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FINE-EARTH FRACTION - that portion of the soil particles which has diameter of less than 2 <br /> millimeters. <br /> FINE-LOAMY - by weight, a textural class in which the fine earth fraction has 18 to 34 <br /> percent clay and greater than 15 percent fine or coarser sand. <br /> HORIZON (SOIL) - contrasting layers of soil material approximately parallel to the land <br /> surface and differing from adjacent layers in physical , chemical, and biological <br /> properties of characteristics. <br /> A HORIZON - commonly the uppermost mineral layer in the soil profile often referred <br /> to as the surface soil . It is the horizon where humus is accumulative or formed and <br /> also called the zone of eluviation. <br /> B HORIZON - the master horizon commonly found immediately beneath the A horizon and <br /> often called the subsoil or zone of illuviation. <br /> C HORIZON - a mineral like layer, excluding bedrock or unconsolidated lithologic <br /> materials, that is only slightly affected by pedogenic processes and lacks properties <br /> diagnostic of A and B horizons. It is often called the substratum. <br /> MESIC - a soil temperature regime with mean annual soil temperature between 8 and 15 <br /> degrees Centigrade (47-59 degrees Fahrenheit) at a depth of 20 inches, and the <br /> difference between mean summer and mean winter soil temperature is more than 5 <br /> degrees Centigrade (9 degrees Fahrenheit). <br /> MODERATELY DEEP - the soil is 20 to 40 inches deep over bedrock. <br /> MOTTLING, SOIL - irregular spots of different colors that vary in number and size. <br /> Mottling generally indicates poor aeration and impeded drainage. <br /> PARALITHIC CONTACT - boundary between soil and hard (greater than three on Moh's scale), <br /> continuous, coherent underlying materials. Roots generally do not extend below a <br /> paralithic contact. Much disagreement exists concerning the nature and placement of <br /> the paralithic contact. <br /> 9-5-33 Revised 08/19/88 <br />