Comparison of Soil Physical and Chemical Properties in Grassland and Shrub Land Communities, Iran

Abstract

Proper management of rangelands is based on ecological principles, and an understanding of ecological processes is a precondition of the right management. Composition and construction of each plant community are largely under the control and influence of edaphic factors, and these factors help to identify growing plants of their own region. Determination of the scientific relationship between soil factors and vegetation in each region and its expansion to other similar regions will be important achievements in the management of rangelands. The aim of the study was to compare the physical and chemical properties of soil in the two communities of shrub land and grassland. For this purpose, two sites of grassland and shrub land were selected in the rangeland of Vavsar Kiasar. Vavsar is located in longitude 45′′ 43′ 53°–35′′ 37′ 53° and in latitude 13′′ 10′ 36°–40′′ 5′ 36°. Climate was semi-arid to semi-humid and Mediterranean, using the Domartin method. Dominant plant species in the shrub land were Artemisia aucheri, Astragalus caspicus, Acantholimon bodeamun, and Stachys infelata, and species Festuca ovina, Stachys inflata, Noea mucronata, and Ephorbia cheiradenia were dominant in grassland. Sixty soil samples from each site were taken from two depths, 0–15 and 15–30 cm. In the laboratory, soil properties including organic carbon (OC), total nitrogen (TN), electrical conductivity (EC), calcium carbonate (CaCO3) percentage, moisture content, and percentages of clay, silt, and sand were measured. The comparison of mean soil properties was performed between the two communities and two depths by using the T-test. The results showed that there was a significant difference in the level of 5% among electrical conductivity, moisture content, and clay percentages at two depths of soil in the shrub-land site but there were no significant differences in soil factors between the two depths in the grassland site. There was a significant difference in the first depth of soil between shrub-land and grassland communities according to percentages of sand and silt, electrical conductivity, and CaCO3 and organic-matter percentages and in the second depth between the two communities for electrical conductivity, CaCO3 percentage, and clay percentage. In conclusion, soil condition in the shrub land was more desirable than in grassland because there was a greater percentage of vegetation and grazing intensity was less.