Abstract: By using chronosequence method, an investigation was conducted on the annual litter mass and nutrient return of Masson pine plantations at different ages. The litter mass of the plantations varied obviously with season, and affected by species characteristics and climate. There was a lag effect of climate on litter mass. The nutrient concentrations in each litter component had an obvious seasonal variation, with the difference reached more than one-fold. With increasing stand age, the K return through litterfall decreased, while the other nutrients return showed ‘V’ shape. The stand at age 51 had higher nutrient use efficiency. Litterfall played an important role in maintaining stand fertility. Litter output, especially for fallen needles, would cut the key link of biogeochemical cycle, aggravate the nutrient deficiency of soil, and lead to the decrease of stand productivity. Therefore, in the management of Masson pine plantation, litter output should be reduced as possible to maintain the long-term productivity of the site.

Key words: Genetically Engineered Microorganism, Ecology, Environment