Submitted to: International Soil Science Society Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2003
Publication Date: 7/13/2003
Citation: He, Z., Honeycutt, C.W., Griffin, T.S. 2003. Characterization of organic phosphorus in animal manure and soil by systematic phosphatase hydrolysis. International Soil Science Society Conference Proceedings. Ascona, Switzerland. P 16
Technical Abstract: Phosphatase hydrolysis has been emerging as an alternative tool to characterize organic phosphorus in soil, animal manure, and other sources. Whereas many phosphate-releasing enzymes have been used for this purpose, the variety of the enzymes and incubation conditions often complicate data analyses and comparison. We tested a systematic hydrolysis procedure to characterize hydrolysable organic P in swine manure and soils. We applied 1) acid phosphatase from potato, 2) acid phosphatases from both potato and wheat germ, and 3) both phosphatases plus nuclease P1, to identify and quantify simple monoester P, phytate (inositol hexaphosphate)-like P, and DNA-like P, respectively, in 100 mM sodium acetate (pH 5.0). The stepwise addition of enzymes minimizes potential errors arising from overlapping or incomplete substrate specificity in separate hydrolysis incubations. The single pH/buffer conditions reduced background errors associated with different pH and buffer systems used in other hydrolysis investigations. We then investigated, using the enzymatic approach coupled with sequential extraction, the change of P forms in soil and soils mixed with fertilizer or dairy manure in laboratory incubation experiments. Hydrolysable organic P (mainly in the phytate-like form) was interchanged in sequentially extracted H2O, NaHCO3, and NaOH fractions over time, following trends similar to inorganic P. Time course analysis also allowed examination of organic P transformations between enzymatically hydrolysable and non-hydrolysable fractions. Our study demonstrates that enzymatic hydrolysis is an effective approach to determine and monitor organic P transformations.