Thursday, November 16, 2006 - 9:45 AM

Phosphorus Sorption Characteristics of Tifton Soil Amended with Pyrolysis-derived Chars.

Leticia Sonon1, Keith Harris2, Julia Gaskin2, and K.C. Das2. (1) 2400 College Station Road, University of Georgia, University of Georgia, Ag & Environmental Services Laboratories, Athens, GA 30602, (2) Dept. of Biol. & Ag. Eng., Univeristy of Georgia, Athens, GA 30602

Sorption of phosphorus (P) was studied on Tifton soil amended with pyrolysis-derived chars. Chars were sourced from peanut hulls (PH), pine chips (PC), hardwood red (HR), and pine bark (PB), all pyrolyzed at 426oC and with particle size <420 µm. Prior to use, the chars were washed with deionized water to remove soluble salts. Chars were added to soil at a rate of 0.05 g char g-1 soil and an unamended soil was included to serve as control. Soils were equilibrated with five concentrations of P (0, 5, 20, 50, and 100 mg P L-1) in 0.01M CaClmatrix following the batch techniques. As the solution concentration of P was increased, the amount of P sorbed correspondingly increased, but the magnitude of sorption differed in some char treatments. Amount of P sorbed was highest in soil amended with PH, while the lowest P sorption occurred in unamended soil. Amount of P sorbed was comparable in soils with PC, HR, and PB char amendments.  The surface functional groups on the sorbent surface will be detected by Fournier transform infrared spectroscopy.  Understanding the influence of pyrolysis-derived chars on the fate and mobility of P in the environment will be discussed.