Soil CNP Ecological Stoichiometry Characteristics Of Four Forest Types Of Mao'er Mountain

Maoershan National Nature Reserve is located in the northern part of Guilin,Guangxi Zhuang Autonomous Region.Maoer Mountain Nature Reserve is one of the most well-preserved areas in the world for its unique geograpHical location and high value of biodiversity conservation.It has been listed in 14 key areas of terrestrial biodiversity with international significance and 16 biodiversity fever areas in China.One of the spots is known as the "Green Treasury of Nanling Mountains in China".In order to provide theoretical support and scientific basis for the management of vegetation in the study area,the ecological indicators of four forest types in Maoershan Mountain were studied by means of stoichiometric characteristics.In this paper,the four forest types of pHyllostachys pubescens,Cunninghamia lanceolata,Schima superba and Cyclobalanopsis brownii in Maoershan Nature Reserve were taken as research objects,and soil C,N of the four forest The characteristics of P eco-chemometrics were studied and the following conclusions were drawn:(1)Soil C content of four forest types in the study area showed a downward trend with the deepening of soil depth,and tended to be stable.In addition to the effects of soil bulk density and soil pH value,the difference of soil C content may be related to different vegetation types.Soil N content of four forest types in the study area showed a downward trend with the deepening of soil depth,similar to soil C content.The soil P content is the highest in the surface soil,while soil P content distribution tended to be stable in soils below 15 cm.There were significant differences among C,N and P elements in four forest types.The results showed that except for soil bulk density,soil pH value,precipitation and temperature caused certain distribution of C,N and P contents in soil,different species had different absorption and utilization rates of C,N and P elements in soil.The difference of nutrient release rate of litter may be the main factor causing the difference of distribution of C,N and P elements.(2)Compared with deep soil,the mineralization rate of surface soil is lower in the study area due to the limitation of microbial activities to a certain extent.C/P showed a decreasing trend with the deepening of soil layer.Among the four forest types,the C/P ratio of each soil layer of Cyclobalanopsis brownii was significantly higher than that of the other three forest types,indicating that Cyclobalanopsis brownii was the most pHospHorus-fixing potential vegetation in the four forests.There was no significant difference in N/P ratio among different forest types and soil layers.The results showed that forest growth in the study area was not restricted by soil P.(3)Soil C,N and P contents and their stoichiometric correlation are mainly affected by forest classification,research scale and forest origin.Among them,C,N and P are mainly influenced by forest classification types.C/N,C/P,N/P and C,N,P show differences in different forest origins,while in different scales,soil C,N,P contents and their stoichiometric correlations show different rules under most conditions.(4)The relationship between soil factors and soil stoichiometric characteristics is not obvious in the ecosystem of a single forest type scale,but in a larger scale,the change of soil factors can have a significant impact on soil stoichiometric characteristics.On the one hand,the natural conditions of a single forest type are very similar,and the change range is small,so it is difficult to observe the changes.On the other hand,the experimental results also reflect the large-scale stability of soil factors and soil stoichiometric characteristics,and the universality of this relationship in terrestrial ecosystem biological sites.The study of geochemical cycle is of great significance.