Effects of Agronomic, Orchard and Forest Land Uses on Soil Quality Index (SQI) in West Azerbaijan Province

Land use has considerable effect on soil properties and awareness of these properties is necessary to preserve ecosystem stability and increase the soil productivity. In this study, the effects of agronomic (alfalfa and wheat), orchard (apple) and forest (chestnut) land uses (over 30 years) on soil chemical properties in West Azerbaijan province were evaluated. About 75 soil samples were randomly collected from surface soil of each land use for the depth of 0-20 cm and some of their chemical properties as well as the soil quality index (SQI) of the soil of each land use were determined. Results showed that the soil organic carbon (2.8%) and total nitrogen (0.20%) in forest land use were significantly higher than those in the other land uses. Available phosphorous in the soil of the apple orchards (16.2 mg kg-1) was higher than those in the soils of the agronomic (12.6 mg kg-1) and forest (10.6 mg kg-1) land which can be attributed to the high phosphorous fertilizer application in the orchards. The amounts of pH, EC and CaCO3 in soil of the forest land use were less than those in soils of the other land uses. Assessment of soil quality index (SQI) showed that organic carbon, pH and available phosphorous as minimum data set (MDS) had the highest effect on quality of studied soils. Soil quality index in the forest land use (1.4) was significantly higher than those in the orchard (1.3) and agronomic (1.2) land uses. It is concluded that the land use effects on the soil qualitative propertise can be intensified with the organic matter input rates and tillage activities.