Effect of Biofilm Biofertilizer on the Performances of Native Plant Species in Degraded Grasslands at Knuckles Forest Reserve, Sri Lanka

Abstract

Lower montane forest in “Knuckles Forest Reserve” is important due to harbouring of high biodiversity and provision of watershed services to Sri Lanka. In the British colonial era, these forests were cleared for coffee and tea plantations. However, some of these lands were abandoned due to low yield. Presently, these abandoned lands are dominated with Cymbopogon nardus and they act as a barrier for reconnecting the fragmented forest patches. Therefore, this study aims (a) to restore lower montane forests on these grasslands by planting native plants in islands and with the application of biofilm biofertilizer (BFBF), (b) to indicate the potential use of BFBF in degraded grasslands for ecological restoration programs. Rhizosphere microorganisms were isolated from the seedlings of Macaranga indica, Bhesa ceylanica, Symplocos cochinchinensis and Eugenia bracteate. Among the isolates three different combinations of fungal and bacterial mixtures were selected as BFBF. A field study was conducted in four grassland blocks of three plot sizes (small 4 m2, medium 16 m2 and large 64 m2). Seedlings of above four species were planted randomly at 1 m interval in the plots. Half of each plot was treated with BFBF and the other half was kept as a control. Number of survived species and their heights were recorded every month. Significantly higher Relative Growth Rate (RGR) of the four species was recorded in the plots applied with BFBF. M. indica and S. cochinchinensis showed the highest RGR and the survival in all the plots. Eugenia bracteata observed the lowest survival.