SOIL SURVEY

-186-Granular - More or less rounded aggregates with an absence of smooth face sand edges .Amorphous (massive) - A coherent soil mass with no evidence of any distinc tarrangement of soil particles .Single grain - A loose, incoherent mass of individual particles, as in sand .Soil survey - The systematic examination, description, classification and mappin gof soils in an area .Soil texture - The relative proportions of the various soil separates in a soil a sdescribed by the classes of soil texture shown in Figure110 .Size group sfrom 2 mm to 0 .05 mm in diameter are called sand, those from 0 .05 to0 .002 mm are called silt, and those less than 0 .002 mm in diameter arecalled clay . Sands are coarse textured, looms are medium textured, an dclays are fine textured .Figure 109 . Soil textural classes (commo nabbreviations in brackets) .Percentages of sand and cla yin the main textural classe sof soils; the remainder of eac hclass is silt .Soilscape group - A defined and named aggregate of soil bodies grouped togethe ron the basis of similar parent materials, drainage, soil, and profile development .Soilscape map unit - See map unit, soilscape .Solifluction - A type of creep that takes place in regions where the ground freezesto a considerable depth, and as it thaws during the warm seasons the upperthawed portion creeps downhill over the frozen material . The soil moves a sa viscous liquid down slopes of as little as 2 or 3 degrees and may carry rock sof considerable size in suspension .Solum - The upper horizons of a soil in which the parent material has been modifie dand within which most plant roots are contained . It consists usually of the Aand B horizons .