Changes Of Eco-stoichiometric Characteristics Of Drainage Peatland And Its Influencing Factors

Drainage is an important way of interference in peatland ecosystem,resulting the heterogeneity of community structure over a long period of time.While it is the nutrient change,material and energy flow in space as time going.Therefore,system nutrient status and its characteristic are important indicators to diagnose and repair the effects on ecosystems.Baijianghe peatland status in jilin province Jingyu Baijianghe village,is the development of peatland in the mountain valley basin.We study the Baijianghe peatland that drainages since 20c80 s,compare the ground vegetation,litter,soil profile and microbial nutrient characteristics between natural and drainage area,combining with other environmental indicators such as water level,soil moisture,p H,to explore the nutrition coupling relationship between above and below ground,reveal the internal mechanism of C,N and P balance,diagnosis the nutrient status,grasp the stability of ecosystem carbon,providing realistic foundation data and theoretical support to the work restore the damaged peatland ecosystems.We got the main conclusions as below:1.Caldesia parnassifolia Par.has high ecological niche,formed a stable grass community structure in natural peatland;Environmental change makes the shrubs plants which have strong stability to replace the poor stability species.Growing rapidly and producing a greater productivity,the drainage peatland gradually evolved into a shrub community,with the dominate species Potentilla fruticosa Linn.,associated with Rhododendronsimsii Planch.Betula ovalifolia Ruprecht.Ledum palustre.,the species diversity decreased.And this community has obvious difference with typical herbaceous peatland2.Nutrient absorption,distribution,migration is plant's unique nutrient utilization strategy,the single elements distribution is different between different organs.Concentration in different organs of C?N?P has significant difference(p<0.01),and N,P is mainly concentrated in plant leaves,ratio of N elements in the herb and shrub leaves about 61%and 58%,P concentration in leaf accounted for about 63 except Sanguisorba tenuifolia Fisch,Menyanthes.C concentration in drainage peatland is higher,leaf N,P also has obvious concentration,P concentration was obviously higher than that of natural peatland.Elements concentration in different species of the same organ also has significant difference(p<0.01).3.Comparing the element concentration of shrub leaf stems root in natural and drainage peatland shows that drainage make significant changes in the same plant nutrient status,drainage peatland Potentilla fruticosa Linn.and Betula ovalifolia Ruprecht leaves,root C concentration increased significantly,N concentration in mixed each species organs,Potentilla fruticosa Linn.stem root concentration decreases,the root of reducing the most significant(p<0.01),less drainage peatland decreased 19 % Rhododendronsimsii Planch.of leaf and root,Betula ovalifolia Ruprecht stems was significantly lower than natural peatland,the leaf N concentration of Ledum palustre.root and stem of Betula ovalifolia Ruprecht increased slightly.P element changes affected by drainage is most obvious,is also the most universal,Potentilla fruticosa Linn.P concentration decreased significantly(p<0.01).4.Plant nutrient absorption is an effective way to improve nutrient utilization,maintain its nutrients,element concentration of plants during different growth cycles has a significant change,the Caldesia parnassifolia Par.C concentration increased first,then decrease,N,P concentration was obvious decreasing,the decline of N elements in the process of reducing 43 %,litter P reduce about 56.25 %,no nutritional enrichment phenomenon in root;Leaves of Potentilla fruticosa Linn.in the process of decay,C and P concentration decreased significantly,N concentration is decrease after increase first.C concentration of stem and root significantly reduce at the end of growing season,N concentration of stems decrease significantly,while that of root increase obviously,stem of P concentration increased from 0.24 to 0.44 g/kg,root increased from 0.23 to 0.71 g/kg,nutrient retention phenomenon is obvious.5.Stoichiometric cascade shows natural and drainage peatland plant leaf N:P > 16,suggests system is phosphorus limitation,and drainage strength phosphorus limited.Natural and drainage peatland soil profile C:N has obvious difference in the surface layer of 50 cm,natural peatland 0?20 cm,with an average of 17.74 drainage peatland of 25-50 cm,18.75,shows that horizon has a higher decomposition speed,soil mineralization faster.The depth below 20 cm in natural peatland,50 cm in drainage peatland,C:N smooth trends and numerical phase close to two kinds of condition.C:P and N:P in 10?25 cm,natural peatland slightly is higher than the drainage peatland,drainage peatland is higher than natural peatland in 25?50 cm.Correlation analysis results show that on the horizon C,N has significant correlation(p<0.05),C,N and P is negative correlation,drainage peatland C and P are significantly negative correlation(p<0.05).6.Soil microbial results show that the relatively stable natural peatland soil microbial biomass carbon decreases with depth deepening,and the drainage peatland below 50 cm overall conforms to the basic law,but volatile;In the active layer,MBC is higher,QMBC shows that the horizon of nutrient conversion efficiency is high,which has strong ability of decomposition.The change of soil moisture caused by drainage is the dominant factor of habitat change and other environmental factors on the response of drainage is one of the important factors affecting soil nutrient release.C,N,P concentration of Natural and drainage peatland ecosystem and its ecostoichiometric characteristics has obvious difference,the change of soil physical and chemical properties caused by water level change is the leading factor.Second,litter quality changes induced by the vegetation succession is an important factor that nots allow to ignore.This study could be used to grasp the Baijianghe peatland ecosystem nutrient status,provide the basis data and theoretical support for the degradation of peatland ecosystem restoration...