Effect of pH and organic acids on nitrogen transformations and metal dissolution in soils

Miscellaneous · Sun Jan 01 00:00:00 EST 1989

OSTI ID:5608107

Fu, Minhong

The effect of pH (4, 6, and 8) on nitrogen mineralization was evaluated in three Iowa surface soils treated with crop residues (corn (Zea mays L.), soybean (Glycine max (L.) Merr.), and sorghum (Sorghum vulgare Pers.), or alfalfa (Medicago sativa L.)) and incubated in leaching columns under aerobic conditions at 30C for 20 weeks. In general, N mineralization was significantly depressed at soil pH 4, compared with pH 6 or 8. The types of crop residues added influenced the pattern and amount of N mineralization. A study on the effect of 19 trace elements on the nitrate red activity of four Iowa surface soils showed that most trace elements inhibited this enzyme in acid and neutral soils. The trace elements Ag(I), Cd(II), Se(IV), As(V), and W(VI) were the most effective inhibitors, with >75% inhibition. Mn(II) was the least effective inhibitor, with <10% inhibition. Other trace elements included Cu(I), Co(II), Cu(II), Fe(II), Ni(II), Pb(II), Zn(II), Al(III), As(III), Cr(III), Fe(III), V(IV), Mo(VI), and Se(VI). The application of high-performance liquid chromatography (HPLC) showed that, when coupled to a refractive index detector, it is a rapid, sensitive, and accurate method for determining organic acids in soils. Three organic acids, acetic (2-20 mM), propionic (0-3 mM), and n-butyric (0-1.4 mM), were identified with HPLC and confirmed by gas chromatography in crop-residue-treated soils incubated under waterlogged conditions at 25C for 72 h. No organic acids were detected under aerobic conditions. Four mineral acids and 29 organic acids were studied for their effect on N mineralization and metal dissolution in soils incubated under waterlogged conditions at 30C for 10 days.

• Research Organization: Iowa State Univ. of Science and Technology, Ames, IA (United States)
• OSTI ID: 5608107
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
IOWA
LAND POLLUTION
METALS
DISSOLUTION
NITRATES
MINERALIZATION
SOILS
CONTAMINATION
ACETIC ACID
ALFALFA
ALUMINIUM
ARSENIC
BUTYRIC ACID
CADMIUM
CHROMIUM
COBALT
COPPER
GLYCINE HISPIDA
IRON
LEACHING
LEAD
LIQUID COLUMN CHROMATOGRAPHY
MAIZE
MANGANESE
MOLYBDENUM
NICKEL
PH VALUE
PROPIONIC ACID
SELENIUM
SILVER
TRACE AMOUNTS
TUNGSTEN
VANADIUM
ZINC
CARBOXYLIC ACIDS
CEREALS
CHROMATOGRAPHY
DEVELOPED COUNTRIES
ELEMENTS
FEDERAL REGION VII
GRAMINEAE
LEGUMINOSAE
LILIOPSIDA
MAGNOLIOPHYTA
MAGNOLIOPSIDA
MONOCARBOXYLIC ACIDS
NITROGEN COMPOUNDS
NORTH AMERICA
ORGANIC ACIDS
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PLANTS
POLLUTION
SEMIMETALS
SEPARATION PROCESSES
TRANSITION ELEMENTS
USA
540220* - Environment
Terrestrial- Chemicals Monitoring &amp; Transport- (1990-)