Contents And Stoichiometric Characteristics Of Carbon And Nutrient Elements In Leaf Litter,Roots And Soils In Subtropical Forest

The restoration and reconstruction of forest ecosystem has become an important theme of plantation development.In this study,mamanling Nature Reserve of Anhui Province and Moshan Experimental Forest Farm of Huiteng Forest Ecological Experimental Station in Hunan Province were selected as the research areas,and the important forest vegetation types of Chinese fir,Masson pine,walnut,Acuoak and Schima schima were selected as the research objects.In order to study the ecological stoichiometric change characteristics of soil,litter and root system,To reveal the law of nutrient cycle and restricted supply in its ecosystem.Based on fir,masson pine,walnut,German oak and schima superba as the research object,the application of ecological stoichiometry theory,USES the quantitative experiment on field sampling and analysis the method of combining with different forest soil,litter,root of carbon,nitrogen,phosphorus chemical metrological characteristics and other elements such as potassium,calcium,sodium,magnesium,iron,manganese of stoichiometric characteristics are studied,In order to provide scientific basis and reference for quantitative evaluation of ecological stoichiometry research of the above ecosystem,and to provide basic data and scientific support for ecological restoration and management of forest vegetation in the study area.The main results are as follows:（1）The average soil C content,N content and P content of different forest types in Anhui province were 36.06 g·kg^-1,2.89 g·kg^-1and 1.98 g·kg^-1respectively.Soil carbon,nitrogen and phosphorus contents were the highest in 0-10cm soil layer,and THE N content in 0-10cm soil layer of four forest types in Anhui Province was higher than the mean value of total N content in 0-10 cm soil layer in China.Except for walnut forest,the soil decreased first and then increased with the deepening of soil layer,other forest tree species decreased first and then increased with the deepening of soil layer.The average soil C content,N content and P content of different forest types in Hunan province were 20.96 g·kg^-1,1.85 g·kg^-1and 0.47 g·kg^-1respectively.Soil c,N and P contents were the highest in 0-10 cm soil layer,and schima superba and Masson pine soil showed a trend of first decreasing and then increasing with the deepening of soil depth.Soil C:N,C:P and N:P of different forest types in Anhui province were 12.72,28.00 and 2.18,respectively.Soil C:N,C:P and N:P of different forest types in Hunan province were 12.07,45.94 and 4.12,respectively.The variation trends of C:N,C:P and N:P in forest soil of different species were different.Plant soils of different forest types are mainly restricted by P,and N and P have highly dependent and coupling effects.（2）The average contents of K,Ca,Na,Mg,Fe and Mn in soil of different forest types in Anhui province were 3.50 g·kg^-1,1.64 g·kg^-1,1.28 g·kg^-1,1.28 g·kg^-1,5.31 g·kg^-1;The average contents of K,Ca,Na,Mg,Fe and Mn in different forest types in Hunan province were 7.07 g·kg^-1,0.62 g·kg^-1,4.48 g·kg^-1,2.72 g·kg^-1,6.43 g·kg^-1and 10.51 g·kg^-1,respectively.In the study,the soil potassium content of tree species in Anhui and Hunan provinces was lower than that of total soil potassium content in China(15-20 g·kg^-1).In the study area,the soil sodium content of different forest types had no significant difference among different layers（P>0.05）.The average magnesium content in the study area is1.08-1.49 g·kg^-1,which is significantly lower than the average level of 21 g·kg^-1in the earth’s crust and also lower than the average level of 3-25 g·kg^-1in most soils.In addition,iron content in the study area ranged from 9.43 to 26.84 g·kg^-1.There is a significant negative correlation between soil K content and soil Ca,Na,Mg content,and a significant negative correlation between soil Fe content,indicating that there is a complex coupling relationship between elements.（3）The average contents of K⁺,Ca²⁺,Na⁺and Mg²⁺in different forest types in Anhui province were 0.59 g·kg^-1,2.10 g·kg^-1,0.37 g·kg^-1and 2.84 g·kg^-1,respectively.The average contents of K⁺,Ca²⁺,Na⁺and Mg²⁺in different forest types in Hunan province were 0.10 g·kg^-1,4.08 g·kg^-1,0.27 g·kg^-1and 1.89 g·kg^-1,respectively.The K⁺,Ca²⁺,Na⁺and Mg²⁺contents of soil exchangeability in different forests decreased with the increase of soil depth,showing obvious characteristics of surface aggregation.The contents of Mg²⁺and Ca2+in different forest soils were significantly higher than those of other exchangeable cations,and were 3-4 times of those of other exchangeable cations.With the increase of soil depth,the change of soil exchangeable Na+content in different forests was roughly the same.The soil exchangeable Na+content of each forest has no significant difference with soil layer realization.（4）The average C,N and P contents of litter in Anhui province were 504.75 g·kg^-1,10.57 g·kg^-1and 0.64 g·kg^-1,respectively.The average C:N,C:P and N:P contents were52.17,815.01 and 16.14,respectively.The average C,N and P contents of cunninghamia lata litters in Hunan province were 479.15 g·kg^-1,12.85 g·kg^-1and 0.45 g·kg^-1,respectively.The average C:N,C:P and N:P contents were 39.08,1.89.26 and 29.99,respectively.The average contents of K,Ca,Na,Mg,Fe and Mn were 0.83 g·kg^-1,3.50 g·kg^-1,0.76 g·kg^-1,1.90 g·kg^-1,1.18 g·kg^-1and 0.39 g·kg^-1,respectively.The average contents of K,Ca,Na,Mg,Fe and Mn were 1.14 g·kg^-1,2.63 g·kg^-1,0.66 g·kg^-1,1.93 g·kg^-1,1.67 g·kg^-1and 0.29g·kg^-1,respectively.In addition,there was a very significant positive correlation between litter C and litter C:N and C:P values,and a very significant negative correlation between litter C and litter N:P values.There was a significant negative correlation between litter P and litter C:N and C:P values.（5）The average contents of C,N and P in fine roots in Anhui province were 493.16g·kg^-1,11.51 g·kg^-1and 0.72 g·kg^-1,respectively.The average values of C:N,C:P and N:P were 38.68,609.58 and 15.98,respectively.The average contents of C,N and P in fine roots of Cunningham fir in Hunan province were 443.30 g·kg^-1,10.16 g·kg^-1and 0.56g·kg^-1,respectively.The average values of C:N,C:P and N:P were 43.67,802.57 and 18.40,respectively.The average contents of K,Ca,Na,Mg,Fe and Mn in fine roots in Anhui province were 6.16 g·kg^-1,0.81 g·kg^-1,0.70 g·kg^-1,3.29 g·kg^-1,12.99 g·kg^-1and 0.22 g·kg^-1,respectively.The average contents of K,Ca,Na,Mg,Fe and Mn in fine roots in Hunan province were 6.08 g·kg^-1,0.78 g·kg^-1,0.69 g·kg^-1,2.42 g·kg^-1,13.07 g·kg^-1and 0.14 g·kg^-1,respectively.In addition,N content in fine roots was negatively correlated with C:N and C:P,P content was positively correlated with C:N,C:P and N:P,and C:P was positively correlated with C:N and N:P.The C,N and P contents of plant components in different forest types were as follows:litter>fine root>soil,and the C,N and P contents of plant components in different forest types were significantly different（P<0.05）.