1. Introduction
Land use change is an important factor in global change
phenomena. It is directly related to issues such as food
security, water quality, soil quality and other important global
life support issues [1]. Land use change and changes in soil
fertility management often occur together resulting changes
in soil quality including the activities of soil micro-organism
[2]. As a consequence, one would expect close relationships
between land use change and soil nutrient contents [3].
Land use change also affects the productivity of a soil.
This manifests as changes in soil properties such as contents
of available of macro and micro nutrient, organic matter and
CEC [4]. Agricultural sustainability requires periodic
evaluation of soil fertility status which is important in
understanding factors that impose serious constraints to crop
production under different land use types and for adoption of
suitable land management practices [5].
Land use change affect the distribution and supply of soil
nutrients by directly altering soil properties and influencing
biological transformations in rooting zone. For instance,
cultivation of forests diminishes the soil carbon within a few
years of initial conversion and substantially lowers mineral
stable of nitrogen [6]. Soil quality is a concept that integrates
soil biological, chemical and physical factors into a
framework for soil resource evaluation [7-9].
Soil properties such as water holding capacity, aeration,
tendency to crust, and cation exchange capacity can be
estimated from particle size distribution [10]. Differences in
soil texture also impacts organic matter levels which broke
down faster in sandy soils than in fine-textured soils this
gives similar environmental conditions and fertility
management because of a higher amount of oxygen available
for decomposition in the light-textured sandy soils. The
490 Lechisa Takele et al.: Dynamics of Soil Fertility as Influenced by Different Land Use Systems and Soil Depth in
West Showa Zone, Gindeberet District, Ethiopia
cation exchange capacity of the soil increases with percent
clay and organic matter and the pH buffering capacity of a
soil (its ability to resist pH change upon lime addition) is also
largely based on clay and organic matter content [11].
Soil chemical properties are the most important among the
factors that determine the nutrient supplying power of the
soil to the plants and microbes. The chemical reactions that
occur in the soil affects soil development and soil fertility
build up. Plants are capable of absorbing and assimilating as
many as forty or fifty different chemical elements. Sixteen of
these chemical elements have been found to be essential to
the growth of most plants. Therefore, this study was
conducted with specific objective to assess and explore the
status of soil physicochemical characteristics of three
different land use systems along soil depth of representative
area of Western Oromia Region. The result of this study
expected to add value to the up-to-date scientific
documentation of the status of soil fertility and soil quality of
different land uses of the study area and other similar agroecological
environments in the country.