the study of some habitat characteristics of hulthemia persica in gonbad watershed in hamedan (iran)

in this study, some habitat characteristics of iranian rose (hulthemia persica) were studied in gonbad watershed in hamedan providence, iran. soil samples were taken by a systematic randomized method at elevation 2000-2400 m above sea level. samples were taken from 0-30 cm depth. in the laboratory, n, p, k% and organic matter (oc%), soil acidity (ph), conductivity (ec) and soil texture were determined. the collected data were analyzed and principal components analysis was performed on 14 variables using pc-ord software. results showed that these species are scattered in the height of 2100-2300 m above sea level with 15-65% slope in north, northwest, southeast and southwest as spot bulks. mean precipitation of this area is 227.5 mm. it’s vegetative, flowering and seed maturity stages occur in middle march, may and june, respectively. plant roots permeate into the depth of 1.5 m and plant propagated by both seeds and rhizome. however, its seed has hard coat resulting in a difficulty in germinating so that the seed propagation is not sexual and it propagated normally by rhizomes. this species growth in the soil with ec=0.08-0.36, ph=7.30-7.98, limestone soil 0.50-19.5%, oc=1.09-0.27%, saturation (sp%)=18.3-38.2%, n=0.02-0.10 %, p=4.8-40.6 ppm, k=155-652 ppm, and the soil texture was clay to clay-loamy. results of pca analysis indicated that the first three axes explained total variation. the variables of sp, ec and slope were positively and silt and aspect were negatively correlated with the first axis. the variables of sp, ph and oc% were positively and sand and n% were negatively correlated with the second axis. indicating that by increasing sand properties the ph values will decrease. there was also a negative correlation between vegetation coverage and slope (p