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Impacts of Land Use Types on Selected Soil Physico-Chemical Properties of Loma Woreda, Dawuro Zone, Southern Ethiopia

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A study was conducted in Loma Woreda, Dawuro Zone, Southern Ethiopia, to investigate the impacts of land use types (forest, grazing and cultivated) on the selected soil physico chemical properties of the study area. Composite surface (0-20 cm) soil samples were collected randomly from three sites of each land use which were adjacent to each other and subjected to laboratory analysis. The results of the study revealed that there was relative variation in proportion of sand and clay content among the land use types though they have the same textural class. The bulk density of the soils decreased from grazing to cultivated and then to forest land, while total porosity decreased from forest to cultivated and then to grazing lands. The average soil pH-H 2 O value of the area varied from very strongly acidic to strongly acidic. Exchangeable acidity and Percent Acid Saturation were significantly lower by about 60.02 and 61.54% in the forest soils than the soils of cultivated lands, and 29.70 and 38.32% than that of grazing lands, respectively. As compared to the soils of forest land, the amount of soil OM, TN and CEC in cultivated land have declined by about 76.53, 60.83 and 38.97%, respectively. The available P, exchangeable bases and PBS have shown decreasing trends in the soils of forest to grazing and then to cultivated land uses. From this study, it can be concluded that the soil fertility and quality were well maintained relatively under the forest land, while the impact on most parameters were negative on the soils of the cultivated land. Applications of lime, organic and inorganic fertilizers and crop rotation especially in the cultivated lands may enhance the productivity of the soils, implying the need for undertaking integrated soil fertility management in sustainable way to improve and maintain the favorable soil properties.
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A Peer
-
reviewed
Official International Journal
Science,
Sci. Technol. Arts Res.
Impacts of Land Use Types on Selected Soil Physico
of Loma
Getahun Bore
1
College of Agriculture, WolaitaSodo University, P.O.
2
School of Natural Resources Management and Environmental Sciences,
Abstract
A study was conducted in Loma Woreda, Dawuro
impacts of land use types (forest, grazing and cultivated) on the selected soil physico
chemical properties of the study area. Composite surface (0
collected randomly from three sites of
each land use which were adjacent to each other and
subjected to laboratory analysis. The results of the study revealed that there was relative
variation in proportion of sand and clay content among the land use types though they have
the same textural cl
ass. The bulk density of the soils decreased from grazing to cultivated
and then to forest land, while total porosity decreased from forest to cultivated and then to
grazing lands. The average soil pH-H
2
O value of the area varied from very strongly acidic
strongly acidic. Exchangeable acidity and Percent Acid Saturation were significantly lower by
about 60.02 and 61.54% in the forest soils than the soils of cultivated lands, and 29.70 and
38.32% than that of grazing lands, respectively. As compared to th
amount of soil OM, TN and CEC in cultivated land have declined by about 76.53,
38.97%, respectively.
The available P, exchangeable bases and PBS have shown
decreasing trends in the soils of forest to grazing and then t
study, it can be concluded that the soil fertility and quality were well maintained relatively
under the forest land, while the impact on most parameters were negative on the soils of the
cultivated land. Applications of l
ime, organic and inorganic fertilizers and crop rotation
especially in the cultivated lands may enhance the productivity of the soils, implying the need
for undertaking integrated soil fertility management in sustainable way to improve and
maintain the favorable soil properties.
Copyright@201
5
STAR Journal
INTRODUCTION
Land use changes are regarded as important
components and a primary cause of global environmental
changes (Turner et al.
, 1995). These changes are driven
by the interaction in space and time between biophysical
and human dimensions (Turner, 1995). The rate
quality degradation depends on land use systems, soil
types, topography, and climatic conditions. Several works
showed that inappropriate land use aggravates the
degradation of soil physico-
chemical and biological
properties (Saikh et al., 1998b; He et al
., 1999). Changes
in land use and management practices often modify most
soil morphological, physical, chemical and biological
properties to the extent reflected in agricultural
productivity (Heluf and Wakene, 2006).
The conversion of native fore
st and native range land
into cultivated land is known to deteriorate soil properties
(Mulugeta et al., 2005; Eyayu et al.
, 2009; Nega and
Heluf, 2009). The authors reported increment of bulk
density, organic matter deterioration and reduction in
cation ex
change capacity (CEC), which in turn reduce the
Official International Journal
of Wollega University, Ethiopia
DOI:
http://dx.doi.org/10.4314/star.v4i4.
ISSN: 2226-7522 (Print) and 2305
-
Science,
Technology
and Arts Research Journal
Sci. Technol. Arts Res.
J., Oct-Dec
201
Journal Homepage:
http://www.starjournal.org/
Impacts of Land Use Types on Selected Soil Physico
-
Chemical Properties
Woreda
, Dawuro Zone, Southern Ethiopia
Getahun Bore
1*
and Bobe Bedadi
2
College of Agriculture, WolaitaSodo University, P.O.
Box: 138, Sodo, Ethiopia
School of Natural Resources Management and Environmental Sciences,
Haramaya University,
P.O. Box: 138, Dire Dawa, Ethiopia
Abstract
Article Information
A study was conducted in Loma Woreda, Dawuro
Zone, Southern Ethiopia, to investigate the
impacts of land use types (forest, grazing and cultivated) on the selected soil physico
-
chemical properties of the study area. Composite surface (0
-20 cm) soil samples were
each land use which were adjacent to each other and
subjected to laboratory analysis. The results of the study revealed that there was relative
variation in proportion of sand and clay content among the land use types though they have
ass. The bulk density of the soils decreased from grazing to cultivated
and then to forest land, while total porosity decreased from forest to cultivated and then to
O value of the area varied from very strongly acidic
to
strongly acidic. Exchangeable acidity and Percent Acid Saturation were significantly lower by
about 60.02 and 61.54% in the forest soils than the soils of cultivated lands, and 29.70 and
38.32% than that of grazing lands, respectively. As compared to th
e soils of forest land, the
amount of soil OM, TN and CEC in cultivated land have declined by about 76.53,
60.83 and
The available P, exchangeable bases and PBS have shown
decreasing trends in the soils of forest to grazing and then t
o cultivated land uses. From this
study, it can be concluded that the soil fertility and quality were well maintained relatively
under the forest land, while the impact on most parameters were negative on the soils of the
ime, organic and inorganic fertilizers and crop rotation
especially in the cultivated lands may enhance the productivity of the soils, implying the need
for undertaking integrated soil fertility management in sustainable way to improve and
Article History:
Received :
Revised :
Accepted
Keywords
Land use types
S
oil properties
Acidic soil
*Corresponding Author:
Getahun Bore
E-
mail:
getibore04@gmail.com
STAR Journal
, Wollega University
. All Rights Reserved.
Land use changes are regarded as important
components and a primary cause of global environmental
, 1995). These changes are driven
by the interaction in space and time between biophysical
and human dimensions (Turner, 1995). The rate
of soil
quality degradation depends on land use systems, soil
types, topography, and climatic conditions. Several works
showed that inappropriate land use aggravates the
chemical and biological
., 1999). Changes
in land use and management practices often modify most
soil morphological, physical, chemical and biological
properties to the extent reflected in agricultural
st and native range land
into cultivated land is known to deteriorate soil properties
, 2009; Nega and
Heluf, 2009). The authors reported increment of bulk
density, organic matter deterioration and reduction in
change capacity (CEC), which in turn reduce the
fertility status of the given soils, as main impacts. In
addition, change in land use, long term cultivation,
deforestation,
overgrazing and mineral fertilization can
cause significant variations in soil prop
reduction of output (Conant et al.,
2003).
Earlier studies by Agoume and Birang (2009) showed
that land use systems significantly affected the clay, t
silt and the sand fractions.
Sand and silt decreased with
the soil depth, whereas clay inc
reased with it. Soil pH,
total N, organic carbon, available P, exchangeable Ca,
exchangeable Al, sum of bases, effective cation exchange
capacity (ECEC) and Al saturation significantly differed
with the land use systems. Al saturation increased with
soil d
epth, and the top soils presented acidity problems
while the sub soils exhibited Al toxicity.
The soils of the study area have been continuously
cultivated and depleted. Although knowledge of soil
physical and chemical properties plays a vital role in
enh
ancing production and productivity on sustainable
Original Research
40
of Wollega University, Ethiopia
http://dx.doi.org/10.4314/star.v4i4.
6
-
3372 (Online)
and Arts Research Journal
201
5, 4(4): 40-48
http://www.starjournal.org/
Chemical Properties
Box: 138, Sodo, Ethiopia
Haramaya University,
Article Information
Article History:
Received :
04-10-2015
Revised :
22-12-2015
Accepted
: 25-12-2015
Keywords
:
Land use types
oil properties
Acidic soil
*Corresponding Author:
Getahun Bore
mail:
getibore04@gmail.com
fertility status of the given soils, as main impacts. In
addition, change in land use, long term cultivation,
overgrazing and mineral fertilization can
cause significant variations in soil prop
erties and
2003).
Earlier studies by Agoume and Birang (2009) showed
that land use systems significantly affected the clay, t
he
Sand and silt decreased with
reased with it. Soil pH,
total N, organic carbon, available P, exchangeable Ca,
exchangeable Al, sum of bases, effective cation exchange
capacity (ECEC) and Al saturation significantly differed
with the land use systems. Al saturation increased with
epth, and the top soils presented acidity problems
while the sub soils exhibited Al toxicity.
The soils of the study area have been continuously
cultivated and depleted. Although knowledge of soil
physical and chemical properties plays a vital role in
ancing production and productivity on sustainable
Original Research
Getahun Bore and Bode Bedadi Sci. Technol. Arts Res. J., Oct-Dec 2015, 4(4): 40-48
41
0.0
5.0
10.0
15.0
20.0
25.0
0.0
50.0
100.0
150.0
200.0
250.0
300.0
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Monthly Total RF (mm)
Mean Max. Temp (◦c)
Mean Min Temp (◦c)
Mean Monthly
Total RF (mm)
Mean Max. and
Min. Temp. (◦c)
basis, there is limitation of knowledge and detail
information on the characteristic features of soils around
study area of Loma Woreda, Southern Ethiopia. Thus, this
study was to investigate the impacts of different land use
types (forest, grazing and cultivated) on the selected soil
physico-chemical propertiesof the study area. The
findings of the study are expected to contribute to the
improvement of the productivity of the acidic soils and to
fill-in the knowledge gap in soil acidity management
problems in the study area.
MATERIALS AND METHODS
Description of the Study Area
Location, Climate and Soil
The study was conducted in Loma Woreda, Dawuro
Zone of Southern Nations, Nationalities and People's
Regional State (SNNPRS), Ethiopia. Geographically, the
study area lies between 6°54′29.96'' to 6°55′16.78″ N and
37°13'49.10'′ to 37°14'18.05'' E. It is at about 500 km
south west of Addis Ababa, the capital of Ethiopia (Figure
1). The study area lies between 2286 and 2516 masl
receiving a total annual rainfall range from 1355.4 to
2565.6 mm with mean monthly temperature varying from
11.7 to 23.5
°
C. The rainfall is a bimodal type: the short
rainy season is between March and May, and the long
between June and September (Figure 2). According to
Tefera et al. (1999), the geology of the study area is
abundant with rhyolites and trachy basalts mainly
overlying in the Precambrian basement and tertiary
volcanism. Most of the area is mountainous, having well
drained and moderately weathered brown soil (Nitisols)
and Orthic Acrisols (BoPED, 1998).
Figure 1: Location map of the study area
Figure 2: Mean monthly minimum and maximum temperatures (
0
C) and mean monthly total rainfall (mm) of the study
area recorded for the year from 1999-2010 (Source: National Meteorological Agency; Gessachare station)
(A) (B) (C)
Figure 3: Photos of land use types in the study area; A = Cultivated land, B = Grazing Land, and C = Forest land
Getahun Bore and Bode Bedadi Sci. Technol. Arts Res. J., Oct-Dec 2015, 4(4): 40-48
42
Land Use and Farming Systems
Cultivated land uses are areas cultivated for annual
crops production. These areas contain very few scattered
trees deliberately left as traditional agro-forestry trees.
The problem of cultivated lands on the study areas are
being on steeper slopes and losing their depth and fertility
due mismanagement. The grazing land uses include
areas comprising of private lands with little or no
vegetations which are used for livestock grazing and
brewing purpose. Forest land use considered in the study
are areas covered with long and dense trees with dense
indigenous natural forest. It is under constant pressure
due to the expansion of agricultural lands. The natural
vegetation is shrunk near the bottom of high mountains,
course of rivers and around the churches.
The dominant vegetations grown in the study areas
include Arundinaria alpina, Erythrina brucei, Eucalyptus
spp., Juniper procera, Maesa lanceolata, Vernonia
theophrasti folia, Cordia africana, Croton macrostachyus
and others. The farming system of the area is
predominantly subsistence farming based on mixed crop-
livestock production.
The dominant crops grown in the study area include
legume crops (faba bean, lentil and field peas), cereal
crops (wheat, rye, barley, maize), perennial crops such as
Enset (Ensete ventricosum L.), coffee, different agro-
forestry tree species and eucalyptus plantations and root
crops (potatoes and taro) and others. Enset is the source
of the staple food in the area which provides vegetation
cover and creates green scenery. The scattered trees in
the cultivated lands are preserved from the original forest
during clearance, which are indicator of previously
existing forest in that area (LWADO, 2013; Mathewos et
al., 2013).
Site Selection and Soil Sampling for Laboratory
Analysis
A preliminary survey and field observation was carried
out to generate key information regarding the land forms,
land uses, topography and vegetation cover of the study
sites. Accordingly, three major representative land use
types (forest, grazing and cultivated lands) of the study
area, which are adjacent to each other, were identified.
Undisturbed core and disturbed composite surface (0-20
cm) soil samples were collected randomly from each land
uses, replicated three times and subjected to laboratory
analysis. Eighteen to twenty three sub-samples were
augured following the ‘zigzag’ pattern and mixed
thoroughly to make composite samples according to
variations on their drainage, slope gradient, vegetation
cover, management practices, soil color, history and
occurrence at different landscape positions. Analysis of
soil samples was carried out at the Haramaya University
Soil Chemistry Laboratory.
Laboratory Analysis of Soil Samples
Soil pH was measured potentiometrically with a digital
pH meter in the supernatant suspension of 1:2.5 soils to
water ratio (Barauah and Barthakulh, 1997). Particle size
and bulk density were determined following Bouyoucos
hydrometer (Day, 1965) and core sampling (Jamison et
al., 1950) methods, respectively. Average particle density
(PD) of mineral soil (2.65 g cm
-3
) and bulk density were
used to estimate total porosity as described as follows:
Total porosity (%) = (1 − 


) ∗ 100; Where BD = bulk
density in (g cm
-3
) and PD = particle density (g cm
-3
)
Soil organic carbon was determined by dichromate
oxidation method (Walkely and Black, 1934) and organic
matter content was computed from organic carbon
content by multiplying the latter by 1.724. Total Nitrogen
was determined using the micro-Kjeldahl digestion,
distillation and titration procedure as described by
Bremner and Mulvaney (1982). Available phosphorus was
extracted by the Bray-II method (Bray and Kurtz, 1945)
and quantified using spectrophotometer (wave length of
880 nm) colorimetrically using vanado molybdate as an
indicator.
Exchangeable basic ions (Ca, Mg, K and Na) were
extracted using 1 M ammonium acetate (NH
4
OAc)
solution at pH 7. The extracts of Ca and Mg ions were
determined using AAS while K and Na were determined
by flame photometer. To determine the cation exchange
capacity (CEC), the soil samples was first leached with 1
M NH
4
OAc, washed with ethanol and the adsorbed
ammonium was replaced by sodium (Chapman, 1965).
The CEC was then measured titrimetrically by distillation
of ammonia that was displaced by Na following the micro-
Kjeldahl procedure. Total exchangeable acidity was
determined by saturating the soil samples with 1 M KCl
solution and titrating with 0.02 MHCl as described by
Rowell (1994). From the same extract, exchangeable Al in
the soil was determined by titrating with a standard
solution of 0.02 M HCl. The soil percent base saturation
(PBS) was calculated from sum of the basic
exchangeable cations (Ca, Mg, K and Na) as the
percentage of CEC.
Data Analysis
Data recorded were subjected to analysis of variance
(General Linear Model (GLM) procedure) using SAS
software version 9.1 (SAS Institute, 2004) to test
differences in selected soil physical and chemical
properties among the different land use. Least Significant
Difference (LSD) (p≤0.05) test was used to separate
statistically significant means of soil parameters.
Correlation analyses were also carried out to detect the
magnitude and degree of relationships among key soil
variables.
RESULTS AND DISCUSSION
Selected Soil Physical Properties under Different
Land Use Types
Particle Size Distribution
The Analysis of variance indicated that silt content was
not significantly (P≤0.01) affected by land uses (Table 2).
However, the least significant difference (LSD) (p≤0.05)
test showed that the mean values of sand and clay
contents were statistically significantly affected by land
use types. Generally, the overall textural class of the soils
under the different land use types is found to be clay
loam, which may indicate the similarity in parent material
(Table 1).
A relative variation in proportion of clay and sand
content in the cultivated land could be due to soil erosion,
because most of the cultivated fields in the study area
lacks soil and water conservation measures as well as
management practices, which might have resulted in
removal of a smallest soil separates of clay that are easily
transported by either water or wind erosion. In agreement
with this Teshome et al. (2013) indicated the reason for
Getahun Bore and Bode Bedadi Sci. Technol. Arts Res. J., Oct-Dec 2015, 4(4): 40-48
43
low clay in surface layers of cultivated lands might be due
to selective removal of clay from the surface by erosion.
Similarly, Achalu et al. (2012) reported that soils of
different land use systems, but of same area with same
soil type and textural class, differed in some other soil
physical conditions mainly due to the fact that soil physical
properties change with the change in land use systems
and its management practices.
Table 1: Effects of land use types on selected physical properties of surface soil (0-20 cm) of the study area
Land Use
Types
Soil Physical Properties
Sand Silt Clay Soil Class Bulk Density (gcm
-
3
) Total Porosity (%)
Forest 24.33
b
33.78
41.89
a
Clay Loam 1.07
c
59.63
a
Grazing 25.67
b
35.00
39.33
a
Clay Loam 1.36
a
48.69
c
Cultivated 31.67
a
34.56
33.77
b
Clay Loam 1.15
b
56.61
b
LSD(0.05) 1.99 3.83 3.16 - 0.03 1.15
CV (%) 3.67 5.57 4.12 - 1.28 1.05
*Means within a column followed by the same letter are not significantly different at p0.05;
LSD = Least Significant Difference, CV = Coefficient of Variation
Table 2: Analysis of variance (ANOVA) results of soils of study area under three land use types (forest, grazing and
cultivated land)
Soil property DF SS MS EMS F-value P >F
Sand (%) 2 91.55 45.77 1.00 45.78 0.0002
Silt (%) 2 2.30 1.15 3.68 0.31 0.743
Clay (%) 2 103.23 51.61 2.50 20.62 0.0002
Bulk Density (gcm
-
3
) 2 0.134 0.06 NS 288.43 ≤0.0001
Total Porosity (%) 2 191.53 95.76 0.33 289.64 ≤0.0001
pH-H
2
O 2 0.44 0.22 0.008 30.49 0.0001
Exchangeable Aluminum(cmol
(+)
kg
-
1
) 2 47.39 23.69 0.14 159.14 ≤0.0001
Exchangeable Acidity(cmol
(+)
kg
-
1
) 2 53.28 26.64 0.13 198.57 ≤0.0001
Available Phosphorous(ppm) 2 38.02 19.01 0.92 20.48 0.0002
Organic Matter (%) 2 47.42 23.71 0.008 2819.91 ≤0.0001
Total Nitrogen (%) 2 0.04 0.02 NS 151.9 ≤0.0001
Carbon to Nitrogen Ratio 2 77.63 38.81 0.66 58.97 0.0001
ExchangeableCalcium (cmol
(+)
kg
-
1
) 2 16.96 8.48 0.08 103.82 ≤0.0001
Exchangeable Magnesium(cmol
(+)
kg
-
1
) 2 12.50 6.25 0.09 66.35 ≤0.0001
Exchangeable Potassium(cmol
(+)
kg
-
1
) 2 0.13 0.06 0.002 31.89 0.0001
Exchangeable Sodium(cmol
(+)
kg
-
1
) 2 0.105 0.05 0.001 27.38 0.0001
Cation Exchange Capacity (cmol
(+)
kg
-
1
) 2 213.68 106.84 0.93 114.20 ≤0.0001
Percent Acid Saturation (%) 2 2742.75 1371.37 6.83 200.55 ≤0.0001
Percent Base Saturation (%) 2 273.26 136.63 8.99 15.19 0.0005
*DF = Degree of Freedom, SS = Sum Square, MS = Mean Square = EMS = Error Mean Square, F Value = F calculated Value, P r= Probability
Bulk Density
As compared to the usual bulk density of mineral soils
suggested by Pam (2007),the mean value of surface (0-
20 cm) soil bulk density of the area was low for soils of
forest and cultivated land while moderate for soils of
grazing land. The LSD (p≤0.05) test also revealed that the
mean value of soil bulk density was statistically
significantly influenced by land use types. The mean value
of bulk density of the soils of grazing and cultivated land
increased by 27.1% and 19.62%, respectively from the
soils of adjacent forest land (Table 1).
The observed lowest bulk density value in forest land
soils is largely due to its relatively highest soil OM content,
as it holds high proportion of pore space to solids, which
as a result lowered bulk density. In line with this, the
overall bulk density showed negative but not significant
correlation (r = -0.32) with soil OM (Table 6). The practice
of ploughing in cultivated soil also tends to lower the
quantity of its OM. The continuous exposure of the soil
surface to the direct impact of rain drops under fields with
long period of continuous cultivation might have also
contributed to the increment of bulk density as raindrop
impacts cause soil compaction through disintegration of
the soil structure.
The observed relatively high bulk density value of the
grazing land soil could also be due to compaction
resulting from animal trafficking and large sand
proportions. The findings of the present study are in line
with the findings of Nega (2006) and Solomon et al.
(2002). Similarly, Eyayu et al. (2009) stated that the bulk
density in grazing and cultivated lands increased by 15.5
and 10.7%, respectively, in relative to the natural forest.
Total Porosity
The mean total porosities recorded for all the
considered land use types were classified as very high for
the study area in general according to the rating of FAO
(2006). The least significant difference (LSD; p≤0.05) test
has shown significant differences in total porosity among
the land use types (Table 1).
Highest soil mean total porosity under the soils of
forest land use type may be attributed to the relatively
lower animal trampling while lowest porosity is the result
of higher animal tracking in the soils of grazing land use.A
decline in total porosity in the soils of grazing and
cultivated land as compared to soils of forest land were
attributed to a reduction in pore size distribution and it is
Getahun Bore and Bode Bedadi Sci. Technol. Arts Res. J., Oct-Dec 2015, 4(4): 40-48
44
also closely related to the magnitude of SOM loss which
depending on the intensity of soil management practices
(Ogunkunle and Eghaghara, 1992; Achalu et al., 2012).
Selected Soil Chemical Properties under Different
Land Use Types
Soil pH
The average surface soil (0-20 cm) pH-H
2
O value of
the area was low and classified as strongly acidic as per
the pH rating category suggested by Tekalign (1991). As
indicated in Table 3, the acidic nature with low soil pH
obtained from all land use types may be attributed to the
leaching of basic cations (Ca Mg, K and Na) from the
surface soil since the area receives high rainfall. It was
observed that soil pH was significantly affected by land
use types (P≤0.01) (Table 2).
Table 3: Effects of land use types on pH-H
2
O, Exchangeable Acidity, Exchangeable Al and PAS of the surface soil (0-20
cm) in the study area
Land Use
Types
pH-H
2
O
(1:2.5)
Exch. Ac
(cmol
(+)
kg
-1
)
Exch. Al
(cmol
(+)
kg
-1
)
PAS
(%)
Forest 5.11
a
3.97c 3.41
c
26.51
c
Grazing 4.86
b
6.98
b
6.31
b
42.98
b
Cultivated 4.60
c
9.93
a
9.03
a
68.92
a
LSD(0.05) 0.11 0.73 0.77 5.22
CV (%) 1.14 5.26 6.17 5.66
*Means within a column followed by the same letter are not significantly
different at p0.05; Exch. Ac = Exchangeable Acidity, Exch.
Al = Exchangeable Aluminum, PAS = Percent Acid Saturation
The observed relatively higher pH in forest land soils
could be associated with higher OM content as it can bind
tightly Al ions and reduce their activity in the soil solution
and thereby increase pH and reduce acidity. Pearson’s
simple correlation analysis has also showed strong
positive correlation (r = 0.97
**
) between soil pH and soil
OM (Table 6). In connection with this, Abreha et al. (2012)
reported that the significantly high pH of soils from the
forest land might be attributed to the ameliorating effect of
the high accumulation of OM at surface. The same
authors indicated that the ameliorating effect of soil OM
could be due to the combined effect of the continuous
releasing of basic cations from the slow decomposition
rate of the accumulated OM in that cool humid area,
deposition of basic cations at the surface by the relatively
deep root forest trees from the subsoil and the specific
adsorption of organic anions on hydrous Fe and Al
surfaces and the corresponding release of hydroxyl ions.
The lower pH in soils of the cultivated land could be
attributed to the removal of basic cations by harvested
crops, more removal of basic cations by surface runoff
and deep percolation in cultivated land because of less
plant cover in cultivated land as compared to other land
uses. Likewise, it is reported that although acidity is
naturally occurring, agricultural practices such as the
removal of plant residues carrying organic anions and
excess cations from the farm or paddock are likely to
accelerate soil acidification (Schumann and Glover, 1999;
Nanthi and Mike, 2003).
Exchangeable Acidity and Aluminum, and Percent
Acid Saturation
The LSD (P≤0.05) test has revealed that there was
highly significant difference in exchangeable acidity and
exchangeable Al among the soils of all the considered
land uses. Exchangeable acidity was significantly lower by
about 60.02 and 29.70% in the forest land soils as
compared to the soils of adjacent cultivated and grazing
lands, respectively (Table 3).
The high soil exchangeable acidity in the cultivated
and grazing lands might be associated with the
occurrence of lower soil pH in both land use types. The
observed high exchangeable acidity and Al
3+
in the soils
of cultivated land uses were due in part to plant uptake of
Ca
2+
and in part to mixing up with soil to lower depth
through tillage, ploughing and losses through leaching. In
connection with this, correlation analysis has showed
strong negative correlation (r = -0.98
**
) between
exchangeable acidity and soil pH (Table 6). Reports also
indicated that exchangeable acidity is a function of soil pH
composed of compounds such as Al(OH)
2+
or Al(OH)
2+
,
and weak organic acid ions held at the colloidal surfaces
of the soil (Matzher et al., 1998; Hinrich et al., 2001).
The decrease in exchangeable Al and Al saturation in
the soils of forest land caused by increased pH and/or
complexation of Al by solid-phase OM that will favor a
reduction in Al concentrations in soil solution. Pearson’s
simple correlation analysis has showed strong positive
correlation of exchangeable acidity with PAS (r = 0.98
**
)
while strong negative correlation with PBS(r = -0.87
**
)
(Table 6). The inverse relationship of exchangeable
acidity and PAS with PBS could be due to deforestation
and intensive cultivation, which leads to the higher
exchangeable acidity content in soils of cultivated lands
than the other two adjacent land uses (Baligar et al.,
1997; Achalu et al., 2012).
Organic Matter Content
The OM contents of the soils in forest, grazing and
cultivated land use types were rated as very high, high
and low as per the rating of Murphy (1968). As compared
to the soil of forest land, the amount of soil OM in grazing
and cultivated land has depleted by 42.56 and 76.53%,
respectively (Table 4).Similarly, ANOVA revealed that soil
OM contents under the various land use types were
significantly (P≤0.01) (Table 2).Significantly higher
quantity of OM in forest land soilis mainly due to the
addition of more plant residues on its surfaces and their
reduced rate of disturbance as compared to the other land
use types.
Getahun Bore and Bode Bedadi Sci. Technol. Arts Res. J., Oct-Dec 2015, 4(4): 40-48
45
Table 4: Effects of land use types on soil OM, TN, C: N, and Available P of the surface soil (0-20 cm) in the study area
Land Use
Types OM (%) TN (%) C:N Av. P
(ppm)
Forest 7.33
a
0.263
a
16.14
a
10.18
a
Grazing 4.21
b
0.154
b
15.94
a
6.95
b
Cultivated 1.72
c
0.103
c
9.81
b
5.22
b
LSD(0.05) 0.18 0.02 1.62 1.92
CV (%) 2.07 6.64 5.81 12.92
*Means within a column followed by the same letter are not significantly
different at p0.05; OC = Organic Carbon, OM = Organic Matter,
C:N = Carbon to Nitrogen Ratio, Av. P = Available Phosphorous
Table 5: Effects of land use types on exchangeable bases (Ca, Mg, K, and Na), CEC and PBS of the surface soil (0-20
cm) in the study area
Land Use Types Exch. Ca Exch. Mg Exch. K Exch. Na CEC PBS
------------------------(cmol
(+)
kg
-
1
)----------------------------- ----(%)----
Forest 5.82
a
4.26
a
0.51
a
0.45
a
29.76
a
37.26
a
Grazing 5.22
b
3.30
b
0.38
b
0.34
b
26.40
b
35.07
a
Cultivated 2.66
c
1.42
c
0.20
c
0.19
c
18.16
c
24.63
b
LSD(0.05) 0.57 0.61 0.09 0.08 1.93 5.99
CV (%) 6.25 10.24 12.72 13.28 3.90 9.27
*Means within a column followed by the same letter are not significantly different at
p0.05; Exch. Ca = Exchangeable Calcium, Exch. Mg = Exchangeable Magnesium,
Exch. K = Exchangeable Potassium, Exch. Na = Exchangeable Sodium,
CEC = Cation Exchange Capacity, PAS = Percent Acid Saturation,
PBS = Percent Base Saturation, LSD = Least Significant Difference, CV = Coefficient of Variation.
Table 6: Pearson`s Correlation coefficient (r) among selected soil physicochemical properties
*
= significant at p≤0.05 and
**
= significant at p≤0.001; BD = Bulk Density, Av. P = Available Phosphorous, CEC = Cation Exchange
Capacity, EA = Exchangeable Acidity, EAl = Exchangeable Aluminum, TN = Total Nitrogen, OM = Organic Matter, PAS = Percent Acid
Saturation, PBS = Percent Base Saturation
The lower OM content in cultivated and grazing land
soil is attributed to anthropogenic factors like reduced
biomass return and livestock grazing. Coupled with this,
the well-drained conditions of the soils of the study area
enhanced the rate of OM decomposition. In line with this,
the findings of other works at different areas revealed that
the low OM content in soils of cultivated land could be
attributed to increased rates of mineralization of OM
mainly caused by tillage activities; the decline in total OM
inputs such as litter, crop residues and manures;
increased soil temperatures due to exposure of the soil
surface and increased wetting and drying cycles and the
loss by soil erosion (Chroth et al., 2003; Abreha et al.,
2012).
Reduced soil disturbance in the grazing land soils has
apparently led to an increase in OM content as compared
to soils in cultivated land use. Though absence of such
soil disturbance minimized rapid loss of soil OM, removal
of nutrients and low biomass return after grazing have led
to its decrease compared to the OM content observed in
forest land soils. This is may be partly due to the
continuous accumulation of un-decayed and partially
decomposed plant residues in the surface soils of forest
land use. Generally, forest clearing followed by
Getahun Bore and Bode Bedadi Sci. Technol. Arts Res. J., Oct-Dec 2015, 4(4): 40-48
46
conversion into grazing and agricultural land uses in
tropical ecosystems brought about remarkable decline of
the soil OM stock (Nega, 2006; Achalu et al., 2012).
Total N and Carbon to Nitrogen Ratios
Total N has showed significant variation among the
different land use types (Table 4) and rated as low,
medium and high for cultivated, grazing and forest land
soils, respectively, as per the rating of Berhanu (1980)
and Tekalign (1991). The depletion of total N in grazing
and cultivated land was 41.44 and 60.83%, respectively,
as compared to that of the soils of adjacent forest land
use. Analysis of variance also indicated that there is
significant (P≤0.01) difference in total N among the
considered land use types (Table 2). An addition of a
relatively higher plant residue and minimal rate of
decomposition might have contributed to higher amount of
total N in forest land soil. In agreement with this
correlation analysis has showed strong positive
correlation of total N (r=0.98
**
) with soil OM (Table 6).
The considerably large losses of total N in the
cultivated land could be attributed to rapid mineralization
of soil OM following cultivation, which disrupts soil
aggregates, and thereby increases aeration and microbial
accessibility to OM. Reduced input into the soils of plant
residues in such cereal based farming also has
contributed to the depletion of soil OM thereby soil N in
these cultivated soils. As the area receives high rainfall,
the N leaching problem can be another reason for the
decline of total N in soils of cultivated land. Nitrate ions
which are not adsorbed by the negatively charged colloids
that dominate most soils, therefore move downward with
drainage water and are thus readily leached from the soil
(Solomon et al., 2002; Yihenew and Getachew, 2013).
The mean comparison test revealed that the soils in
the cultivated land varied significantly in terms of C: N
from the soils of forest and grazing land use types
(p≤0.05) (Table 4).The lower C: N ratio in cultivated land
use compared to grazing and forest land uses could be
attributed to lower level of OM content. In line with this,
correlation analysis has also shown strong positive
correlation (r = 82
*
) of C: N with OM (Table 6). Relative to
forest land, soils of the cultivated land recorded narrow C:
N ratio could be probably due to aeration during tillage
and increased temperature that enhance higher microbial
activity and more CO
2
evolution and its loss to the
atmosphere from the top (0-20 cm) soil layer resulted to
the narrow C: N ratio (Abbasi et al., 2007; Achalu et al.,
2012).
Available Phosphorus
The mean available soil P contents were very low for
grazing and cultivated lands and low for forest land soil as
per the rating suggested by Jones (2003).In soils of the
forest land available soil P was significantly higher by
about 46.47 and 95.01% as compared to that of grazing
and cultivated land soils, respectively(Table 4).
The very low available P status in the cultivated and
grazing land soils could be associated with the low pH
and high exchangeable acidity. Hence, these soils with
relatively high exchangeable acidity can have the acidic
cations such as exchangeable Al, H, and oxides of Al and
Fe that could fix the soluble P in the soil solution. In
connection with this correlation analysis has showed
strong positive correlation (r = 0.86
*
) of available P with
soil pH but strong negative correlation (r = -0.90
*
) with soil
exchangeable acidity (Table 6). In line with this, Tekalign
and Haque (1987) and Dawit et al. (2002) reported SOM
as the main source of available P and the availability of P
in most soils of Ethiopia decline by the impacts of fixation,
abundant crop harvest and erosion.
Exchangeable Bases, CEC and PBS
As per the ratings of FAO (2006), the exchangeable
Ca, K and Na contents were medium in the soils of forest
and grazing land uses and low in the soil of cultivated land
use, whereas exchangeable Mg is high in soils of forest
and grazing land use types and medium in the soils of
cultivated land use (Table 5).
Compared to cultivated land the relatively higher
concentrations of exchangeable Ca, Mg, K and Na
contents recorded in soils of forest land could be due to
their continuous losses in the harvested parts of plants
(both grain and straw) and leaching of basic cations from
top soils of cultivated land. As one move from forest to
agricultural soils, the exchangeable bases readily
decreased showing the declining dominance of basic
cations in the exchange complex of the soil colloids and
this result is in agreement with the findings of Saikh
(1998a) and Jaiyeoba (2003). Similarly, He et al. (1999)
reported that domination of soil by extractable Al
3+
and
Fe
2+
ions as well as adsorption of the cations by higher
content of clay in the top soils of cultivated land resulted in
relatively lower contents of Ca and Mg ions in the soil.
The relatively lower concentration of exchangeable K
and Na contents in the cultivated and grazing lands than
in the forest land might be due to the same reason
explained for Ca and Mg ions. Variations in the
distribution of exchangeable bases depends on the
mineral present, particle size distribution, degree of
weathering, soil management practices, climatic
conditions, degree of soil development, the intensity of
cultivation and the parent material from which the soil is
formed (Heluf and Wakene, 2006). Generally, the
exchangeable base contents were well maintained in the
forest ecosystem due to nutrient recycling when
compared to grazing and cultivated lands, where basic
nutrients loss upon grazing and harvesting prevailed. The
exchange complex was dominated by Ca followed by Mg,
K and Na, indicating productive agricultural soils (Bohn et
al., 2001).
The observed reductions in the mean soil CEC values
of the considered land use types due to conversion of
forest lands into grazing and cultivated lands accounts
11.29 and 38.97%, respectively, in surface soils of the
study area (Table 5). The mean CEC values are rated as
high for forest and grazing land soils and medium for
cultivated land soils as suggested by Landon (1991).
The soil CEC values in the cultivated land uses
decreased mainly due to the reduction in OM content. In
agreement with this correlation analysis has showed
strong positive correlation (r = 0.88
*
) of CEC with soil OM
(Table 6).The findings of the present study concur with the
work of Woldeamlak and Stroosnijder (2003) who
reported highest CEC value in soils of forest land and
lowest under cultivated land. Basically, CEC of soil is
determined by the relative amounts and/or type of the two
main colloidal substances; humus and clay. Organic
matter particularly plays important role in exchange
Getahun Bore and Bode Bedadi Sci. Technol. Arts Res. J., Oct-Dec 2015, 4(4): 40-48
47
process because it provides more negatively charged
surfaces than clay particles do. On the other hand, the
decrease in CEC with pH can be attributed to a decline in
CEC values as pH-dependent charge (Johnson, 2002).
The PBS of the top soils (0-20 cm) was classified as
low status as per the ratings recommended by Pam
(2007). According to the same authors based on PBS as
a criterion of leaching, cultivated lands of the study area
are strongly leached while those of forest and grazing
lands are moderately leached. The trends of the
distribution of PBS showed similarity with the distribution
of CEC, exchangeable Ca and Mg, since factors that
affect these soil attributes also affect the PBS (Achaluet
al., 2012). The findings of this work indicated that
exchangeable bases, especially Ca and Mg ions dominate
the exchange sites of most soils and contributed higher to
the PBS which is also in agreement with Eyelachew
(1999).
CONCLUSIONS
It was obvious that conversion of land use systems
from natural forest to other land use systems would have
detrimental effect on soil physical and chemical
properties. Coupled with high population pressure,
practices like deforestation, overgrazing and intensive
cultivation of soils with low inputs in the present study
area may have resulted in disturbances, differences and
even deteriorations of soil properties among the
considered land use types.
The study has revealed that most of the soil physical
and chemical properties showed significant changes
associated with forest clearing. There are high risks to the
sustainable crop production and soil fertility in cultivated
lands of the study area which is highly nutrient depleted.
This might be due to continuous intensive cultivation,
overgrazing, erosion and removal of crops and crop
residues with poor soil management practices. Therefore,
best integrated land management practices, like liming,
returning crop residues to the fields and integrated use of
organic and inorganic fertilizers are very crucial and
should be given special attention to increase the essential
soil basic nutrients and increase soil pH of these acidic
soils to the desired level for sustainable natural vegetation
management, crop production and to recover intensively
cultivated degraded lands.
Acknowledgements
The authors are grateful to the financial grant of the
Ministry of Education through the Haramaya University.
We also acknowledge the staff members and laboratory
technicians of Haramaya University for their cooperation
and technical help during analysis of soil samples.
Conflict of Interest
Conflict of interest none declared.
REFERENCES
Abbasi, M.K., Zafar, M., and Khan, S.R. (2007). Influence of
different land-cover types on the changes of selected soil
properties in the mountain region of Rawalakot Azad
Jammu & Kashmir. Nutrient Cycling in Agroecosystems
78: 97-110.
Abreha Kidanemariam, Heluf Gebrekidan, Tekalign Mamo
and Kindie Tesfaye (2012). Impact of Altitude and Land
Use Type on Some Physical and Chemical Properties of
Acidic Soils in Tsegede Highlands, Northern
Ethiopia.Open Journal of Soil Science, 2: 223-233
Achalu Chimdi, Heluf Gebrekidan, Kibebew Kibret and Abi
Tadesse (2012). Status of selected physicochemical
properties of soils under different land use systems of
Western Oromia, Ethiopia. Journal of Biodiversity and
Environmental Sciences 2(3): 57-71.
Agoume, V., and Birang, A.M., (2009). Impact of Land Use
Systems on some Physical and Chemical Soil Properties
of an Oxisol in the Humid Forest Zone of Southern
Cameroon.Tropicultura 27(1): 15-20.
Baligar, V.C., Pitta, G.V.E., Gamma, E.E.G., Schafter, R.E.,
Filho, A.F., and Clark, R.B. (1997). Soil acidity effects on
nutrient use efficiency in exotic maize genotypes. Plant
and Soil 192:9-13.
Barauah, T.C. and H.P. Barthakulh (1997). A Text Book of
Soil Analyses.Vikas Publishing House Pvt. Ltd. New
Delhi, India.
Berhanu Debele (1980). The physical criteria and their rating
proposed for land evaluation in the highland region of
Ethiopia. Land Use Planning and Regulatory Department,
Ministry of Agriculture, Addis Ababa, Ethiopia.
Bohn, H., Mcneal, B.L. and O’connor, G.A. (2001). Soil
Chemistry. 3
rd
ed. John Wiley and Sons, INC, pp.207-233.
BoPED (Bureau of Planning and Economic Development),
(1998). Regional Atlas of SNNPRS, BoPED, Awassa,
Ethiopia.
Bray, R.H. and Kurtz, L.T. (1945). Determination of total,
organic and available form of phosphorus is soils. Soil
Science 59: 39-45.
Bremner, J.M. and Mulvaney, C.S. (1982).Nitrogen-Total. pp.
595-624. In: A.L., R.H. Miller and D.R. Keeney, (eds).
Methods of Soil Analysis, Part 2. Am. Soc. Agron.,
Madison, Wiscosin, USA.
Chapman, H.D., (1965). Cation Exchange Capacity.pp: 891-
901. In: Black, C.A. et al., (ed.), Methods of Soil Analysis,
Part 2 – Chemical and Microbiological Properties. Am.
Soc. Agron., Inc., Madison Wisconsin, USA.
Chroth, B., Vanlauwe and Lehmann, J. (2003). Soil Organic
Matter. pp. 78-79. In: G. Schroth and F. L. Sinclair, Eds.,
Trees, Crops and Soil Fertility, CAB International,
Wallingford.
Conant, R.T., J.six and K. Paustian, 2003. Land use effects
on soil carbon fractions in the South Eastern United
States: Management incentive versus extensive grazing.
Biology and Fertility of Soils 38: 386-392.
Dawit, S., Fritzsche, F., Tekalign, M., Lehmann, J., Zech, W.
(2002). Phosphorus forms and dynamics as influenced by
land use changes in the sub-humid Ethiopian highlands.
Geoderma 105: 21-48.
Day P.R. (1965). Particle fraction and particle size analysis.
pp. 545 -567. In: Black CA et al., (Eds). Methods of Soil
Analysis.Part 2.American Society of Agronomy, Madison,
WI, USA.
Eyayu, M., Heluf Gebrekidan., Tekalign Mamo and
Mohammed Assen. (2009). Effects of land-use change on
selected soil properties in the TeraGedam Catchment and
adjacent agroecosystems, north-west Ethiopia. Ethiopian
Journal of Natural Resources 11(1): 35-62.
Eylachew Zewdie (1999). Selected physical, chemical and
mineralogical characteristics of major soils occurring in
Chercher highlands, Eastern Ethiopia. Ethiopian Journal
of Natural Resource1(2): 173-185.
Getahun Bore and Bode Bedadi Sci. Technol. Arts Res. J., Oct-Dec 2015, 4(4): 40-48
48
FAO (Food and Agriculture Organization). (2006). Plant
nutrition for food security: A guide for integrated nutrient
management. FAO, Fertilizer and Plant Nutrition Bulletin
16, Rome.
He, Z.L., Alva, A.K., Calvert, D.V., Li, Y.C. and Banks, D.J.
(1999). Effects of N fertilization of grapefruit trees on soil
acidification and nutrient availability in a Riviera Fine
Sand. Plant Soil 206: 11-19.
Heluf Gebrekidan and Wakene Negessa (2006). Impact of
land use and management practice on chemical
properties of some soils of Bako area, Western Ethiopia.
Ethiopian Journal of Natural Resources 8(2): 177-197.
Hinrich L.B., Brian, L.M. and O’Connor George, A. (2001).
Soil Chemistry, John Wily & Sons, Inc., New York.
Jamison, V.C., Weaver, H.H. and Reed, I.F. (1950). A
hammer-driven soil core sampler. Soil Science 69: 487-
496.
Jaiyeoba, I.A. (2003). Changes in soil properties due to
continuous cultivation in Nigerian semiarid Savannah. Soil
Tillage and Research 70: 91-98.
Johnson, C.E. (2002). Cation exchange properties of acid
forest soils of the northeastern USA. European Journal of
Soil Science 53: 271-282.
Jones, J.B. (2003). Agronomic Handbook: Management of
Crops, Soils, and Their Fertility. CRC Press LLC, Boca
Raton, FL, USA. 482p.
Landon, J.R. (1991). Booker Tropical Soil Manual: A hand
book for soil survey and Agricultural Land Evaluation in
the Tropics and Subtropics. Longman Scientific and
Technical, Essex, New York. 474p.
Loma W oreda Agricultural Development Office (LWADO),
2013.AnnualReport for the year 2012-2013 G.C.
(unpublished report). Loma Woreda Agricultural
development Office. Loma, Ethiopia.
Mathewos Agize, Sebsebe Demissew and Zemede Asfaw,
(2013). Ethnobotany of Medicinal Plants in Loma and
Gena Bosa Woreda (Woredas) of Dawro Zone, Southern
Ethiopia.Topclass Journal of Herbal Medicine 2(9): 194-
212.
Matzher E., Pijpers, M., Holland, W. and Mandersheid, B.
(1998). Aluminum in Soil Solutions of Forest Soils:
Influence of Water Flow and Soil Aluminum Pools. Soil
Science Society of America 62 (2): 445-454.
Mulugeta Lemenih., Karltun, E. and Olsson, M. (2005).
Assessing soil chemical and physical property responses
to deforestation and subsequent cultivation in
smallholders farming system in Ethiopia. Agriculture,
Ecosystems and Environment 105: 373-386.
Murphy, H.F. (1968). A report on fertility status and other data
on some soils of Ethiopia.Collage of Agriculture HSIU.
Experimental Station Bulletin No. 44, Collage of
Agriculture: 551p.
Nanthi, S.B. and Mike, J.H. (2003). Role of Carbon, Nitrogen,
and Sulfur Cycles in Soil Acidification, In: Z. Rengel, Ed.,
Hand Book of Soil Acidity, University of Western Australia
Perth, Perth, 2003, pp. 42-43.
Nega Emiru and Heluf Gebrekidan, (2009). Influence of land
use changes and soil depth on cation exchange capacity
and contents of exchangeable bases in the soils of
Senbat Watershed, western Ethiopia. Ethiopian Journal of
Natural Resources11(2): 195-206.
Nega Em iru (2006). Land Use Changes and their Effects on
Soil Physical and Chemical Properties in Senbat Sub-
Watershed, Western Ethiopia. MSc Thesis, Alemaya
University, Alemaya. 89p.
Ogunkunle, A.O., and Eghaghara, O.O. (1992). Influences of
land use on soil properties in a forest region of south
Nigeria. Soil Use and Managements 8: 121-125.
Pam Hazelton and Brain Murphy (2007). Interpreting Soil
Test Results; What do all the numbers mean?. 2
nd
ed.
CSIRO Publishing, Australia.
Rowell, D.L (1994). Soil Science: Methods and Applications.
Longman, Singapore.
Saikh, H., Varadachari, C. and Ghosh, K. (1998a). Effects of
deforestation and cultivation on soil CEC and contents of
exchangeable bases: a case study in Simlipal national
park, India. Plant and Soil 204: 175-181.
Saikh, H., Varadachari, C. and Ghosh, K.(1998b). Changes in
carbon, N and P levels due to deforestation and
cultivation: A Case study in Simplipal National Park of
India. Plant Soil 198: 137-145.
SAS (Statistical Analysis System) Institute. (2004).
SAS/STAT user’s guide. Proprietary software version
9.00. SAS Institute, Inc., Cary, NC.
Schumann, W. and Glover, S. (1999). The Acid Soil Action
Pro-gram for Southern NSW, Proceedings 14
th
Annual
Conference, Queanbeyan, 13-15 July 1999, pp. 55-58.
Solomon, D., Fritzsche, F., Tekalign M., Lehmann, J. and
Zech, W. (2002). Soil organic matter dynamics in the sub-
humid Ethiopian highlands: Evidence from natural 13C
abundance and particle-size fractionation. Soil Science
Society of America Journal 66: 969-978.
Tefera Mengesha, Chernet Tadiwos, and Haro Workineh,
(1999). Explanation of the geological map of
Ethiopia.EIGS technical publication team, 2
nd
ed. Addis
Ababa, Ethiopia.
Tekalign Mamo, and Haque I. (1987).Phosphorus status of
some Ethiopian soils. I. Sorption characteristics. Plant
and Soil 102: 261-266.
Tekalign Tadese (1991). Soil, plant, water, fertilizer, animal
manure and compost analysis.Working Document No.
13.International Livestock Research Center for Africa,
Addis Ababa.
Teshome Yitbarek, Heluf Gebrekidan, Kibebew Kibret,
Sheleme Beyene (2013). Impacts of Land Use on
Selected Physicochemical Properties of Soils of Abobo
Area, Western Ethiopia. Agriculture, Forestry and
Fisheries 2(5): 177-183.
Turner II, B.L. (1995). Linking the natural and social
sciences.The land use/cover change core project of the
IGBP.IGBP Newslett 22. 6p.
Turner, B.L., Skole, D. and Sanderson, S. (1995). Land-use
and land-cover change: Science/Research plan. IGBP
Report 35 / HDP Report 7. IGBP Press Stockholm and
Geneva. 165p.
Walkley, A. and Black, C.A. (1934). An examination of
Degtjareff method for determining soil organic matter and
proposed modification of the proposed modification of the
chromic acid titration method. Soil Sciences 37: 29-38.
Woldeamlak Bewket and Stroosnijder L. (2003). Effects of
agro-ecological land use succession on soil properties in
the Chemoga watershed, Blue Nile basin, Ethiopia.
Geoderma 111: 85-98.
Yihenew Gebre Selassie and Getachew Ayanna,
(2013).Effects of Different Land Use Systems on Selected
Physico-Chemical Properties of Soils in Northwestern
Ethiopia. Journal of Agricultural Science, 5(4): 112-120.
... Such activities result in an increase in bulk density, a decrease in soil organic matter (SOM) content, and a decrease in CEC, all of which impair the fertility status of a particular soil type. Furthermore, changes in land use such as deforestation, continuous agriculture, overgrazing, and mineral fertilizer can produce major changes in soil characteristics and production reductions [17]. ...
... Similarly, Chimdi et al. [23] found that a decrease in total porosity in grazing and cultivated land soils compared to forest land soils was due to a drop in pore size distribution and the amount of SOM loss, which is dependent on the intensity of soil management techniques. Bore and Bedadi [17] also found that the quantity of SOM in grazing and cultivated areas has been reduced by 42.6 and 76.5 percent, respectively, when compared to forest soil. ...
... It is growing in both extent and scale, significantly reducing crop output. Soil acidity has a significant impact on the highlands of Dawuro, Gamugofa, Sidama, Kembata, Hadya, Siltie, Wolayita Guragie, Kafa, Ilu-ababor, Wallaga, Jima, West Shoa, North Shoa, Asosa, and Gojjam, for example [45,30,27,29,17]. ...
... Former studies point to that soil properties deteriorate due to the conversion of native forest and range land into cultivated land results in acidity of the soil (Lemenih et al., 2005) [18,10]. Such practices also result in decline in CEC and soil organic matter (SOM) content in order to reduce the fertility status of a certain soil type. ...
... One of the constraints to crop production on acid soil is low nutrient availability that are associated with soil acidity. If the soil pH is less than 5.5 Phosphate can freely be reduced unavailable to plant roots [18]. The amount of P in soil solution reqired for maximum growth of crops lies between 0.13 to 1.31 kg P per hectare as growing crops grasp about 0.44 kg P per hectare per day. ...
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... Intensive and continuous cultivation without proper land management has resulted in deterioration of soil physical, chemical and biological properties (Ragassa and Bekele, 2016). Getahun and Bobe (2015) reported that the amount of OM, TN and CEC in cultivated land have declined by about 76, 61 and 39%, respectively. Tesfahunegn (2016) found the highest soil organic matter, pH, total nitrogen, available phosphorus and clay under forest land as compared to cultivated land. ...
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Understanding soil physicochemical properties are necessary for the appropriate utilization of soil resources. Soil resource characterization and classification are major requirements. In view of this, a study was conducted on soils of the Jello-Chancho watershed in Liban District, East Shewa Zone of Ethiopia to characterize the physicochemical properties of the soil. To achieve these objectives, three profiles were opened from the watershed and examined for their selected morphological, physical and chemical properties. The morphological properties were examined in the field while physiochemical properties were analyzed in the laboratory and finally, the soils were classified. The soils were generally pinkish white to a black colour and had moderate to deep soil depth. The structure was granular in the surface horizons of all profiles while friable consistency in the moist basis of surface horizons in all profiles. Textural classes ranged from loam to clay whereas bulk density ranged from 0.90 to 1.18 cm-3 , and total porosity ranged from 55.47 to 66.00%. The soils were rated as moderate acid (5.6-6) to neutral (6.6-7.3). The electrical conductivity was low in all studied profiles. The organic matter contents in the study area ranged from 1.93 to 4.47% and total N contents ranged from 0.10 to 0.23%. The available phosphorus ranged from 0.02 to 3.86 mg kg-1. The exchangeable potassium, calcium and magnesium were high to very high in all studied profiles while sodium was very low to high. CEC of the study soils were ranged from 18.90 to 68.20 cmolckg-1 whereas per cent base saturation ranged from 53 to 98%. Depending on the results, the soils were classified as Abruptic Luvisols (profile 1), Haplic Luvisols (profile 2) and luvic Phaeazems (profile 3), respectively. The morphological and physicochemical properties of the soil for the study area change with topography and soil depth. Low levels of OM, available P, and total N could be the major problems in the study area. Therefore the results of this study concluded that increasing the extent of continuous and intensive cultivation with minimum conservation practices and erosion due to slope effect can further deteriorate soil properties. The control of such damaging effects would require proper soil conservation strategies.
... It seems that sustainable land management is the possible solution to the problem of natural resource degradation by preventing the degradation of soil and land and cause of stabilization and ensuring sustainable production for future generations (Gholami, 2010). Soil resource has also provided a great contribution in the production of food and fiber, in the maintenance of local, regional, and worldwide environmental quality (Bore and Bedadi, 2015). ...
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A study conducted in the Selaqui area of Dehradun, Uttarakhand, India was to assess and compare the changes in the physical and chemical properties of soils under different land-use viz. natural forest soil, agricultural (cultivated) soil, abandoned soil, and industrial soil. Soil samples collected randomly from the four sites with three replications for each land-use system, at two varied depth levels (0-15 cm and 15-30 cm). Results of this study indicated that the forest land recorded the highest moisture content, electrical conductivity, total nitrogen, organic carbon, available phosphorous and available potassium while the higher pH and calcium content were observed in an abandoned land and industrial land use respectively. However, the lowest moisture content, electrical conductivity, total nitrogen, and calcium content were recorded from abandoned land use; the pH from industrial land use and the available phosphorous and available potassium from agriculture (cultivated) land use.
... This might be because of higher values of OM content in shrubs and grassland than cultivated land. This is in line with Bore and Bedadi (2015) who stated the soil cation exchange capacity values in agricultural land uses reduced because of the reduction in organic matter content. ...
... Dawuro's southern, eastern, and northern strategic border positions were enclosed by vigorous defensive walls. The walls stretched from the borders of Gofa in its southwestern direction and extended to the borders of Wolaita, Kembata, Hadiya and Jimma zones in its northwestern direction [27,28]. About 57.71% of the people in Dawuro zone belongs to Protestants, 31.86% ...
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Background: Ethnoveterinary medicine is frequently used for treating various livestock diseases by many different ethnic groups in Ethiopia. To this end, the indigenous knowledge of medicinal plants and non-plant remedies has not been systematically documented and studied in the Dawuro zone. Therefore, a community based cross-sectional study design was conducted from November, 2017 to September, 2018 in order to identify and document medicinal plants and non-plant remedies used in animal health management. Methods: Relevant information on ethnoveterinary practice was collected from purposively selected 115 key informants using semi-structured questionnaire, focus group discussions, observations and field guided walk methods. The obtained data were analyzed using descriptive statistics, quantitative ethnobotanical methods and t-test and significantly test was set to p< 0.05. The plants claimed having medicinal value were collected and botanically identified. Results: The study revealed 103 plant species belong to 47 families and 11 non-plant remedies used to manage 36 different livestock ailments. Family Asteraceae accounted for 11.5% of the total species recorded. The majority of plants (56.2%) were harvested from wild habitat. Herbs (33.8%) were the main source of medicine followed by tree (30.6%). Leaves (43.6%) and roots (27.5%) were the main plant parts used while pounding was the major form in remedy preparation. The highest Informant Consensus Factor (0.83) value was scored for the disease of the reproductive system. Significant difference (P<0.05) was observed in average number of therapeutic plants reported by illiterate higher than literate groups. Cyphostemma flavicans (Baker) Desc. and Pentas schimperi were showed the highest Fidelity Level (100%) to treat disease of the reproductive system, and emaciation and bone fracture as plant materials whereas Bear faeces, sharp hot iron or wire/knife, and common salt were non-plant remedies used in the study area. Conclusion: The study revealed that the local community of in the study areas was used with a rich of indigenous knowledge of ethnoveterinary medicinal plants. The loss of valuable medicinal plant resources of the area calls for urgent and coordinated actions to develop conservation strategies.
... Thus, soil preservation greatly depends on determining the properties of the soils under present land-use types and understanding the implications that future changes in land use may have on overall soil health (Duguma et al., 2010;Tufa et al., 2019). Moreover, the concept of good soil health is central to ensure thriving agriculture with the ability to increase food production while preserving superior food quality and without negatively impacting environmental sustainability (Adnan et al., 2020;Bore and Bedadi, 2016;Liu et al., 2010). Rapid population growth is increasingly highlighting the need for more efficient use of resources and more sustainable use of agricultural lands Hunter et al., 2017). ...
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The effects of different land-use types on physicochemical properties and erodibility indices in suitable utilization of soil are the most important issue to be investigated. That’s why the current study was carried out to investigate changes in physical, chemical soil properties and erodibility indexes under different land-use types i.e., larch-fir forests, adjacent pasture, and riparian areas. Soil samples were collected from different land use in the Meydan Pond micro-basin. Five subsamples were taken at the 0-10 cm depth at five different sampling spots in each one of the three land-use systems (i.e., forest, pasture, and riparian areas). Results showed that silt content was around 38% higher in the forest soils over pasture and the riparian areas. Dispersion rate (80%) and erosion ratio (11%) were significantly higher in riparian areas over the pasture. In conclusion, pasture soils are resistant to erosion due to the higher amount of clay percentage (95%) and aggregation rate (38%) as compared to riparian areas that are more erodible. It is concluded that the river basin should be arranged according to the land capability classes’ principles to protect the soil's fertile layer from erosion to achieve the maximum productivity of crops.
... Thus, soil preservation greatly depends on determining the properties of the soils under present land-use types and understanding the implications that future changes in land use may have on overall soil health (Duguma et al., 2010;Tufa et al., 2019). Moreover, the concept of good soil health is central to ensure thriving agriculture with the ability to increase food production while preserving superior food quality and without negatively impacting environmental sustainability (Adnan et al., 2020;Bore and Bedadi, 2016;Liu et al., 2010). Rapid population growth is increasingly highlighting the need for more efficient use of resources and more sustainable use of agricultural lands Hunter et al., 2017). ...
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The effects of different land-use types on physicochemical properties and erodibility indices in suitable utilization of soil are the most important issue to be investigated. That's why the current study was carried out to investigate changes in physical, chemical soil properties and erodibility indexes under different land-use types i.e., larch-fir forests, adjacent pasture, and riparian areas. Soil samples were collected from different land use in the Meydan Pond micro-basin. Five subsamples were taken at the 0-10 cm depth at five different sampling spots in each one of the three land-use systems (i.e., forest, pasture, and riparian areas). Results showed that silt content was around 38% higher in the forest soils over pasture and the riparian areas. Dispersion rate (80%) and erosion ratio (11%) were significantly higher in riparian areas over the pasture. In conclusion, pasture soils are resistant to erosion due to the higher amount of clay percentage (95%) and aggregation rate (38%) as compared to riparian areas that are more erodible. It is concluded that the river basin should be arranged according to the land capability classes' principles to protect the soil's fertile layer from erosion to achieve the maximum productivity of crops.
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Background: Land-use change is one of the major factors affecting soil degradation. The pressures of the human population on land resources have increased land-use change with more negative effects on soil carbon storage and soil properties. The objective of this study was to assess the effect of land-use changes on soil organic carbon (SOC) stock and selected soil physicochemical properties in Gobu Sayyo, Western Ethiopia. Soil samples were collected from three adjacent land uses i.e., forest land, grazing land, and cultivated lands at 0-20cm and 20cm-40cm soil depths. A total of 36 composite soil samples were collected and the major soil properties and SOC storage of the area were analyzed and computed based on their standard procedures. Results: Soil organic carbon stock was significantly (p<0.05) higher (43.09-81.86 tone ha⁻¹) in forest land and was significantly lower (38.08-43.09 tone ha⁻¹) in cultivated land at the of depth of 0-20cm. SOC stock decreased with dept in all land uses. Changes in land use and soil depth affected the physical and chemical properties of soil. The physical soil property such as bulk density (BD) was higher (1.62 gcm⁻³) in the cultivated land whereas, the lowest (1.08 gcm⁻³) was recorded in the forest at 0-20cm depth. Comparatively the moisture content was higher (25.89%) under forest land at the depth of 20-40cm and was lower (11.22%) under cultivated lands. The chemical soil properties like exchangeable Ca2+, Mg2+, and K⁺ were higher in forest lands. Organic carbon, avP, TN, ex.Ca²⁺, ex.Mg²⁺, ex.K+, and CEC were lower under cultivated lands. pH increased with depth and was higher under forest land and lower under cultivated land. Soils of the study area are in general acidic to slightly acid with pH value ranging from 4-6-6.02. The pH, SOC, TN, av. Phosphorus and CEC were higher under forest land as compared to cultivated and grazing lands. Conclusion: It can be concluded that soil organic carbon stocks, the physical and chemical properties were affected by land-use change and depth. Therefore, reducing the intensity of cultivation, adopting integrated soil fertility management, and maintaining forest land must be practiced to save the soil of the area from degradation.
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Assessing land use-induced changes in soil properties are essential for addressing issues of agro-ecosystem transformation and sustainable land productivity. In view of this, a study was conducted to assess the impact of land use/land cover on the physicochemical properties of soils of Abobo area, western Ethiopia. Three adjacent land use types, namely forest, grazing and cultivated lands each falling under four land mapping units (1Ac, 1Bc, 2Cc and 3Cl) were considered for the study. A total of 40 random soil samples (0-20 cm depth) were collected to make three composite samples for each land use type across the land mapping units and analyzed for selected soil physical and chemical properties. The results of the study, on one hand, revealed that soil OM, total N, CEC, PBS and available micronutrients (Fe, Mn, Zn and Cu) contents of the cultivated land was significantly (P < 0.001) lower than the adjacent forest land. For instance, soil OM, total N, CEC, PBS, exchangeable Mg and available micronutrients (Mn, Zn and Cu) contents of cultivated land was significantly lower than the adjacent forest land by 32.98, 33.33, 16.16, 17.81, 21.88, 29.47, 40.05 and 53.92%, respectively. On the other hand, the results of the study revealed that exchangeable cations (Mg, K and Na), PBS and available micronutrients (Fe, Mn, Zn and Cu) contents of the gazing land was significantly (P < 0.001) lower than the adjacent forest land. However, significant differences were not observed between the forests and grazing lands in soil OM, total N, CEC and available P. From the present study, it could be concluded that the soil quality and health were maintained relatively under the forest, whereas the influence on most parameters were negative on the soils of the cultivated land, indicating the need for employing integrated soil fertility management in sustainable manner to optimize and maintain the favorable soil physicochemical properties.
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A study was conducted in the Tsegede highlands of Tigray Region, northern Ethiopia to determine the changes in some physical and chemical attributes across three adjacent acidic soil sites with different elevation and three land use types. Analytical results of the collected surface layer soil samples showed significant (P ≤ 0.05) correlation of soil bulk density, OM and total N with elevation. In the lower elevation site (Indaslasie), soil OM content declined by about 43 and 52% compared with that of the two higher elevation sites (Cheguarcudo and Indamariam), respectively. Soil pH, exchangeable acidity, exchangeable Al, OM, total N and available phosphorus also exhibited significant (P ≤ 0.05) disparity across the three land use types of the area. Soils of the forest land were less acidic by 0.43 and 0.68 pH units than the cultivated and grazing lands, respectively. The soil OM content of the cultivated land was significantly lower by about 25 and 35% than the grazing and forest land soils, respectively. Available soil P status was low and showed significant correlations with pH (r = 0.65), exchangeable acidity (r = –0.58) and Al (r = –0.53). In general, the study results revealed altitude did not impose any significant effect in aggravating soil acidity whereas land use type affected significantly not only soil acidity but also the important soil fertility related parameters such as OM, total N and available P contents. Therefore, it can be suggested that besides to the usual acid soil management and/or reclamation practices, introducing proper land use management systems are of paramount importance.
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We used natural C-13 abundance coupled with particle-size fractionation to evaluate soil organic carbon (SOC) dynamics following deforestation and subsequent cultivation in the subhumid Ethiopia highlands. Surface soil (0-10 cm), leaf, root, and litter samples were collected from natural forest and fields cultivated for 25 yr (Wush-wush) and from Podocarpus dominated natural forest and 30 yr cultivated fields (Munesa) and C, N and VC signature were measured. Total SOC declined by 55% (32.0 Mg ha(-1)) at Wushwush and by 63% (40.2 Mg ha(-1)) at Munesa following cultivation, while losses of N amounted to 52% (2.8 Mg ha(-1)) and 60% (3.1 Mg ha(-1)) at the two sites, respectively. delta(13)C values of bulk soils of natural forests at Wushwush (-24.3parts per thousand) and Munesa (-23.4parts per thousand) were significantly lower than those from the corresponding cultivated fields (-19.9parts per thousand, Wushwush and -15.5parts per thousand, Munesa). Deforestation and continuous cultivation at Wushwush and Munesa resulted in depletion of 80 and 96% of the initial forest-derived SOC in sand, while 73 and 85% of C-3 SOC was lost from silt fraction of the two sites, respectively. These results suggest that SOC in sand was a very labile component of SOM and is a more sensitive indicator to changes in soil C storage in response to land use changes. However, the substantial amount of forest-derived SOC lost from silt indicates that SOM associated with silt was also quite susceptible to management changes, and that at least in the soils under study represents a moderately labile SOM pool, which is generally not the case in temperate soils. Forest-derived SOC in clay declined by 48 and 61% at Wushwush and Munesa, respectively, suggesting that clay retained C-3 derived SOC more effectively and that SOM bound to clay was more stable than SOM associated with sand and silt fractions.