Accumulation and distribution characteristics of nutrients in Pinus yunnanensis forests with different ages
[Objective] The content,accumulation,distribution and their changing trends along with forest stand age of five nutrient elements (N,P,K,Ca,and Mg) in natural secondary Pinus yunnanensis forest in Mopan mountain,Yuxi City,Yunnan Province were studied,to improve nutrient utilization and estimation of forest ecological value.[Method] Natural secondary Pinus yunnanensis forests with ages of 15,30 and 45 years were selected,and three 20 m × 20 m standard samples were set in each forest.Samples were collected from leaves,branches,stems,and roots of arbor layer plants,leaves,twigs,and roots of shrubs,aboveground and underground parts of herbs,and all parts of litter in each sample plot.Biomass and nutrient elements of mixed samples from same organs of same plants were analyzed in laboratory.[Result] The contents of nutrition element in Pinus yunnanensis were in a decreasing order of leaves＞branches＞roots＞trunk.N was the nutrient element with highest content,followed by K and Ca,Mg and P had the lowest contents.The accumulations of total nutrient elements of 15,30 and 45-year-old natural secondary Pinus yunnanensis forests were 192.00,930.95 and 2 357.36 kg/hm2,respectively.Arbor layer accounted for 70.70％,66.84％,and 98.82％,understory vegetation layer accounted for 22.97％,7.53％,and 0.43％,and litter layer accounted for 7.0％,26.98％ and 0.80％,respectively.N had the largest accumulation among all layers,while P was the lowest.The ratio of nitrogen content to phosphorus content decreased as the increase of forest age.The total of the five nutrient elements needed for accumulation of 1 t dry matter for Pinus yunnanensis with age of 15,30,and 45 years were 8.38,8.52 and 7.68 kg,respectively.The use efficiency of N was the least while that of P was the highest.[Conclusion] Pinus yunnanensis had high nutrient use efficiency,and it would not result in decrease of soil fertility due to excessive consumption of nutrient elements in the soil.Pinus yunnanensis has high resistance and good adaptability,and is suitable for afforestation in barren hills.
Pinus yunnanensisnatural secondary forestnutrient elementsaccumulation and distribution
NETL
NSTL
万方数据
维普
