PHYSICAL AND CHEMICAL SOIL PROPERTIES OF ORCHID GROWING AREAS IN EASTERN TURKEY

The aim of this study was to determine and characterize some physical and chemical soil properties of orchid growing areas in Eastern Turkey and to evaluate the differences in soil properties according to orchid species (Dactylorhiza spp., Orchis spp.). A total of 36 soil samples from different orchid growing areas were collected and analyzed based on water retention characteristics, pore size distribution, bulk density, electrical conductivity (EC), pH, organic matter, carbonates and micro elements. The results showed that physical and chemical parameters of soils did not vary regards to orchid species.   The amount of water retained at the low tensions (<0.03 MPa) in orchids growing areas soils were between 20.24 and 57.43 based on % of volume. The highest and lowest water retention capacity between 0.03-1.5 MPa was 30.96% and 5.15%, respectively. Among the samples, the highest and lowest volume of macropores and bulk density were between 36.85% and 13.79%, and 1.01 g cm-3 and 0.19 g cm-3, respectively. EC, pH, organic matter and CaCO3 values of samples varied from 0.47 dS m-1 to 2.97 dS m-1, from 5.71 to 7.81, from 1.06% to 38.96% and from 0.31% to 43.50%, respectively. In addition, the micro element (Cupper, Iron, Zinc, Cadmium, Lead, Chromium and Manganese) content of soils differed significantly from each other. It was noticed that higher altitudes of more than 2000 m were not suitable for the Orchis spp. whereas the Dactylorhiza spp.