BIOPHYSICAL CHARACTERISTICS AND LANDUSE/LANDCOVER CHANGES IN THE UPPER KUBANNI RIVER BASIN, KADUNA STATE, NIGERIA
BIOPHYSICAL CHARACTERISTICS AND LANDUSE/LANDCOVER CHANGES IN THE UPPER KUBANNI RIVER BASIN, KADUNA STATE, NIGERIA
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Date
2011-06
Authors
AYUBA, GRACE
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Abstract
The study is on Biophysical Characteristics and Landuse/landcover Changes in
the Upper Kubanni River Basin, Kaduna State, Nigeria. The objectives are
mainly to assess the local vegetation cover; evidence of firewood gathering and
grazing activities. Soil erosion and the spatial variation were also assessed as
well as the intensity of landuse/landcover changes and the significance of these
baseline data to water resource development in the Upper Kubanni Reservoir.
The data for local vegetation cover and soil characteristics were obtained
through field survey. Data on the vegetation cover was obtained using the
modified technique of Whittaker (1970). Two N-S transects were also
developed across the study area within which three quadrangles of 100m x100m
(10000sq meters) were sampled. Soil samples were collected from profile pits at
0 cm – 120cm depth. The soil samples taken from the pedogenic horizons of the
profiles were weighed and subjected to laboratory analysis particularly that of
the physical soil properties. Landuse/landcover changes over the years were
obtained from three sets of Land Sat imageries for the years 1987, 1994 and
2005. The results of the study showed evidence of vegetation degradation
characterized by few trees and are short statured. Beside the absence of
periodical grasses, the degradation was aided by the excessive wood harvesting,
cultivation and overgrazing activities on the basin. The soils of the study area as
shown from the results were mainly loamy in texture with preponderance of sand
fraction. And the aggregate stability index was relatively stable. But the soil bulk
density result of 1.53 mgm3 for a sandy loam soil is tending towards the
threshold. The landsat imagery showed that cultivation and grazing rank highest
in the landuse/landcover on the basin, while built up areas continued to rise.
Important to note also is the disappearance of natural open savanna vegetation
which was being replaced by shrub regrowth. Gully growth has been on the
increase. But a decrease in growth of gullies was observed in the year 2009,
which may not be unconnected to the tree planting exercise carried out by
Ahmadu Bello University. These results have implications on increasing
sediment yield into the Basin.
Description
A THESIS SUBMITTED TO THE POSTGRADUATE
SCHOOL,AHMADU BELLO UNIVERSITY,ZARIA, KADUNA STATE,
NIGERIA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS
FOR THE AWARD OF THE DEGREE OF MASTER OF SCIENCE IN
GEOGRAPHY
Keywords
BIOPHYSICAL,, CHARACTERISTICS,, LANDUSE/LANDCOVER,, CHANGES,, UPPER,, KUBANNI RIVER BASIN,, KADUNA STATE,, NIGERIA