Abstract:
Changes of forests to other land uses are one of the most concerns in environmental
degradation and world climate change. The study was conducted in Tejibara watershed to
assess the effect of different land use types and soil depths on selected soil physicochemical
properties. A total of 24 composite soil samples were collected from the identified (cultivated,
forest, grazing and eucalypts plantation) land use types and two soil depths (0-20 and 20-40
cm). Selected soil physical and chemical properties such as texture, BD, moisture, pH, EC,
OM, TN, AP, CEC and ex. K were determined following the standard laboratory procedures.
For data analysis, General Linear Model (GLM) procedure of Statistical Analysis System
(SAS) version 9.4 was used. The study results showed that, sand fraction, CEC and K were
not significantly affected by land uses soil depths and interaction effect. Whereas, silt, clay
fraction, AP, pH and SMC were significantly affected by land uses, but not affected by soil
depths and their interactions. BD of the soil in the study area was highly significantly affected
by land use and soil depths. TN, EC and OM content was highly significantly affected by land
uses, soil depths and interaction effects. The relatively higher (10.14 mg/kg) and lower (4.93
mg/kg) AP contents were observed under the forest and the grazing lands, respectively.
Similarly, relatively higher and lower BD values were recorded at cultivated (1.52 g/cm
3
) and
forest (1.02 g/cm
3
) lands. On the other hand, relatively TN higher in surface of forest land
(0.35%) and lower N content of the soils was recorded in surface cultivated lands (0.05%),
respectively. The soil pH values ranged from 5.99 in the plantation forest to 6.53 in forest
lands. The soil OM content relatively lower value of 0.65% observed in subsurface of
cultivated lands to 12.9% observed in surface of forest lands. Generally the results of this
study showed that, OM. TN and EC soil parameters were significantly affected interaction
effects, most of the selected soil parameters were significantly affected by land uses and soil
depth. This result implies that land use change especially from forest to other land use types
generally aggravate the observed problems in soil fertility indicating the risk of sustainable
crop production in the area. For future research direction, soil physicochemical assessment
should be done frequently since soil is a dynamic and complex system
