Cell-wall degradation and nutrient release pattern in decomposing leaf litter of Bambusa tulda Roxb. and Dendrocalamus hamiltonii Nees. in a bamboo-based agroforestry system in north-east India
Decomposition dynamics, nutrient mineralization and cell-wall degradation of leaf litter of Bambusa tulda and Dendrocalamus hamiltonii were studied in bamboo-based traditional agroforestry systems of Arunachal Pradesh. Initial litter chemistry showed the identical leaf characteristics of both the species, but the species cannot be considered as good residue, as both of them had a greater initial C/N ratio (>25). The decay pattern showed three distinct phases during the field incubation period (0–90 days, 90–180 days and 180–270 days). The annual decay rate (k) varied from 3.34 in D. hamiltonii to 3.52 in B. tulda. N and P release from the decomposing litter was influenced by the seasonal cycle of mineralization and immobilization processes. Net mineralization was rapid during the later stage of decomposition. N and P remaining after 90% of decomposition in the decomposing leaf litter were 8.85–9.45% and 0.47–1.40%, respectively, in B. tulda and D. hamiltonii. The concentration of lignin increased, whereas cellulose and hemicellulose decreased during decomposition. Overall, the study revealed that Bambusa sp. have a higher N content and less lignin and carbon contents in their leaf litter and in addition they decomposed more rapidly than the residues of Dendrocalamus sp. Hence, B. tulda can be considered more suitable than D. hamiltonii for nutrient enrichment in traditional agroforestry and/or in the rehabilitation of the degraded jhum land.