Comparison of soil quality parameters under different land use and management systems in the highlands of Ethiopia

Abstract

In response to the prevailing low soil pH and associated problems in the highlands of Ethiopia, conversions of
natural vegetations and agricultural lands to other land use and management systems have been in practice since
several decades. A study was conducted to compare several soil physical, chemical and biological properties
under three land use (grassland, cropland, eucalyptus) and two management systems (limed land and fallow
land) all existing adjacent to each other. Results showed that soil quality indicators were higher under grassland
than under the other land uses and management systems considered. As compared to grassland a reduction of
53, 45, 46 and 47% in soil organic carbon (SOC) was observed under cropland, eucalyptus, limed and fallow
lands, respectively. However, cropland, eucalyptus and limed lands showed similar values for most of the soil
chemical properties studied. Soil microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) were
also significantly higher under grassland, and significantly lower under fallow land. Soil depth only affected
available phosphorus, Mg 2+ , exchangeable acidity, ratios of MBC to SOC, and MBN to total nitrogen (TN).
Therefore, our results suggest that SOC, MBC: SOC and MBN:TN could be considered to assess functional
capacities of soils under soil acidity conditions in the highlands of Ethiopia.