Abstract:
Change in land use type is particularly from natural forests to cultivated lands, are the major
causes of physicochemical properties which lead low agricultural productivity. The aim of the
study was to evaluate the selected physicochemical properties of soil in different land use types
in selected sites of Gambela region, southwest Ethiopia, under four land use types (natural
forest, grazing, cultivated and fallow land) at two different depths (0 – 20 and 20 - 40 cm) in
three replicates and totally 24 composite soil samples were collected. The data were analyzed by
using appropriate methods. (Particle size distribution was determined by the hydrometer
method, soil pH was measured using a digital pH meter, Na and K was determined using flame
photometer and Ca, Mg and micronutrients were determined using Atomic absorption
spectroscopy. The data were analyzed by using SAS software. The results of particle size
distribution analysis in the study area revealed that the three land use types had clay texture but
cultivated land use type had clay loam texture. The mean pH (H2O) values observed in the
study area were within the ranges of slightly acidic (6.24 – 6.37), whereas, pH (KCl) values
ranged moderately acidic (5.25 – 5.48) the reason is because of high rainfall, conversion of
forest land to other land use types and intensive cultivation. The relatively highest mean value
of clay content, TP, pH-H2O, OC, TN, C: N, Av. P, PBS, exchangeable bases (K, Na, Ca and
Mg) and the micronutrients (Mn, Fe, Cu, and Zn) was recorded under forest land compared to
the other land use types due to the presence of high accumulation of organic matter and higher
biological activity in the forest land. It is possible to conclude that burning plant residues
practice during field preparation, removal of crop residues for animal feed and conversion of forest
lands to cultivated and grazing lands had negative effects on the soil physicochemical properties
of the study area. Therefore, it is recommended that soil pH is slightly acidic which
significantly affect land use types in the study area. Therefore, the concerned bodies or farmers
should focus to improve or maintain soil acidity particularly cultivated land by addition of
lime, reducing the activities that can affect physicochemical properties.
