北京地區(qū)污水灌溉農(nóng)田若干特征研究.pdf

1、中國農(nóng)業(yè)大學碩士學位論文北京地區(qū)污水灌溉農(nóng)田若干特征研究姓名：楊華鋒申請學位級別：碩士專業(yè)：農(nóng)業(yè)水土工程指導教師：馮紹元20050601z叫日農(nóng)業(yè)人學壩|：學位論文AbstractAbstractThesewageirrigationdevelopmentinBeijingregioncanbedividedin4periods：beginning，increasingrapidlystabilization，decreasingThe

2、locationofsewagewaterirrigatingfarmlandhadawestnorthwestnorthsouth—southeastshiftprogressTheinitialareawasonlymorethan6667hm‘inthewestsuburb，thenitWasincreasedtoitsmaximum80，000hm‘inthelateof1980s，andnowitsharplyreducedt

3、oabout270130hm2asforthefollowingmainreasons：First，Beijing’slanduseconstlMctionhaschangedgreatlythesewageirrigationfarmlandwasoccupiedSecondly’Inordertoprotectemvironment，thefarmlandquondamlyirrigatedwithsewagewaterhasuse

4、dgroudwalerinrecently5yearsFinallytheplantingsystemswasalsotransferred，thecropfarmlandschangeintovegetablefieldsThesandyloamysoilwerefromtheexperimentalplotsofBeijingAcademyAgricultureandForestrySciencesandtheclayloamsoi

5、lwerefromBeijingDixingBeiyechangregion，theadsorptioncapacityofthetwosoilsontoCadmiumincreasedwithincreasingCadmiumconcentration，buttheadsorptionratedecreasedgraduallyForthisexperiments，theinfluencingfactorsofadsorptionin

6、cludedtheorganicmaRercontentofsoil，theclaycontentofsoil，temperatureandthesoiloriginalCadmiumconten!AddingtheorganicmaaertothesoilcouldenhancethesoiladsorptioncapabilitythesametotheclaycontentWhentheCadmiumconcentrationWa

7、sinarelativelyrange，thelessofthesoiloriginalCadmiumcontent，themoreofthesoiladsorptioncapabilityInaddition，theCadmiumadsorptionprocessesofthesandyloamysoilwasendothermic，howevertheclayloamysoil’SWaSexothermicAt25“(2and5“C

8、。whentheCadmiumconcentrationrangedfrom01—10mgL1，HenryformulacoulddescribetheCadmuimadsorptionprocesseswell，whentheCadmiumconcentrationrangedfrom50～900mgL1，LangmuirformulacoulddoitwellWhentheCadmiumconcentrationrangedfrom

9、O1900ragL‘，Langmuirformulacouldalsoworkwell，what’smore，theCadmiummaximumadsorptioncapatilitycouldbecalculated，itis5000mgkg“1Thesoil，whichWaSfromtheBeijingShijingshanYamenkouregion，CadmiumreleasingWasadynamicreversiblepro

10、cess04hWaSafastreleaseprocess，6～24hWasarelativelyslowoneThesecondreleaSeprocessCadmiumconcentration’SpeakvalueWasalsosmallerthanthefirstoneThefirstreleaSekineticprocesscouldbedescribedbyElvoichequationThemodifiedFreundli