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Chemical characteristics of humic acids from five soils in Kenya
Author(s) -
Arshad Muhammad A.,
Schnitzer Morris
Publication year - 1989
Publication title -
zeitschrift für pflanzenernährung und bodenkunde
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 87
eISSN - 1522-2624
pISSN - 0044-3263
DOI - 10.1002/jpln.19891520103
Subject(s) - soil water , arid , temperate climate , vegetation (pathology) , environmental chemistry , chemical composition , chemistry , environmental science , ecology , soil science , biology , organic chemistry , medicine , pathology
Humic acids (HAs) isolated from five soils (Luvisols, with 460–600 mm rainfall, Nitosols and Ferralsol, with 1060–1950 mm rainfall) from different ecological regions of Kenya were characterized by 13 C NMR and IR spectroscopy, elemental analyses and optical measurements. The data suggest that excessive rainfall in sub‐humid regions may lower the molecular weights of the HAs as well as their aromaticities. Concentrations of aliphatic components, including aminoacids and carbohydrates, in the HAs from the sub‐humid regions were higher (40–42 wt/wt %) than those in the HAs isolated from soils of the semi‐arid regions (29–32 wt/wt %). Chemical characteristics of the soils from the sub‐humid regions of Kenya resembled those of the HAs from temperate regions but differed from those of HAs originating from arid regions. Annual rainfall and vegetation appeared to affect the composition of HAs but effects of elevation and temperature were less clear.