Study of soil-vegetation interrelationships in galbanum (Ferula gummosa) habitats (Case study: Rangeland of Ataeeye and Shoorrud- Khorasan-e- Razavi Province)

Determination of vegetation and soil interaction is necessary for sustainable use of rangeland ecosystem. Soil-vegetation interrelationships in galbanum (Ferula gummosa) habitats of Ataeeye and Shoorrud- Khorasan-e- Razavi Province, Iran were studied using multivariate analysis. The stratified- random system of sampling was employed to randomly collect vegetation and soil samples from 46 quadrats of 3 m× 3 m. Data was analyzed by Principle component analysis (PCA), recognize variables with highest effect on total variance in soil and vegetation characters and Canonical correlation analysis (CCA) for determining of interrelationships between soil and vegetation variables. Result of PCA indicated that organic matter, soil texture, nitrogen content, water content in saturation point and soil cations content were the major soil properties contributed in total variance, and plant density, diversity, vegetation biomass and secondary metabolites concentration were the main vegetation parameters. Result of the first canonical variable indicated that 65 percent of the variance in vegetation characteristics was accounted for by the variability in soil. The correlation analysis indicated that organic matters and soil water content positively influenced vegetation biomass and diversity, while had negative association with phenolic content of galbanum. Soil Calcium content had negative correlation with biodiversity and vegetation biomass. It was concluded that soil and vegetation components of the galbanum habitats in study area were mutually dependent and Calcium and organic matter content were the most important and effective variables on galbanum establishment.