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�U OF SOIIS CLASSI�ATION SYSTEM <br />U. S. BUREA <br />We �ase the U. S� Bureau of Soils method of soil classification which is baseci on the <br />texture of the soil, The texture of a soil is influenced by the amount of the various <br />sizes of soil particles in the soil. The soil part�.cles are grouped into three <br />particle size classifications as follows: <br />Partiele--Size l?iameter of U. S. Standard <br />Classification Partic�.es Millimeters) Sieve <br />Sand 2.0 to 0.05 #10 to #270 <br />Silt 0.05 to 0.005 (Cannot be separated <br />Clay Smaller �han 0.00 5 by sieving) <br />Soil i.s grouped into tw�lve <br />silt and clay pr�sent in the <br />triaxial graph. <br />bas�.c classifications according to the percentages of sand, <br />soil. These cla,ssifications are shown by the following <br />100 <br />CLAY <br />A NDY � <br />�p . CLAY <br />S� NDY <br />zQ CLAY LOAM <br />SANDY <br />0 <br />SILT <br />CLAY � <br />IL <br />CL <br />CI�Y LQAM SIL <br />, CLAY <br />LOAt�i <br />, •l ' ' � . <br />1� � <br />i��'. •� :� � <br />.� <br />SILTY <br />LQAM <br />� SILT 100� <br />20 0 <br />This same classification �yst�m in tabul�r form is as follows: <br />BASIC SOIL CLASSiFIC�:TION <br />sana <br />Loam�y sand. <br />Sand,y loam <br />Loam <br />Si1ty loam <br />Silt <br />sandy clay loam <br />clay loam <br />Silt3� clay loam <br />clay <br />Saridy clay <br />Silty clay <br />�, ND <br />90- o� <br />80 - 90 <br />�0 - 80 <br />30 - 50 <br />0-50 <br />0-20 <br />50 - 80 <br />20 - 50 <br />0-30 <br />o_So <br />50 - ?o <br />0 - 2.0 <br />SILT <br />0 - 10 <br />o-zo <br />0_50 <br />.30 _ So <br />50 - aa <br />80 - lOQ <br />0-30 <br />zo -. 50 <br />50 - 80 <br />o - 50 <br />o-zo <br />50 - ?o <br />CLAY <br />0 - 1 <br />o-Zo <br />0-20 <br />0-21� <br />0-20 <br />0-20 <br />zo - 30 <br />zo - 30 <br />zo - 30 <br />30 - ioo <br />30 - 50 <br />3o-So <br />We class�.fy the sand present in a soil as c4�.rse (��1U -�1�20 si�ves) , medium (#20 -�40 <br />sieves), fine �#40 -#100 �ieves), very fine (#100 -�270 sieves)� or as well graded. <br />Soi1.� with an appreciabl� amaunt of gravel �r°eseizt ax�e classified "tilith a little gravel" <br />(less than 15�), "with some g�°avel" (15 to 30;b), "�rith gravel" (30 to 50�) �"and gravel" <br />(over 50`�). Material over 3 inches is classified as boulders. Organic soil is classified <br />as"pemt" (over 2�3 organ�c material) or "muck" (1/3 to 2/3 organic material). <br />(3-15-61? <br />