Study On Soil Ecological Stoichiometry Characteristics In Sejila Mountain Forest Area

In the interconnected plant-soil system,soil has certain fertility and can provide water and mineral nutrients for plant growth and development.Soil structure,water and mineral nutrient content not only determine the individual development of plants,but also affect plant type,distribution and dynamics.On the contrary,the ecological impact of plants on soil is through the utilization of soil fertility,soil fixation,accumulation and decomposition of biomass of plant types,which leads to different dynamic changes of soil nutrients on time and space scales.This interaction effect varies in different environments,and seasonal factors play an important role in the vegetation-soil relationship.Mountain ecosystem is an important part of terrestrial ecosystem,and alpine forest ecosystem is one of the components of alpine ecosystem.Alpine forest vegetation is closely related to soil and is sensitive to climate change,so it is an important part of studying vegetation-soil interaction in alpine ecosystem.Sejila Mountain is located in the alpine region,with high altitude and large span,and the vertical differentiation of vegetation and soil is obvious.It is a typical area to study the effect of vegetation-soil interaction under seasonal influence.Based on this,this study selected six forest types(Pinus armandii2560 m,Pinus densata 2897 m,Picea likiangensis var.linzhiensis 3380 m,Quercus aquifolioides 3510 m,Abies georgei var.smithii 3900 m,Juniperus saltuaria 4420 m)on different altitude gradients in the Sejila Mountain in the growing season and non-growing season soil p H value and nutrient content,and used stoichiometric methods to study and analyze the ecological stoichiometric characteristics of soil organic carbon(SOC),total nitrogen(TN),total phosphorus(TP),total potassium(TK)and the interaction between components.It has important theoretical and practical significance for revealing the nutrient cycling law and nutrient limitation characteristics of the forest ecosystem in Sejila Mountain,and provides data and theoretical support for the subsequent research on stoichiometric characteristics such as soil microflora and the protection of forest ecosystem.The results are as follows :(1)In general,the soil nutrient content and stoichiometric ratio of the six forests were different in different seasons.In the growing season,the p H value was 5.51,and the mean values of SOC content,TN content,TP content and TK content were 30.26,1.57,0.43 and 15.42 g / kg,respectively.In the non-growing season,the p H value was 5.53,and the mean values of SOC content,TN content,TP content and TK content were 33.59,1.67,0.42 and 16.68 g / kg,respectively.The p H value,SOC content,TN content and TK content showed that the non-growing season was greater than the growing season.TP content in growing season was higher than that in non-growing season.In the growing season,the average values of C : N,C : P,C : K,N : P,N :K and P : K were 18.78,74.44,2.19,3.92,0.11 and 0.03,respectively.In the non-growing season,the average values of p H value,SOC content,TN content,TP content and TK content were 19.82,74.79,2.18,3.69,0.11 and 0.03,respectively.C : N and C : P showed that the non-growing season was greater than the growing season,and C : K,N : P,N : K and P : K showed that the growing season was greater than the non-growing season.(2)Overall,p H value increased with soil depth,SOC content,TN content,C : P,C : K,N : P,N : K,P : K decreased with soil depth,TK content and C : N tended to be stable.Among them,the contents of C and N in the surface and deep layers were significantly different,and the soil nutrients showed surface aggregation characteristics,and the nutrient content decreased significantly with depth.(3)The changes of soil p H value,soil nutrient content and soil stoichiometry among different forests were inconsistent and had no obvious regularity.The stand had no significant effect on other values except TK,N : P and N : K(P < 0.05).(4)Compared with the national average level of soil C,N,P and K content,the contents of SOC,TN and TK in the forest soil of Sejila Mountain were at ’ medium ’ and above levels,and the soil TP was lower than the national level,indicating that the forest soil was significantly limited by P element.Affected by many factors,the soil nutrient content of different forest types in Sejila Mountain is different.In the management of Sejila Mountain forest area,we should pay attention to the supplement of P element in soil and strengthen the protection of forest vegetation in order to maintain forest productivity for a long time.