ANALYSIS OF THE RELATIONSHIP BETWEEN SOIL PROPERTIES AND SOIL FORMING-FACTORS IN THE NIGERIAN SAVANNA
ANALYSIS OF THE RELATIONSHIP BETWEEN SOIL PROPERTIES AND SOIL FORMING-FACTORS IN THE NIGERIAN SAVANNA
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Date
1986-09
Authors
JAYEOBA, IDRIS AUDU
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Abstract
An examination of the status and the relationships
between key soil properties and the soil-forming factors
of climate, parent material and relief, under savanna
environment, form the primary objectives of this study.
The data used wore obtain mainly from the noral land resource survey covering; north central
nigeria.The survey was carried out by the Land Resoure Division, British Ministry of Overseas Development,
and covers an area of about 230,000km . Selection of
profiles from the survey data were based on their wide range
of characteristics, representative of soils within
particular geomcrphic units, and availability of information
on some of the soil-form in g factors considered, -»7hich arc
missing from the land resource survey data. All together,
385 pro files were selected.
The method of analysis of the spatial variability
of the soil properties cantered on the use of simple
line arregression analysis, in respect of factors with
interval data, and one-way analysis of variance for those
at normal level and also interval level,
following a preliminary conversion onto ordinal.
In nearly all the samples considered, tho paticle-size
distribution reveals the presence of a maximum of sand and
/ and
minima of silt/clay. On the whole, however, the subsoils
Sandy and more clayey than the top soils. The soilsare generally low in organic matter, total nitrogen, and
exchangeable base (K, Na, Mg & Oft) content except soils
formed from basalt and shale and over somo tasal slope
positions which have moro than average values, ..rcflecting
presumably the low organic matter and clay contents, the
CEC values are low and the soil reaction weakly to moderately
acid.
The soil structural units are predominantly moderately
dove loped but the soils themselves show little compaction
and are characterized by relatively high effective depth.
Stop by stop examination of individual soil properties
and the soil-forming factors reveals numerious .invariably
disperate relationships often explicable only in terms of
local conditions. However, by combining all the variables
involved in an analysis of variance and covariance, the
results seem to suggest that the variability of virtually
all the Soil properties considered, except the PH, |
' the fine sand subfraction which are mere strongly related
to the rainfall factor, are better explained in terms of the
material factor than in terns of the other factors.
Apart from being the major factor controlling the pH,
%BS and the fine sand, the rain fall factor is also,
important in the variability of most of the other properties,
particularly the organic total nitrogen, bulk
density and clay, and thus the CEC of the soils. The
organic carbon, fine sand, %BS show stronger.
correlation with altitude than the other properties. Slope
position is more important in the variability of the organic
carbon, total nitrogen, sand, clay, CEC, %BS and bulk
density than of the other properties-. By contrast, the
temperature and slope gradient factors play relatively
minor roles in the spatial variability of the soil
properties considered, except the soil effective depth
in respect of the second factor
Description
A THESIS SUBMITTED TO THE POSTGRADUATE SCHOOL, AHMADU
BELLO UNIVERSITY, ZARIA, IN PARTIAL FULFILMENT OF THE
REQUIREMENT FOR THE DEGREE OF DOCTOR OF PHILOSOPHY.
DEPARTMENT OF GEOGRAPHY
FACULTY OF SCIENCE
AHMADU BELLO UNIVERSITY
ZARIA
SEPTEMBER, 1986
Keywords
ANALYSIS,, RELATIONSHIP,, SOIL PROPERTIES,, SOIL FORMING-FACTORS,, NIGERIAN SAVANNA