Characterization of chemically fixed nitrogen-15-labeled liquid anhydrous ammonia and of biologically immobilized nitrogen-15 in typical Illinois mollisols

An investigation was carried out into the chemical nature and further transformation of fixed liquid anhydrous NH$\sb3$ with emphasis on chemical fixation of NH$\sb3$ by soil organic matter. For this purpose, $\sp{15}$N-labeled liquid anhydrous NH$\sb3$ was injected into a Drummer soil. The fixed $\sp{15}$NH$\sb3$ was sequentially extracted with 0.15 M Na$\sb4$P$\sb2$O$\sb7$ and 0.15 M KOH, and the extracted N was fractionated into humic acid (HA) and fulvic acid (FA). The residual soil was then extracted with 0.1 M NaOH and 99% (v/v) dimethyl sulfoxide (DMSO). The FA fraction was further separated into low molecular weight (LMW) and high molecular weight (HMW) components by equilibrium dialysis, and into generic FA and nonhumic substances by sorption-desorption from XAD-8 resin. The results show that: (1) chemical fixation by soil organic matter accounted for 36% of the total fixed NH$\sb3$; clay fixation accounted for 52%; (2) of the chemically fixed NH$\sb3$-N, 55% was recovered in the FA fraction and 17% as HA by sequential extraction with Na$\sb4$P$\sb2$O$\sb7$ and KOH, 11% was further recovered by extraction with NaOH and DMSO, and 17% remained as humin; (3) most of the N extracted by Na$\sb4$P$\sb2$O$\sb7$ and KOH was recovered in the FA fraction of which about three-fourths occurred in either the LMW fraction or as nonhumic substances; (4) about 13% of the newly fixed NH$\sb3$ was available to soil microorganisms, and 22% was potentially available to higher plants; and (5) incubation with glucose led to stabilization of the newly fixed NH$\sb3$ through biological immobilization.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Crop Sciences

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2011

Author dc:creator

• He, Xin-Tao

Contributors dc:contributor

• Mulvaney, Richard L.

• Agriculture, Agronomy
• Chemistry, Agricultural
• Environmental Sciences

Statement dc:rights

• Copyright 1990 He, Xin-Tao

Language dc:language

eng

Identifier

AAI9021696
(UMI)AAI9021696

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/20000