Evaluation of physicochemical properties of soil, in different land use types in selected sites of gambela region, southwest Ethiopia.

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.