Litterfall, litter decomposition and nutrient release in five exotic plantspecies planted on coal mine spoils

Litterfall, leaf litter decomposition and nutrient dynamics (N, P, K and Ca ) were studied for four years in old plantations of five exotic plant speci es namely Acacia auriculiformis, Cassia siamea, Casuarina equisetifolia, Eu calyptus hybrid and Gravelia pteridifolia growing on coal mine spoil. Maxim um litterfall on mine spoil was found during cooler and drier seasons than in to the hotter and moist. Total litterfall was maximum for G. pteridifoli a and minimum for C. siamea. Litter of different plant species showed varia tions in their decomposition. The mean relative decomposition rate was maxi mum in the rainy season and minimum during summer, The concentrations of N and P increased, whereas K and Ca decreased in decomposing litter with incr easing retrieval days. Mass loss was negatively correlated with N and P con centrations, whereas the same was positively correlated with K and Ca. Maxi mum litter decomposition rate was recorded for C. siamea, whereas G. pterid ifolia showed the slowest decomposition rate. The plant species A. auriculi formis, E. hybrid and C. equisetifolia were found to be most suitable for p lanting on mine spoils as these have led to the most balanced nutrient cycl ing with both moderate litter deposition and decomposition rates.