Role of allelopathy in regulating the understorey vegetation of Casuarina equisetifolia

A study conducted under the 14 year old plantations of Casuarina equisetifo lia reveals the reduction of understorey vegetation in comparison to the ad joining open areas. The number of plants, species type and the biomass were greatly reduced under the plantations. The leachates from fresh leaves and litter and the understorey soil were found to be rich in phenolics and exh ibited phytotoxic effects against the Bidens pinnata and Parthenium hystero phorus which were obscured from the plantations but were present in the adj oining area. Both the germination as well seedling growth of these two plan ts was significantly reduced in response to the different leachates. Thus, allelopathy was observed to play a significant role in regulating the under storey vegetation dynamics in C. equisetifolia stands.