Soil Total Organic Carbon, δ13c Values and Their

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1 Interntionl Congress on Environmentl Modelling nd Softwre Brighm Young University BYU ScholrsArchive 5th Interntionl Congress on Environmentl Modelling nd Softwre - Ottw, Ontrio, Cnd - July 2010 Jul 1st, 12:00 AM Soil Totl Orgnic Cron, δ13c Vlues nd Their Responses to the Soil Core Trnsferring Experiment from High- to Low-elevtion Forest long Nturl Altitudinl Trnsect of Old Temperte Volcnic Forest Soils Zhng Xin-Yu Meng Xin-Jing Fn Jin-Jun Go Lu-Peng Sun Xio-Min Follow this nd dditionl works t: Xin-Yu, Zhng; Xin-Jing, Meng; Jin-Jun, Fn; Lu-Peng, Go; nd Xio-Min, Sun, "Soil Totl Orgnic Cron, δ13c Vlues nd Their Responses to the Soil Core Trnsferring Experiment from High- to Low-elevtion Forest long Nturl Altitudinl Trnsect of Old Temperte Volcnic Forest Soils" (2010). Interntionl Congress on Environmentl Modelling nd Softwre This Event is rought to you for free nd open ccess y the Civil nd Environmentl Engineering t BYU ScholrsArchive. It hs een ccepted for inclusion in Interntionl Congress on Environmentl Modelling nd Softwre y n uthorized dministrtor of BYU ScholrsArchive. For more informtion, plese contct scholrsrchive@yu.edu, ellen_mtngelo@yu.edu.

2 Zhng Xinyu et l Soil totl orgnic cron, δ 13 C vlues nd their responses to the soil core trnsferring Soil Totl Orgnic Cron, δ 13 C Vlues nd Their Responses to the Soil Core Trnsferring Experiment from High- to Low-elevtion Forest long Nturl Altitudinl Trnsect of Old Temperte Volcnic Forest Soils ZHANG Xin-Yu, MENG Xin-Jing,, FAN Jin-Jun, GAO Lu-Peng,c, SUN Xio-Min *. Key Lortory of Ecosystem Network Oservtion nd Modeling, Institute of Geogrphic Sciences nd Nturl Resources Reserch, Chinese Acdemy of Sciences, Beijing zhngxy@igsnrr.c.cn * corresponding uthor: sunxm@igsnrr.c.cn. Shenyng Agriculturl University, Shenyng , Chin c. Ntionl Science nd Technology Infrstructure Center, Beijing , Chin Astrct: In this study, the responses of soil orgnic cron nd δ 13 C vlues to soil wrming were conducted y relocting intct soil cores from high- to low-elevtion forests for one yer long nturl ltitudinl trnsect in the northern slope of Chngi Mountin. As expected, the soil-core reloction cused significnt increse in soil temperture ut mde no significnt effect on soil moisture. The results showed tht fter one yer incution, soil reloction significntly decresed TOC contents, nd δ 13 C decresed. Person correltion nlysis demonstrtes tht TOC content ws negtively relted to soil temperture ut positively relted to soil moisture. After one-yer simulted wrming experiment, δ 13 C vlues in ulk soils reduced y Furthermore, the decreses in the size frctions <63 μm were lrger thn those in the size frctions μm. Key words: Soil-core reloction experiment; Old temperte volcnic forest soils; Soil orgnic cron species; δ 13 C;Soil prticle-size frctions 1 INTRODUCTION Over the next 100 yers, nthropogeniclly induced climte wrming from the production of greenhouse gses is hypothesized to increse glol men nnul temperture y (IPCC,2001). However, ecosystem-level response of soil orgnic cron to glol wrming is difficult to e defined from simple direct responses of ecosystem components. Mny different experimentl pproches hve een used to study the potentil impcts of climte chnge on terrestril ecosystems, including controlled-climte lortory

3 Zhng Xinyu et l Soil totl orgnic cron, δ 13 C vlues nd their responses to the soil core trnsferring studies, experimentl field mnipultions using plstic enclosures, uried heting cles, nd infrred rditors (Hrt nd Perry, 1999; Hrt, 2006). Using nturl temperture grdients cused y chnges in ltitude or spect coupled with direct mnipultion (soil or plnt-soil trnsplnt) lso hve een used s surrogte experimentl pproches which my provide powerful nd cost-effective nd convenient tool for ssessing the potentil impct of climte chnge on terrestril ecosystems (Hrt nd Perry, 1999; Hrt, 2006). The forest soil cron pool ccounts for out 73 % of the soil cron pool (Post nd Emnuel, 1982). Thus, reltively smll chnge of forest soil cron pool my hve n importnt role in regulting the glol cron lnce. The isotopes of cron provide mens to study soil cron dynmics (Bird et l., 1996; Bird et l., 2004).Understnding soil orgnic cron responses to the glol wrming will help to revel the dynmics nd mechnism of soil cron pool (Gong et l., 2008; Lik et l., 2009 ). Temperte forests occupy lrge re in northestern Chin where effects of projected climtic wrming on terrestril ecosystems re significnt. Understnding the soil orgnic cron responses to the temperture in this re is importnt for improving soil cron mngement of forest ecosystem. However, our knowledge is limited to the effect of glol wrming on dynmics of different soil cron frctions in old temperte volcnic forest soils of Chngi Mountin. In this study, surfce volcnic minerl soils under three typicl old temperte forest stnds long ltitudinl trnsect of Chngi Mountin were smpled nd relocted intct soil cores from high- to low-elevtion forests were deployed, to study the effects of forest types, temperture, nd other environmentl conditions long ltitudinl trnsect on soil TOC nd δ 13 C vlues. The results cn improve the understnding for the response of cron dynmics in temperte soils to vrying vegettions nd temperture. 1. METHODS 1.1Study site The study site ws locted t ltitudes from 740 to 1996 m on the northern slope of Chngi Mountin, Northestern Chin (42 24 N, E). The forest ecosystem of the Chngi Mountin is the most typicl mountin temperte forest ecosystem in estern Asi, with verticl zonl distriution of vegettion resulted in vried topogrphy, wether, soil nd other nturl conditions in Chngi Mountin (Wng et l., 2004). Recent smll-scle volcno eruptions occurred in 1702 nd very lrge scle eruption occurred during (Liu et l. 1992; Zho 1981). Three nturl temperte forests in nturl verticl distriution long the northern slope were considered to e rod-leved Koren pine mixed forest, spruce-fir forest nd Ermn s irch forest. Brod-leved Koren pine forest (elow 1100 m ltitude) t the foot of Chngi Mountin is typicl nturl coniferous-ltifolite mixed forest whose dominnt tree species re Pinus Koriensis, A. mono Mxim, T. murensis Rupr, Frxinus mndshuric Rup nd Quecusmongolic. The dominnt tree species in spruce-fir forest (ltitude m m) re Pice koriensis nd P. jezoensis. Ermn s irch forest (ltitude m m), which constitute the

4 Zhng Xinyu et l Soil totl orgnic cron, δ 13 C vlues nd their responses to the soil core trnsferring peculir forest lndscpe of sulpine elts, is the forest-line vegettion dominted y single rorel tree species of Betul ermnii (Wng et l., 2004). The climte is continentl temperte climte with ovious verticl climte-chnging fetures. The men nnul temperture is out nd the men nnul precipittion is out 700 mm t the rod-leved Koren pine forest zone, out nd out 800 mm t the spruce-fir forest zone, nd out nd mm t the Ermn s irch forest zone (Wng, et l., 2004). There is ovious verticl zonlity of soil on the northern slope of Chngi Mountin. With the order of from top to ottom: mountin soddy forest soil (ltitude m), mountin rown conifer forest soil (ltitude m) nd mountin drk rown forest soil (elow 1100 m ltitude (Wng et l., 2004). These soils elong to Andosols y Food nd Agriculture Orgniztion soil clssifiction (Xu et l., 2007). 1.2 Experimentl design nd field incution On June 8 th 2007, fifteen 3 3 m plots were estlished rndomly within three forest types, i.e., rod-leved Koren pine forest, drk coniferous forest nd ermn s irch forest with <3º slope nd well drined hydrologicl conditions in ech plots. Five estlished plots in ech forest type were out 2 m distnce prt, three of the plots were selected s control nd two s soil core smpling or incution site. Eight (in one drk coniferous forest plot) or sixteen (in two ermn s irch forest plots) intct soil cores were removed using 30-cm inner dimeter 30-cm long, thin-wlled polyvinyl chloride (PVC) pipe tht hd een shrpened t one end. The intct soil cores were relocted from the high- to the low-elevtion forest plots for one-yer field incution. Sixteen soil cores from ermn s irch forest were plced in one spruce-fir forest plot nd one rod-leved Koren pine forest plot, respectively. Eight soil cores from spruce-fir forest plot were plced in one rod-leved Koren pine forest. 1.3 Smpling Six soil smples, t ech depth of 0-10 cm nd cm, were collected from ech control plot y uger, then pooled for one soil smple in June 2007, June, July nd August of 2008, totl of 72 soil smples from control plots were smpled. In June, July nd August of 2008, incution soil cores were smpled y uger t ech depth of 0-10 cm nd cm, 3 soil cores of ech forest type were selected ech time, totl of 54 soil core smples were selected. The fresh soil smples were seprted from fine seeds, sieved through 2 mm mesh, then put into seled hop-pockets nd kept t 4. In June 2007, three cm rcket of decomposed nd undecomposed litter were collected from ech control plot, then pooled for one litter smple, totl of 18 litter smples were selected., then dried t 70 C for 24 h to mke powder for use. 1.4 Methods of mesurements The soil tempertures of plots nd soil cores were mesured in situ y SN-digitl

5 Zhng Xinyu et l Soil totl orgnic cron, δ 13 C vlues nd their responses to the soil core trnsferring thermometer t depth of 5 cm during 9:00-10:00 m nd 2:00-3:00 pm on June 9 th, July 13 th nd August 12 th of Soil moisture ws determined y mss loss on drying oven. The totl orgnic cron contents were determined y rpid dichromte oxidtion of dried nd sieved (0.28 mm) smples. The soil smples were seprted into 3 frctions (<63 μm, μm, μm, >1000 μm) y wet sieved method nd the <2 μm frction ws seprted from the 2-63 μm frction y differentil settling in wter. Recoveries from this procedure were >95 % y weight in ll cses. After drying nd determintion of the proportion of ech size frction, soils were prepred for 13 C-isotope nlysis. Frctions >63 μm were crushed efore further nlysis. The 13 C vlues of the soils were mesured using n isotope rtio mss spectrometer (Thermo Finnign MAT253). The smples were comusted to CO 2 in n elementl nlyzer (Flsh EA 1112 Series) nd introduced to the mss spectrometer in continuous flow mode. The 13 C vlues re reported s per mil (prts per thousnd; ) devitions from the PDB stndrd. IAEA-CH-3 ws used s reference mteril. 1.5 Sttisticl nlyses In this study, the dt were sttisticlly nlyzed y SPSS 11.0 softwre for windows. Prmetric sttistics of ANOVA nlysis ws crried out to test for significnt differences of soil properties mong forest types nd wrming experimentl tretments t p <0.05. If the effects of forest types nd wrming experimentl tretments were significnt, men seprtions were chieved using protected lest significnt difference (LSD) test t p <0.05. Person s correltion nlysis ws performed to explin reltionships mong soil orgnic cron, soil temperture nd soil moisture. 2 RESULTS 2.1 Soil temperture nd soil moisture in the soils nd trnsferred soil cores long nturl ltitudinl trnsect The soil tempertures of the 5 cm depth were significntly different mong the three forest type, vried s rod-leved Koren pine forest (PB)>spruce fir forest (SF)> ermn s irch forest (EB) (Fig. 1). Soil tempertures in low-elevtion incuted soil cores were not sttisticlly different from those in mient control plots during 2008.The soil moisture of the 0-20 cm lyers in EB ws significntly lrger thn tht in SF nd PB. The soil moisture ws lrger in rod-leved Koren pine forest thn tht in spruce-fir forest ut the difference ws not significnt (Fig. 1). Over yer period, wter moisture ws lso sttisticlly similr mong trnsferred soil cores nd mient control plots. As expected, the soil core reloction experiment cused significnt increse in soil temperture ut mde no significnt effect on soil moisture.

6 Zhng Xinyu et l Soil totl orgnic cron, δ 13 C vlues nd their responses to the soil core trnsferring Soil temperture ( ) c c June 9 th July 13 rd August 12 th c Soil moisture (%) June 9 th July 13 rd August 12 th PB SF EB SF-P B EB-SF EB-PB Figure 1. Soil tempertures in 5 cm depth nd soil moistures in 0-20 cm lyers in the three typicl forest soils nd the trnsferred soil cores in 2008 The error r represents the stndrd error (n=3), the tretments with sme letters re not significnt t p<0.05. DC-PB: the soil cores of drk coniferous forest trnsferred to rod-lef Koren pine forest; EB-DC: the soil cores of ermn s irch forest trnsferred to drk coniferous forest; EB-PB: the soil cores of ermn s irch forest trnsferred to rod-leved Koren pine forest. The sme elow. 2.2 Soil TOC contents in the three nturl forest nd trnsferred soil cores long nturl ltitudinl trnsect The TOC contents incresed with elevtion increse long nturl elevtion grdients, vried s EB>SF>PB. Surfce minerl soil (0-10 cm) hd significntly higher men TOC contents thn susurfce soil (10-20 cm). In 0-10 cm soil lyers, the TOC contents were significntly lrger in EB thn those in SF nd PB, ut the TOC contents of SF nd PB were not significntly different. In cm soil lyers, the TOC contents of the three forest types were significntly different(tle 3).After one yer incution, soil reloction resulted in TOC content decrese in SF-PB, EB-SF nd EB-PB soil cores in 0-10 cm nd cm lyers, nd especilly the effect on cm lyers were significnt (Tle 3). Person correltion nlysis indicted tht TOC content in 0-10 cm soil lyer ws significntly negtively relted to soil temperture in 5 cm soil lyer (r=-0.549,p<0.01) ut TOC content ws positively relted to soil moisture (r=0.884, p<0.01). Tle 1 Men concentrtions of TOC y different forest type nd tretment in 2008 Tretments/TOC PB SF SF-PB EB EB-SF EB-PB (g kg -1 ) 0-10 cm 45.8±0.7 c 61.6±9.7 c 55.6±6.2 c 91.8± ± ± cm 10.9±0.8 d 28.1±4.9 c 14.3±0.8 d 48.9± ± ±2.8 For different smll letters re significnt t p<0.05 in sme row (LSD).TOC, soil orgnic cron. TOC contents under the three typicl forests incresed significntly with the incresing ltitude. Person correltion nlysis demonstrtes tht TOC content ws negtively relted to soil temperture ut positively relted to soil moisture. Our study showed

7 Zhng Xinyu et l Soil totl orgnic cron, δ 13 C vlues nd their responses to the soil core trnsferring tht the elevtion increse, ccompnied y soil temperture decrese nd soil moisture increse, resulted in TOC content increse. This ws consistent with the result from centrl Oregon Cscde Mountins, USA (Hrt nd Perry, 1999). Hrt nd Perry (1999) found tht high-elevtion old-growth forest soils hd higher cron nd nitrogen storge thn their low-elevtion nlogues primrily ecuse low tempertures limit net cron nd nitrogen minerliztion rtes t higher elevtion. 2.3 Soil δ 13 C vlues in the three nturl forest nd trnsferred soil cores long nturl ltitudinl trnsect The δ 13 C vlues were enriched downwrd the profile through litter nd soil lyers (Figure 2). The δ 13 C vlues rnged from to in undecomposed nd decomposed litters nd rnged from to in 0-10 cm nd cm soil lyers. The δ 13 C vlues vried s SF>PB>EB in litters nd vried s EB>PB>SF in soil lyers. Person correltion nlysis demonstrted tht δ 13 C vlues were negtively relted to soil temperture (r=-0.682, p <0.05). In generl, the δ 13 C vlues were higher in corse-textured soils nd lower in fine-textured soils (Figure 3). The verge δ 13 C vlue for size frctions <63μm ws etween 0.6 nd 0.8 greter thn the verge δ 13 C for size frctions μm. Furthermore, the verge δ 13 C vlue for size frctions μm were enriched out 0.6 in cm soil lyers reltive to the 0-10 cm soil lyers δ 13 C ( ) PB SF EB undecomposed litter decomposed litter 0~10cm soil lyer 10~20cm soil lyer Figure 2 δ 13 C vlues in the three typicl forest soils nd litters in June (n =3, the error r represents the stndrd error) ulk soil δ 13 C ( ) >63 μm 2~63 μm <2 μm δ 13 C ( ) ulk soil >63 μm 2~63 μm <2 μm SF SF-PB EB EB-SF EB-PB 0~10 cm SF SF-PB EB EB-SF EB-PB 10~20 cm Figure 3 δ 13 C vlues of soils nd prticle-size frctions in the three typicl forest nd the trnsferred soil cores in August Trnsfer of high-elevtion soil cores to the low elevtion site resulted in decrese trend in δ 13 C vlues compred with vlues mesured in control plots (Figure 4). The

8 Zhng Xinyu et l Soil totl orgnic cron, δ 13 C vlues nd their responses to the soil core trnsferring ulk soil δ 13 C vlues in the soil cores of SF-PB, EB-SF nd EB-PB were depleted out reltive to the control plot. In SF-PB nd EB-SF soil cores, the δ 13 C vlues depleted more in size frctions <63 μm thn in μm. In SF-PB, the δ 13 C vlues depleted out for size frctions <63 μm in reltive to those in control plots nd depleted out for size frctions μm in reltive to those in control plots. In cm of EB-SF soil cores, the δ 13 C vlues depleted out 1.0 for size frctions <63 μm in reltive to those in control plots nd depleted out 0.2 for size frctions μm in reltive to those in control plots δ 13 C ( ) PB SF EB δ 13 C ( ) PB SF EB >1000 μm 500~1000 μm 63~500 μm 2~63 μm <2 μm 0~10 cm >1000 μm 500~1000 μm 63~500 μm 2~63 μm <2 μm 10~20 cm Figure 4 δ 13 C vlues of orgnic cron in prticle-size frctions of the Chngi Mountin forest soils in August 2008 Bird et l (2003) suggested tht in the presence of fine minerls, the trend ws to higher δ 13 C vlues due to the stiliztion of the products of microil decomposition y fine minerls. Vnhl et l (2007) suggested tht climtic wrming will ccelerte especilly the decomposition of the lrge pool of old soil cron in these fields. On the other hnd, Conen et l. (2006) did not find differences etween young nd old soil cron in similr methods. In the trnsferred soil cores, the δ 13 C vlues depleted more in size frctions <63 μm in reltive to those in size frctions μm. Since the old cron is stored in the fine size frctions, our results were in greement with.the results from Vnhl et l (2007). 4 CONCLUSIONS The results showed tht under nturl conditions the contents of TOC were lrgest in EB, moderte in SF, nd smllest in PB. Person correltion nlysis demonstrtes tht TOC content ws positively relted to soil moisture. After one yer incution, soil reloction significntly decresed TOC contents nd decresed δ 13 C vlues especilly in <63 μm size frctions. The results my suggest tht climtic wrming will ccelerte especilly the decomposition of old soil cron in fine size frctions. Acknowledgments The study ws funded y the Ntionl Nturl Science Foundtion of Chin (Nos , ) nd Key project of Chinese Acdemy of Sciences knowledge

9 Zhng Xinyu et l Soil totl orgnic cron, δ 13 C vlues nd their responses to the soil core trnsferring Innovtion Progrm (No.KZCX2-YW ). We thnk the Chngi Mountin Forest Ecosystem Reserch Sttion for the support of estlishing the field plots. We lso thnk G H Di, L J Xu, nd others for ssistnce in the field nd lortory. REFERENCES Bird, M.I., A.R. Chivs, J. Hed, A ltitudinl grdient in cron turnover times in forest soils, Nture, 381, ,1996. Bird, M. I., E.M. Veenendl, J.J. Lloyd, Soil cron inventories nd δ 13 C long moisture grdient in Botswn, Glol Chnge Biology, 10, , Conen, F., J. Leifeld, B. Seth et l., Wrming minerlizes young nd old cron eqully, Biogeosciences, 3, , Gong, W., T.X. Hu, J.Y. Wng, et l., Soil cron pool nd fertility under nturl evergreen rod-leved forest nd its rtificil regenertion forests in Southern Sichun Province, Act Ecologic Sinic, 28(6), ,2008. Hrt, S.C., D.A. Perry., Trnsferring soils from high- to low- elevtion forests increses nitrogen cycling rtes: climte chnge implictions, Glol Chnge Biology, , Hrt, S.C, Potentil impcts of climte chnge on nitrogen trnsformtions nd greenhouse gs fluxes in forests: soil trnsfer study, Glol Chnge Biology, 12, , IPCC. Intergovernmentl pnel on climte chnge, Climte chnge 2001: the scientific sis. In: J.T. Houghton, et l, (eds). Contriution of working group I to the third ssessment report of the IPCC. Cmridge: Cmridge University Press, Lik, R., K.Kumr, D.K. Ds, O.P. Chturvedi, Lile soil orgnic mtter pools in clciorthent fter 18 yers of fforesttion y different plnttions, Applied Soil Ecology, 42, 71-78, Post, W.M., W.R.Emnuel., Soil cron pools nd world life zones, Nture, 298, , Vnhl, P., K. Krhu, M. Tuomi, et l., Old soil cron is more temperture sensitive thn the young in n griculturl field, Soil Biology & Biochemistry, 39, , Wng, M., Q.R.Li, D.M Xio,et l., Effects of soil temperture nd soil wter content on soil respirtion in three forest types in Chngi Mountin, Journl of Forestry Reserch, 15, , Xu, X. K., L. Hn, Y. S. Wng, et l., Influence of vegettion types nd soil properties on microil iomss cron nd metolic quotients in temperte volcnic nd tropicl forest soils, Soil Science nd Plnt Nutrition, 53, , 2007.