Premium
MOLECULAR WEIGHT DISTRIBUTION OF SOIL ORGANIC MATTER AS AFFECTED BY ACID PRE‐TREATMENT AND FRACTIONATION INTO HUMIC AND FULVIC ACIDS
Author(s) -
GOH K. M.,
REID M. R.
Publication year - 1975
Publication title -
journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 0022-4588
DOI - 10.1111/j.1365-2389.1975.tb01944.x
Subject(s) - fractionation , chemistry , organic matter , soil water , humic acid , molar mass distribution , fulvic acid , environmental chemistry , precipitation , soil organic matter , chromatography , organic chemistry , soil science , geology , polymer , fertilizer , physics , meteorology
Summary Effects of acid pre‐treatment and fractionation on the molecular weight distribution of OIM Na 4 P 2 O 7 organic matter extracts were investigated in a chronosequence of weakly weathered soils developed on aeolian sand in New Zealand. Acid pre‐treatment of soils with OIM HCl followed by OIM HCI:03M HF was found to enhance the polydispersion in the nominal molecular weights of the extracts. The same treatment resulted in significant increases in yield and reduction in ash content. However, prolonged standing of extracts in the acids led to acid‐induced polymerization, resulting in a predominance of organic matter in the higher nominal molecular weight ranges. Fractionation of organic matter extracts by acid precipitation into humic and fulvic acids did not separate them according to molecular weight as commonly believed. Instead, fulvic acids from most soils were found to have similar nominal molecular weight distributions to those of their humic acid counterparts. A large proportion of soil fulvic acid compounds was in the > 100 000 nominal molecular weight range.