The Distribution pattern of carbon,nitrogen and phosphorus and the stoichiometry characteristics of Pinus massoniana plantation in different ages

In order to understand the distribution pattern of carbon、nitrogen and phosphorus and the stoichiometry characteristics of pinus massoniana plantation ecosystem at hilly area in upper reaches of the Yangtze River, we used the space-temporal exchanging method, and selected three different forest stand age(5-year-old young growth, 14-year-old half-mature forest, 39-year-old mature forest) of masson pine plantation in similar site conditions as the objects, and analyzed the concentration of carbon, nitrogen and phosphorus and w(C):w(N):w(P) stoichiometry characteristics in the needle leaf, litter and soil. The results showed that the concentration of C, N and P were significant difference between needle leaf, litter and soil which in order of needle leaf litter soil; forest age had significant impact on C, N, P concentrations and w(C):w(N), w(C):w(P) stoichiometry ratios; The C, N, P content of soil were the highest in the mature forest, while the C content of needle leaf and litter were lowest in mature forest, and the N, P content of needle leaf and litter was highest in the mid-maturation forest; N and P use efficiency of masson pine plantation reduced, as w(C):w(N) and w(C):w(P) ratio of needle leaf, litter and soil declined with forest age increasing; The w(N):w(P) ratio of needle leaf was between 14.37 and 15.53, which indicated that the masson pine plantation was restricted by N and P together, but the influence of N and P limitation was not significantly by forest age. To increase the productivity of pinus massoniana plantation in the area, we should appropriately increase N and P fertilization in the plantation tending management. In addition, we also could interplant the leguminous nitrogen-fixing plants to improve soil fertility. This study combined masson pine needles, litter and soil to explore the distribution pattern of C, N and P nutrient elements and the change of chemical measurement characteristics with forest age increasing, will help to reveal the nutrient cycling of pinus massoniana plantation ecosystem roundly and systematically, it is very significant to guide the production of pinus massoniana plantation, adjust and improve the growth environment of masson pine, improve the nutrient use efficiency and the forest land productivity of the system.