Leaf Litter Decomposition and Nutrient Release Patterns of Chirpine, Cupressus Plantation, and Oak Dominated Forest

Abstract

Litter decomposition study on Oak (Quercus griffithii), Cupressus (Cupressus sp.) and Chirpine (Pinus roxburghii) was carried out at Talo geog, Punakha Dzongkhag. The objectives of this study were to examine the rate of leaf litter decomposition (mass loss) and nutrient release pattern under three forest types using the litter bag technique. Two replicate plots (20 x 20 m) were established in each forest type and in each replicate 24 litter bags were laid on the forest floor. Samples were drawn at the interval of 4, 8, 12, 16, 20, 24, 28, 32 weeks and analysed to determine the mass of dry matter remaining and, carbon and nitrogen contents. Highly significant differences (p < .01) were observed in mass loss and nutrient released among different leaf litters. Oak litters lost the maximum mass and nutrients compared to the other two litters. Carbon to Nitrogen (C:N) ratio and nitrogen immobilisation of the three litter types were in the order of Chirpine > Cupressus > Oak. Oak litters with high initial nitrogen content and low C:N ratio decomposed faster than Cupressus and Chirpine needles. The immobilisation nature and high C:N ratio of Chirpine and Cupressus litters indicate their poor litter quality. On the contrary, the fast decomposing Oak litters with high N and low C:N ratio readily releases the nutrients to enrich soil fertility. Study of nutrient dynamics of litters in different forests is important for a greater understanding of the nutrient cycling in the forest ecosystems in the country.