Assessment of seedling emergence method in soil seed bank in two states of washing and non-washing

This study aimed to evaluate the results of soil seed bank in Tarbiat Modares Lowland Experimental Forest by using the two methods of washing and non-washing. Therefore, four main plots (40×40 m2)with each of them comprising 4 sub quadrats of 400 m2 were considered as representative stands. Aboveground vegetation was sampled by 16 plots of 400 m2 in two time steps of March and June. Seed bank flora was studied using seedling emergence method based on 64 soil samples (2 methods×4 main plots×4 replications×2 depths of 0-5 and 5-10 cm) which had been hammered by a hollow 400 cm2 metal frame. Statistical analysis was performed using split plot in space set within a randomized complete block experimental design. Results showed that both species richness and density of soil seed bank in non-washing method (63 species with 1872 seed density per m2 in upper layerand 46 species with 975 seed density in lower layer) were significantly higher than in washing method (45 species with 1137 seed density per m2 in upper layerand 33 species with 699 seed density in lower layer). Results also showed that similarity between soil seed bank with corresponding extant vegetation decreased with increasing soil depth. However, the two methods were not significantly different. We concluded that seedling emergence method without washing results in better soil seed bank assessment.