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Walkley‐Black Digestion Efficiency and Relationship to Loss on Ignition for Selected Sierra Leone Soils
Author(s) -
Rhodes E. R.,
Kamara P. Y.,
Sutton P. M.
Publication year - 1981
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/sssaj1981.03615995004500060024x
Subject(s) - loss on ignition , sierra leone , soil water , organic matter , total organic carbon , chemistry , combustion , soil organic matter , environmental chemistry , soil science , mineralogy , environmental science , organic chemistry , development economics , economics
Ten top soils sampled from six physiographic positions in the Njala Survey Area of Sierra Leone, West Africa, varied in organic carbon content from 1.02 to 7.82% and in clay content from 22 to 65%. Walkley‐Black oxidation efficlency ranged from 93 to 100% and averaged 97%, using Wet Combustion as standard. Organic matter in these tropical soils is apparently in forms easily oxidized by the sulphuric acid‐dichromate digestion. Simple correlation between organic carbon (C) and loss on ignition (L.O.I.) was very strong, r = 0.997; partial correlations showed that when organic C was held constant, 31% of the variation in L.O.I. was associated with clay content variation, and when clay content was held constant, 98% of the variation in L.O.I. was associated with organic C. Ignition loss of organic C was closely predicted by the linear relationship y = 0.505 x − 0.094, where x = % organic C. Prediction error (about 0.5%) was proportionately greater at lower levels of ignition loss.