Abstract

An investigation was undertaken to determine morphological, physical, chemical. and mineralogical properties of pans having fragic characteristics in horizons of selected Southern Coastal Plain Soils. Soil sories involved were Carnegie (Plinthic Paleudults), Cowarts (Typic Hapludults) and Irvington (Plinthic Fragiudults). Pans were strongly indurated at the top and hardness gradually decreased with depth. Pans were firm when moist and very hard when dry and ranged from 15 to 45 cm in thickness. There was no evidence that particle size distribution was related to pan formation. Organic matter Content, pH, and available P of the epipedon were higher than subsurface horizons although magnitude varied from soil to soil. Cation exchange capacity was fairly consistent in a given horizon for each pedon and was related to organic matter and clay content. Exchangeable Mg content of pans was higher than exchangeable Ca. Pans did not influence the distribution of exchangeable Na, K, Zn, Fé,. and Mn. Horizons having fragic characteristics were not related to gross soil mineralogy or clay mineralogy: Close packing of particles and possible surface tension effects due to the structure of the water molecule apparently influenced the bonding which, resulted in the brittleness in the pan formations. (Key words: Genetic pans, Gragipans, pans, Sub surface horizon).

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