion of fine particles are sand, loamy 

 sand, sandy loam, loam, silt, silt loam, 

 sandy clay loam, clay loam, silty clay loam, 

 sandy clay, silty clay and clay. The sand, 

 loamy sand and sandy loam classes may be 

 fiirther divided by specifying "coarse," 

 fine, or very hne. 



Terrace An old alluvial plain, ordinarily flat or 



undulating, bordering a river or a lake. 



Uplaiid Landatahigherelevation, in general, than 



the alluvial plain or stream terrace; land 

 above the lowlands along streams. 



Vertical lift Vertical distance from water source. 



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