Nitrogen Forms in Three Kenyan Soils Nitisols, Luvisols and Ferralsols
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Date
2016
Authors
Karukua, G.N
Mochoge, B.O
Journal Title
Journal ISSN
Volume Title
Publisher
International Educative Research Foundation and Publisher
Abstract
The nitrogen cycle in soil is an integral part of the overall cycle of N in nature. The primary source of N
is the atmosphere where the strongly bonded gas molecule N is predominately gas (78.08%). Total N
content in soils ranges from 0.02% in the subsoil and more than 2.5% in peats; ploughed layers of most
cultivated soils contain between 0.06 and 0.5%. The amount present in each case is, however determined
by climate, type of vegetation, topography, parent material and activities of man. Over 95% of TN in
surface soils is organically bound while the portion of non-exchangeable N is high in subsurface soil.
Knowledge concerning the nature of organic N in soils is based on studies involving identification and
estimation of N forms released by treatment with hot acids. Organic N forms were determined in three
soils by acid hydrolysis. The total hydrolysable organic N for the 0-15 and 15-30cm layers were 57.2 and
59.3% for Gituamba andosols; 56.9 and 61.9 for Kitale ferralsols; 39.0 and 42.1% for Katumani luvisols,
respectively. Amide N ranged from 11.6 to 21.4% of total N; Hexosamine from 5.2 to 10.1% and Amino
acid N from 26.2 to 37.1%. Amino acid N therefore formed the highest portion followed by Amide N of
the hydrolysable organic N.
Description
Article
Keywords
Nitrogen Forms in Three Kenyan Soils Nitisols, Luvisols and Ferralsols
Citation
Karuku, G. N., & Mochoge, B. O. (2016). Nitrogen forms in three Kenyan soils Nitisols, Luvisols and Ferralsols. International Journal for Innovation Education and Research, 4(10), 17-30.