Submitted to: Environmental Science and Technology
Publication Type: Abstract Only
Publication Acceptance Date: 8/31/2007
Publication Date: 9/12/2007
Citation: Tazisong, I.A., Senwo, Z.N., He, Z., Taylor, R.W. 2007. Composition, Stability, and Interactions of Organic Matter Fractions in an Ultisol. Environmental Science and Technology. Meeting abstracts pg. 11.
Technical Abstract: Humic substances (HS) are usually divided into three components based on their solubility in various media (humic acid (HAs), fulvic acid (FAs) and humin). Data on the chemical composition, functionality, and properties of HAs and FAs extracted from ultisols impacted by various soil management practices are limited. Our objective was to study the stability and reactivity of HAs and FAs extracted from an ultisol that has been under a combination of management practices [no-tillage, mulch tillage, and conventional tillage, two cropping systems (rye and cotton), and two fertilizer sources (NH4NO3 and poultry manure)]. HAs and FAs were extracted using procedures outline by the international humic substances society. After extraction, 0.01 g of HAs and FAs were incubated with organic phosphorus compounds for 24 hr and hydrolyzed with phytase and acid phosphatase to investigate any resistance of bound phosphorus compounds to phosphatase. Additionally, trace metals [Fe, Cd, Zn, Ni, Pb, and Cu] ranging in concentration from 1-50 ppm were also incubated with HAs for 48 hr to study the preferential and relative complexation of these potential pollutants by HS. Our results showed that the composition of HAs and FAs was slightly affected by management practices as revealed by FT-IR spectra. Our results also showed that phytate adsorbed on HAs was more resistant to phosphatase hydrolysis than phytate adsorbed by FAs. Relative and preferential adsorption of the trace elements was in the order of Fe>Cu>Pb>Cd>Zn>Ni. These results demonstrated that interactions among humic substance, metal, and phosphorus play important roles in governing hydrolysis of organic P in soil environments.