Soil and rainfall factors influencing Artemisia sieberi species growing in the steppe rangelands, Yazd province

Range management concerns the important knowledge on indicator plant species, in particular, their ecological behavior in relation to the main environmental variable. This study aimed to assess the effect of important environmental variables such as rainfall and soil characteristics on Artemisia sieberi species in the steppe region of Yazd. For this purpose, 14 various habitats of this plant species were selected and their canopy cover and forage yields were measured using plot-transect method in each year. For each sampled habitat, one composite sample was collected from profiles of 0-40 cm depth. Measured soil properties were included: gravel, texture, organic matter, calcium carbonate (TNV), gypsum, pH, EC, soluble ions (Na+, Mg2+ and Ca2+) and SAR. Rainfall data was collected from nearby climatological stations. The relationships between A. sieberi and environmental variables were determined using of Redundancy Analysis (RDA) method. Application of RDA indicated that on the first canonical axis, mean annual rainfall, organic carbon, percentage sand content and EC have the highest intra-set correlation (r = 0.8, r = 0.63, r = -0.74 and r = -0.38), thus were as the strongest effective environmental variables for Artemisia sieberi growing parameters. Calcium carbonate (TNV) and saturation percentage (SP) showed significant correlation with CCA axis 2 (r = 0.65 and r = -0.43) and had lower effect on this species. These mentioned environmental gradients accounted for 83% of the species–environment relationship among the study sites.