Research On Ecological Stoichiometry Characteristics Of Carbon,nitrogen And Phosphorus In Larix Principis-rupprechtii Plantation Of Qinling Mountains

Carbon(C), nitrogen(N) and phosphorus(P) play an important role in forests growth. The contents and ratios of C, N and P element reflect the nutritional status and healthy growth of forests. Ecological stoichiometry is an emerging ecological research field in recent years.The relationship between nutrient elements in the ecosystem can be better revealed through discussions on the characteristics of C, N and P ecological stoichiometry. In this study, we collected the 7 year old(7 a), 12 year old(12 a), 22 year old(22 a), 32 year old(32 a) and42 year old(42 a) Larix principis-rupprechtii plantation in Qinling to explore the content of C, N and P and their ecological stoichiometry characteristics of fine roots, stems and needles in different seasons, to provide a theoretical basis for fertilization management, but also provide a theoretical basis and technical support for NP absorption, utilization and return mechanism of the forest on soil nutrient balance.The main results were as follows:(1) The study found that the ratio of N: P in five different ages of needles in Larix principis-rupprechtii was less than 14, respectively. N is a restrictive factor for young and middle-aged, near mature and mature Larix principis-rupprechtii plantation of Qinling Mountains. N fertilizer should timely be supplement in this place to meet the nutritional needs of the normal growth of Larix principis-rupprechtii.(2) Nitrogen content in fine root of Larix principis-rupprechtii increased with increasing stand age. The content of nitrogen was significantly higher in near mature and mature Larix principis-rupprechtii than that in young and middle-aged. This showed that N content in fine root was relative to the number of growing years.(3) Correlation analysis indicated that C: N mass ratio and C: P mass ratio were negatively correlated with corresponding N, P content of needles, fine roots and stems in differentages of Larix principis-rupprechtii(P <0.05). N: P mass ratio of leaf was correlated with corresponding N(P <0.05), and N: P mass ratio of stem was correlated with corresponding P(P <0.05).(4) Larix principis-rupprechtii is a kind of perennial deciduous trees. The characteristics of C, N and P ecological stoichiometry were relatively stable in fine roots. It can be used to participate in the analysis of ecological system problem because its quantitative characteristics in fine roots were affected less in different seasons in Larix principis-rupprechtii in Qinling.