Temporal and Vertical Variation of Selected Extracellular Enzyme Activities on Tree Litter Degradation of a Subtropical Forest

Abstract

The present study focused on the soil enzyme activities through in situ incubation of litter decomposition pits across major seasons in a subtropical forest of Bengal. This study examined the activities of extracellular enzymes (amylase, cellulase and invertase) and their relationship with the types of litter decay and soil physiochemical properties at different depths of the soil matrix. The higher decay constant (k) of decomposed leaf litter was recorded for Tectona and lower for Albizia in the studied three seasons. The results also revealed that the activities of soil extracellular enzymes were higher in rainy season compared to winter in all experimental sites with respect to control. Among the studied enzymes, invertase was significantly higher in different decomposed sites at the surface soils compared to other enzymes during the rainy season. The results also demonstrated that the enzyme activities gradually declined from the surface soil to subsurface soil at the different decomposed sites. However, in surface soil, the amylase and invertase activities were highest in Tectona litter-containing soil and cellulase activity was highest in Shorea litter-containing soil in all the studied seasons. On the other hand, soil parameters such as moisture, organic carbon and available nitrogen were significantly correlated with enzyme activities in different decomposed sites. The results suggest that the activity of the extracellular enzymes involved in litter decomposition varies in different species and seasons.