WAKENE NEGASSA CHEWAKA1, HELUF HELUF GEBREKIDAN2
1Georg-August-Universität Göttingen, Institute of Agronomy in the Tropics and Subtropics, Germany
2Alemaya University, College of Agriculture, Department of Plant Sciences, Ethiopia
The success of soil management to maintain soil quality depends on an understanding of how soils respond to agricultural use and practices over times. Currently, large proportions of land in Ethiopia are rendered unproductive. The important soil quality indicators of Alfisols were investigated in 2001 in western Ethiopia under different land use systems to provide base line data for future research and development. The different land systems were the cultivated land, abandoned land, and the virgin land. One soil profile was opened in each system for field descriptions and laboratory studies. The soil physical properties such as structure, bulk density, total porosity and soil water characteristics showed notable variations due to different land use systems. The highest bulk density (1.57 Mg m-3) was recorded at abandoned land against (1.16 Mg m-3) in virgin land. Moreover, most of the soil chemical properties were affected. For instance, soil pH (H2O) was 5.23 in cultivated land as compared to 6.23 in virgin land. The lowest organic carbon and total nitrogen (1.24 and 0.08%) were observed in abandoned land whereas the highest (5.90 and 0.33%) was recorded in the virgin land, respectively. Similarly, the different forms of P were influenced due to different land use systems. The available P was found to be highest, 25.52 and 43.05 mg kg-1 in Olsen, and Bray-II extraction methods, respectively, in abandoned land as compared to 1.90 and 4.78 mg kg-1 in virgin land, because the abandoned land had received P fertiliser for the past three decades. The highest CEC (36.0 cmol(+)kg-1) was observed in virgin land whilst the lowest was (11.0 cmol(+)kg-1) in abandoned land. The essential micronutrients were also influenced due to different land use systems except for Mo which was trace in all land use systems. In general, continuous use of land for crop production without appropriate soil management has degraded most of the important soil physicochemical properties. Therefore, adoption of appropriate soil management and land use planning could replenish the degraded soil properties for sustainable agricultural productivity in the region.
Keywords: Abandoned land, alfisols, land use systems, soil properties, virgin land