Amiri, Fazel

Chaichi, M. R.

Tabatabai, T.

English

University of Kentucky

University of Kentucky UKnowledge International Grassland Congress Proceedings 21st International Grassland Congress / 8th International Rangeland Congress Assessment of Important Environmental Factors Affecting Agropyron trichophrum Establishment by Using an Ordination Method Fazel Amiri Islamic Azad University, Iran M. R. Chaichi University of Tehran, Iran T. Tabatabai Islamic Azad University, Iran 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/21/1-4/34 The 21st International Grassland Congress / 8th 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. 　 Multifunctional Grasslands in a Changing World 　 Volume Ⅰ 　 瞯 ]183　 瞯Grasslands/Rangelands Resources and Ecology ——— Ecology of Grasslands/RangelandsAssessment of important environmental factors affecting Agropyron trichophrum establishmentby using an ordination methodFazel Amiri ,１ M . R . Chaichi２ and T . Tabatabai ３１ Faculty Member o f Natural Resources , Islamic A z ad University Bushehr Branch , I ran . E‐mail : f amiri ＠ na .iut .ac .iramiri ＿ f az el＠ yahoo .com , ２ A ssoc . Pro f . o f Tehran University , College o f A gric . , Tehran , I ran .３ MS .c . Student o f Env ironmental Pollution , Islamic A z ad University Research and Science , Branch A hw az , I ran .Introduction Iran is the homeland of diverse plant and animal species . Our knowledge of the environmental factors affectingthese species and their distribution will help to develop more efficient range improvement plans . Plants growing in differentsites represent the climatic and topographic characteristics of their natural habitats ( Elinberg , １９９２ ) . Knowledge of thesecharacteristics will help to develop range improvement plans based on ecological demands of different plant communities( Escudero et . al . , ２０００ ) . For example , Allen et .al . , ( １９９５ ) found a significant correlation between soil and topographicproperties . These results indicated that there is a possibility to estimate site potentials from both topographic features andexisting plant communities . Similarly , EL‐Ghareeb and Shabana ( １９９０ ) investigated correlations between soil and vegetationcover characteristics . The effective factors on establishment and grow th of plant species were classified in two categories . Ourstudies built upon this earlier work .Materials and methodsStudy areaThe study area was located in Karchambu watershed , Faridan , ２００km west of Isfahan . The total karchambu watershed area isabout １１０００ hectares which geographically is located between ４９°５０′ and ５０°３６′ eastern latitudes and ３２°２′ and ３３°１１′ northernaltitudes . The minimum and maximum elevations from the sea level are ２３６０ and ３７１０m , respectively .Sampling methodsTo identify the most important edaphic factors contributing in A gropy ron trichophrum establishment and distribution in therange , １５ different sites with uniform cover of mentioned species were identified and selected . Quadrat samples of one squaremeter (１m２ ) were used to measure percent vegetation cover , species density and soil physical and chemical characteristics ontransacts representing the highest diversity of A gropy ron trichophrum ecotypes ( Mueller et al . , １９７４ ) . The least essentialsamples number for vegetations cover measurements in each site was calculated by the following equation (１) :N ＝ t２ × s２( 珔x × k) ２ (１) N : number of essential samples , T : t student value with n‐１ and ∞ ＝ ５％ , S : standard variation , X : meanvegetation coverN : primary sample number , K : Precision coefficient (１０％ ) . All the soil samples were transferred to the laboratory in separateplastic bags , where the pH value , EC as well as Na , K , Ca and Mg content were measured . Sodium absorption ratio wascalculated by the following equation (２) ( Miller and keenly , １９８６) .SAR ＝ Na/ [ Ca２ ＋ Mg２２] １ / ２ （２）Soil texture was measured by hydrometric method (Black , １９６５) . The relationship among all measured edaphic attributes withA gropy ron trichophrum establishment and distribution in all １５ range sites was explained by normal ordination grouping of CAcategories using CANOCO and PC‐ORD sof tware ( Ter Braak , １９８７ and １９８８) .Results The relationship of plant parameters with soil characteristics were identified by RDA( define) method . This method wasapplied to demonstrate these relationships graphically . The results of these analyses in １５ sites showed that there is strongcorrelation between two plant characteristic‐plant density and percent vegetation cover . The increment of these two parametersis exactly in direction of high density plant sites with over １４ , １０ , ５ , ２ , ６ and １２ which indicated the high presence ofA gropy ron trichophrum on these sites . The correlation between these plant parameters ( density and percent vegetation cover)are well indicated by the coefficient of correlation values . Soil characteristics like Ca content at soil A layer , sand , Cl , Mg , andNa at B and silt , clay Sp , EC , pH , and OC at A and B layers have no effects on A gropy ron trichophrum vegetation cover .Parameters like gavel percentage , Mg content and Na at A layer , and Cl at B as well as C / N and Ca content at both A and Blayers of the soil have a moderate effects on vegetation cover of A gropy ron trichophrum . Soil parameters like sand parentageand soil pH at soil a layer have a moderate effect on the vegetation cover while the same factors at B layer were the mosteffective ones on percent vegetation cover . The most important factors on A gropy ron trichophrum density were C/ N ratio andsoil pH at B layer . Among the selected soil parameters , C / N ratio , SAR , sand , gravel and calcium percentage at A layer andSAR , C/ N ratio and Cl at B layer had the highest positive correlation while Sp , pH , and EC parameters at A layer had thelowest correlation with plant parameters .

Assessment of Important Environmental Factors Affecting \u3cem\u3eAgropyron trichophrum\u3c/em\u3e Establishment by Using an Ordination Method

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Assessment of Important Environmental Factors Affecting \u3cem\u3eAgropyron trichophrum\u3c/em\u3e Establishment by Using an Ordination Method

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