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Extraction of Organic Nitrogen and Ammonium From Soil with Hydrofluoric Acid
Author(s) -
Stevenson F. J.,
Kidder G.,
Tilo S. N.
Publication year - 1967
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1967.03615995003100010021x
Subject(s) - soil water , organic matter , clay minerals , chemistry , hydrofluoric acid , environmental chemistry , extraction (chemistry) , ammonium acetate , entisol , ammonium , mineralogy , soil science , geology , inorganic chemistry , organic chemistry , high performance liquid chromatography
From about one‐fifth to one‐half of the organic N in some surface soils, and over two‐thirds of that in some subsurface soils, occurred in compounds capable of being extracted with HF. The NH 4 + ‐N/organic N ratios in HF extracts were generally highest in soils where the predominant clay minerals were illitic, intermediate in soils where the predominant clay minerals were montmorillonitic, and lowest in soils where the clay fraction contained high amounts of amorphous (allophanic) material. The presence of organic N compounds within the lattice structures of clay minerals was indicated. Analyses of the Morrow Plot soils showed that a considerably higher fraction of the organic N in the heavily cropped soils was extractable with HF than in soils where organic matter had been maintained at high levels by periodic application of manure or through growth of legumes. Evidence was obtained in support of the view that many soils contain significant amounts of naturally occurring fixed NH 4 + .