Effect of Micro-Topography and Edaphic Factors on the Asafoetida Volatile Oil Components

Asafoetida volatile oil components (AVOCs) are directly affected by microenvironmental changes. Here, this research aimed to investigate the AVOCs through gradients of micro-topography and edaphic factors in an arid area in central Iran (northern hemisphere) during two consecutive years. Soil and topography data were sampled simultaneously with oleo-gum-resin sampling using 20 plots placed in the area. Data were submitted to a PCA analysis. The AVOCs were significantly affected by both micro-topography and soil properties (P < 0.01). The components of carbonothioic dihydrazide and 1,3,6-0ctatriene, 3,7-dimethyl showed the most negative and positive relationship with the micro-elevation from 0 to 60 cm (R2 = 0.39, 0.44, respectively). Some components showed severe changes depending on the geographical direction, where the highest (42.2%) and lowest (25.1%) values of carbonothioic dihydrazide were obtained under the geographical direction of south and north, respectively. Also, nitrogen, phosphorus, organic matter and silt with R2 = 0.72, 0.52, 0.84 and 0.63, respectively, were positively correlated with some AVOCs, i.e., thiopropionamide and naphthalene, 1,2,3,5,6,8a-hexahy….