Abstract
Changes as brought about in diversity of floral species and in chemical properties of soil under pure plantations of Robinia pseud-acacia and mixed plantation raised over the mine overburden areas of Paonta Sahib in Sirmour District of Himachal Pradesh were studied during August, 2000. The number of ground flora species under Robinia pseud-acacia and mixed plantation was 25 m-2 and 31 m-2 respectively. On the basis of importance value index (IVI), Peristrophe bicalyculata and Ageratum conyzoides were the dominant herbs under Robinia pseud-acacia and mixed plantation respectively. Distribution pattern reflected that most of ground flora species were contiguous. Index of dominance was found to be lower and diversity index was recorded higher for ground flora under plantations while compared with exposed mine overburden area. The ground flora under mixed plantation however, showed the highest diversity index (4.168). Index of dissimilarity between plantations and exposed mine overburden area was high thereby indicating remarkable degree of dissimilarity in ground flora species. Plenty of similarity between two plantations was however observed as far as ground flora growing under them was concerned. The chemical properties of soils as assessed under plantations showed improvement in fertility status while compared to exposed mine overburden areas.
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