Funk, R.

Hoffmann, C.

English

University of Kentucky

University of Kentucky UKnowledge International Grassland Congress Proceedings XXI International Grassland Congress / VIII International Rangeland Congress Effects of Grazing on Wind Driven Matter Fluxes in the Xilingele Grassland, Inner Mongolia C. Hoffmann Zalf Muencheberg, Germany R. Funk Zalf Muencheberg, Germany Follow this and additional works at: https://uknowledge.uky.edu/igc  Part of the Plant Sciences Commons, and the Soil Science Commons This document is available at https://uknowledge.uky.edu/igc/21/10-2/39 The XXI International Grassland Congress / VIII International Rangeland Congress took place in Hohhot, China from June 29 through July 5, 2008. Proceedings edited by Organizing Committee of 2008 IGC/IRC Conference Published by Guangdong People's Publishing House This Event is brought to you for free and open access by the Plant and Soil Sciences at UKnowledge. It has been accepted for inclusion in International Grassland Congress Proceedings by an authorized administrator of UKnowledge. For more information, please contact UKnowledge@lsv.uky.edu. 瞯 ]278　 瞯 　 Multifunctional Grasslands in a Changing World 　 Volume Ⅱ 　Grasslands/Rangelands Production Systems——— Integration of Crops , Forage and Forest SystemsEffects of grazing on wind driven matter fluxes in the Xilingele grassland , Inner MongoliaC . Ho f f mann , R . FunkInstitute o f Soil L andscape Research , Zal f Muencheberg , Ebersw alder Strasse 84 , 15374 Muencheberg , Germany . Email :ho f f mann＠ z al f .deKeywords :wind erosion , dust storms , grazing intensity , nutrient balance , MAGIM‐project .Introduction Wind erosion and dust storms are common phenomena in the Xilingele region ( Inner Mongolia ) and contributeconsiderably to the redistribution of organic and mineral material in the ecosystem grassland . Fine material deposited by duststorms since long , which is reflected in the grain size distribution of the upper layers of the local loess soils . Activated by anincreasing grazing pressure during the last decades , dust emission by local wind erosion had become an important opposingprocess . Still in the １９８０s the Xilingele region was presented as one of the most representative and best‐preserved grasslands ofInner Mongolia ( Li et al . １９８８) . Since the １９９０s , land degradation induced by overgrazing had become very serious ( Li et al .１９９７ ) . The main functions of the grassland ecosystems consequently have become disturbed and the region is endangered toshif t from a natural dust sink to a potential dust source . The objective of this study was to identify the effect of grazingintensity on the wind borne carbon and nitrogen flux .Material and methods The measurements were made in the spring of ２００５ and ２００６ about ７０ km to the south of the districtcapital Xilin Hot . Enclosures with defined grazing intensities were used and grouped in ungrazed ( ０ ewes per ha ) , lightlygrazed ( ＜ １) , moderately grazed (１‐２) and heavily grazed ( ＞ ２) . To identify the effect of grazing on the grass conditions thespatial distribution of vegetation height and plant coverage were measured within the enclosures . Dust emission and depositionwere measured with MWAC poles (�Modified Wilson And Cooke") and DDS (�Dust Deposition Samplers") , which arecommon trap systems to quantify wind erosion ( Zobeck et al . , ２００３ ; Goossens ２００５) . Up to ２３ MWAC poles with four to fivetraps at heights between １３ and １４０ cm and １３ DDS were placed in the enclosures . The Corg and Nt contents of the trapped dustwere determined on a CNS ２０００ LECO‐Analyzer .Results The sediment contents of Corg and Nt were similar in both years ( on average ３６ .２ mg C g‐１ and ３ .３７ mg N g‐１ ) andaround ５０ ％ higher compared to average soil contents . Thus , the C‐and N‐balance is determined by the balance of dustmaterial or the intensity of dust storms , finally . The dust deposition of dust storm sediments at ungrazed sites was ２ ‐５ timeshigher than at heavily grazed sites . Local wind erosion was only measured at grazed sites , which were partly net dust emitters .The critical vegetation height , in which dust deposition and dust emission were in equilibrium , was between ４ and ９ cm ( ＝moderate grazing ) . Heavy grazing resulted in an annual loss of １７ ‐１３４ kg Corg ha‐１ and １ .５ ‐１２ .４ kg Nt ha‐１ . Lightly grazedsites gained ７ ‐４０ kg Corg ha‐１ and ０ .７‐６ .６ kg Nt ha‐１ per year . The largest matter gain was measured at ungrazed sites with upto １０５ kg Corg ha‐１ and ９ .８ kg Nt ha‐１ per year . Caused by stronger dust storms in ２００６ both , the dust deposition at ungrazedsites and the dust emission at heavily grazed sites were up to five times higher compared to ２００５ .Conclusions In the Xilingele region , grazing intensity has a major effect on the matter balance by wind erosion processes . Notonly the loss of nutrients increased exponentially , but also the gain by dust storm sediments was significantly reduced withincreasing grazing intensity . The annual variation of wind erosion processes showed that the processes could be much higher invery dry and windy years .ReferencesGoossens , D . (２００５) . Quantification of the dry aeolian deposition of dust on horizontal surfaces : an experimental comparisonof theory and measurements . Sedimentology , ５２(４) , ８５９‐８７３ .Li , B . , Yong , S . , Liu , Z . (１９８８) . The vegetation of the Xilin river basin and its utilization . In : Inner Mongolia GrasslandEcosystem Research Station , ８４‐１８３ . Beijing . ( Chinese with English abstract) .Li , B . , Li , Q .F . , Yang ,C . (１９９７) . International Symposium on Grassland Management in the Mongolian Plateau . Beijing .Zobeck , T .M . , Sterk , G . , Funk , R . , Rojot , J .L . , Stout , J .E . , Van Pelts , R .S . ( ２００３) . Measurement and data analysismethods for field‐scale wind erosion studies and model validation . Earth Sur f ace Processes and L and f orms , ２８(１１) , １１６３‐１１８８

Effects of Grazing on Wind Driven Matter Fluxes in the Xilingele Grassland, Inner Mongolia

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Effects of Grazing on Wind Driven Matter Fluxes in the Xilingele Grassland, Inner Mongolia

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