effects of hedysarum criniferum boiss. as a plant symbiotic with nitrogen fixers on some chemical properties of the soil

plants have noticeable effects on soil resources distribution and its biochemical processes, and organic materials are naturally much more in the understory soil as compared to open areas. vegetation as one of the soil formation factors is not always an independent variable, so that the soil and vegetation can have interaction. the present study was conducted to investigate the effects of hedysarum criniferum on some chemical properties of the soil. for this purpose, sampling of soil under the canopy of hedysarum criniferum and bromus tomentellus (non-legume plants as control) as well as the control soil (no plant) at 0-30 and 30-60 cm depths was conducted in a completely randomized design. the chemical properties of the soils, including caco3, ec, ph, organic carbon, inorganic nitrogen and total nitrogen percent in soil were measured. furthermore, the criterion plant analysis was studied at laboratory scale to test the effect of the plants on the amount of total nitrogen, protein and plant production. results showed that the amounts of inorganic nitrogen, total nitrogen content and organic carbon as well as the criterion plant’s total nitrogen content and plant production at 0-30 cm soil depth were significantly different from the control soil and bromus tomentellus (p<0/05) and were decreased with increasing depth.