An Assessment of the Rangeland Soils on the Saiq Plateau, Jebel Akhdar, Oman

Abstract

Variables indicating the stability and hydrologic functions of rangeland soils of the Saiq Plateau have never been assesed.  We used standard soil analytical methods to quantify soil texture, stability, organic matter and water holding capacity at 14 sites across the width of the Plateu.  The soils were mainly loams.  Three-fourths of the 756 transect samples were unstable, indicating the landscape is vulnerable to erosion.  Although the quantity of organic matter (1.7-7.6%) is similar to North American grasslands, the soils were often azonal and lacked a dark humic layer, suggesting low rates of decomposition.  Soil organic matter and water-holding capacity are significantly correlated (P<0.0001) and both variables are significantly greater under trees and shrubs than on open rangeland (P<0.0001).  This pattern of higher concentrations of organic matter around perennial vegetation and notably less in the plant interespaces characterizes heavily grazed rangelands.  A livestock management plan is suggested that could allow soils and vegetation to recover.