Carbon and Nitrogen Return by Litter of an Eucalyptus urophylla×E. grandis Plantation in Sandy Coastal Plain Area

A oneyearlong field study was conducted to measure litterfall quantity and its carbon and nitrogen return of an 10yearold Eucalyptus urophylla × E. grandis plantation on a sandy coastal plain soil in southeast Fujian Province, China. The annual litter production of the studied plantation was 6739.92kg/(hm2·a), of which leaf litter was the main component. The quantity of the litterfall dynamically changed along the seasons, expressing “double peaks” individually in May and July of the year. The carbon content of litter components varied from 45% to 50% and there was no distinct difference in carbon content among the components. Whereas the nitrogen content in the leaf litter was 2-3 times higher than that of in bark and twig litter,which was in the order as miscellaneous>leaves > fruits >twigs > bark. The total annual return of carbon and nitrogen from litterfall was 3325.86 kg/(hm2·a), of which 3267.48 kg/(hm2·a) was carbon return and 53.89 kg/(hm2·a) was nitrogen return. C/N ratio of the litterfall was 55.96, which was higher than that of other tree species in this trial site, and the ratio among the components followed the order as bark > twigs > fruits > leaves > miscellaneous.