Gao, Wenxing

Ma, Bin

Zhang, Gang

Zhang, Lili

Zhou, Zhiyu

English

University of Kentucky

University of Kentucky UKnowledge International Grassland Congress Proceedings 21st International Grassland Congress / 8th International Rangeland Congress Effects of Alfalfa Stand Age on Rhizosphere Soil Phosphorus in Saline Soil Wenxing Gao Lanzhou University, China Zhiyu Zhou Lanzhou University, China Lili Zhang Lanzhou University, China Bin Ma Lanzhou University, China Gang Zhang Lanzhou University, China 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/21/2-2/13 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. 瞯 ]358　 瞯 　 Multifunctional Grasslands in a Changing World 　 Volume Ⅰ 　Grasslands/Rangelands Resources and Ecology ——— Soil Quality and Plant NutritionEffects of alfalfa stand age on rhizosphere soil phosphorus in saline soilWenx ing Gao , Zhiyu Zhou 倡 ,L ili Zhang , Bin Ma , Gang ZhangCollege o f Pastoral A griculture Science and Technology , L anz hou University , L anz hou , China , Corresponding author 倡 ,E‐mail : z y z hou＠ lz u .edu .cnKey words : saline‐soil alfafa , rhizosphere soil , bulk soil , total P , available P , P fractionation , pHIntroduction Alfalfa is the main perennial legume forage in northwest China . Alfalfa stands can accumulate large amounts oforganic matter in the soil and improve physical and chemical characters of soil . Many researches have shown that growingalfalfa can greatly improve soil fertility . This study investigated effects of alfalfa stand age on rhizosphere phosphorus in salinesoil .Materials and methods The work was carried out at the Linze Grassland Faming Experimental Station ( Hexi Corridor , westernGansu province) . The elevation was １３９０m above sea level . The mean annul air temperature and annual precipitation were ７ .６℃ and １２１ .５ mm , respectively . Five plots (５５ × ３３m２ ) were planted with alfalfa in １９９８ (８ years old) , ２００１ ( ５ years old) ,２００２ (４ years old) ,２００３ (３ years old) and ２００４ (２ years old) . Ten well growing plants were randomly located within each sitein full flowering stage . The rhizosphere soil sample was collected by shaking method . Phosphorus contents in all samples weremeasured colourimetrically using the molybdenum blue method ( Murphy and Rilley , １９６２) on a UV /VIS Spectrometer . TotalP and available P were determined by sodium hydroxide digest method and Olsen method respectively . pH was detected by pHMeter . A modified Hedley摧s fractionation scheme described by Tiessen (１９９３) and Sui (１９９９) was used in P fractionation .Results There was no significant difference among stands in total P in rhizosphere soil and bulk soil . Available P in rhizospheresoil was higher than in bulk in all stands . Available P content in rhizosphere soil was greater in ５ years old stands than ２ yearsold stands but available P subsequently declined in ８ years old stands . In bulk soil , there were no significant difference ofavailable P content among ３ ,４ and ５ years old stands , but all of them were higher than in ２ years old stands . and then itdecreased remarkably in ８ years old stands . The pH in rhizosphere soil was lower than in bulk soil in all stands . The Pfractionation included organic P ( Po) fractionation and inorganic P ( Pi) fractionation . In Pi portion , the NaHCO３‐Pi , NaOH‐Pi and hot conc . HCl‐Pi ( HHCl‐Pi) contents in rhizosphere soil were significant higher than in bulk soil in all stands but therewere no significant difference in the H２O‐Pi and Ca‐Pi contents among stands of different age . With the increase in plant age ,all Pi fractions in rhizosphere and bulk soil increased except for the ８ years old stands , however , the NaOH‐Pi in rhizosphereand bulk soil decreased from ２ to ８ years old stands . In Po portion , NaHCO３‐Po and NaOH‐Po in rhizosphere were significanthigher than in bulk soil in all stands , but differences among HHCl‐Po contents were not significant . NaHCO３‐Po in rhizosphereand bulk soil decreased with the increase of plant age . The NaOH‐Po increased from ２ to ５ years old stands , but decreased in８ years old stands . There was no noticeable temporal change of HHCl‐Po in rhizosphere and bulk soil . The difference ofResidual‐P contents between rhizosphere and bulk soil was also not significant . With the increase in stand age , the Residual‐Pin both rhizosphere and bulk soil decreased .Conclusion Alfalfa stand age was a major driver of P form and P supply in rhizosphere soil in this saline system . The specificeffect on soil P differed depending on stand age and the P fraction examined .

Effects of Alfalfa Stand Age on Rhizosphere Soil Phosphorus in Saline Soil

https://uknowledge.uky.edu/cgi/viewcontent.cgi?article=2525&amp;context=igc

Effects of Alfalfa Stand Age on Rhizosphere Soil Phosphorus in Saline Soil

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