Foliage decomposition and nutrient release dynamics of Bambusa balcooa and Bambusa pallida in a 9-year-old jhum fallow

Abstract

Litter decay and nutrient release rates of leaf and leaf sheath litters of Bambusa balcooa Roxb. and B. pallida Munro were determined using the litter-bag technique in a 9-year-old jhum fallow in the humid tropics of north east India. C concentration was highest in leaf and leaf sheath litters of B. pallida, while N and lignin concentrations were greater in B. balcooa litter. Both leaf and scale leaf litters of B. balcooa and B. pallida showed similar decomposition patterns. The daily decay constants did not differ significantly between the two litter types and among bamboo species studied. Nonetheless, mass-loss rates during decomposition of the leaf and leaf sheath litters of both the species showed positive correlations with incubation period (the time after burying the samples in the soil). In general, until 120 days of incubation, there was N immobilization and later during the study period rapid release occurred. The release of N from B. pallida is greater than B. balcooa as per KN values. P was initially being immobilized followed by a gradual release after 120 days of litter decomposition in B. balcooa. In B. pallida, no definite pattern was observed. The rate of weight loss and N release showed significant positive relationships with lignin and N concentrations and lignin/N, C/P and N/P ratios, and negative relationships with C and P concentrations and C/N ratio. However, release rates of P did not show significant correlations with most chemical compositions of the litter except with initial P concentration, C/P ratio and lignin/N.