Assessment of soil quality indicators on different slope aspects in Duhok’s highlands (Kurdistan region – Iraq).

Abstract

This study was conducted to assess the influence of slope aspect on some physical, chemical
 and biological indicators of soil quality in Mountain in Brifka village that located at about
 20 km east of Duhok province in Iraqi Kurdistan region, having the same climatic, and
 vegetation. Soil samples were collected randomly and at uniform intervals along north and
 south facing slopes aspect. The soil quality has been represented by some physical,
 chemical and biological indicators such as: soil texture, bulk density, moisture content,
 organic carbon, pH, electrical conductivity, soil basal respiration, microbial biomass C,
 potentially mineralizable N and metabolic quotient. The results indicated that, except in few
 cases, the majority of studied soil quality indicators were significantly affected by slope
 aspect. The mount of soil moisture content, silt mineral fraction, soil organic C, soil basal
 respiration, microbial biomass was significantly higher in north facing slope compared to
 south facing slope, while sand fraction and bulk density were significant higher on south
 aspect than north aspect. No significant differences were found in clay fraction, soil pH,
 electrical conductivity, potentially mineralizable N and metabolic content. It was suggested
 that the slope aspect has effects on soil quality indicators and for better rangeland and
 landscape management it is very important to take the topographic aspect into
 consideration.