The Preliminary Study Of Organic Selenium Transformation In Different Soils

Selenium is a trace element and it’s necessary for the growth of humans and animals. Only organic selenium is the safety selenium source. Organic selenium can be translated into effective selenium in soil to provide a steady stream of selenium for plant growth. But organic selenium transformation mechanism in soil has no clear answer. By studying the transformation of exogenous and endogenous two different organic selenium source in soil, and to explore the transformation mechanism of soil organic selenium in different soils. Then through the culture of different selenium content soil to study the change rule of soil selenium fraction variation, analysis the influence of the different soil physical and chemical properties on soil selenium fractions, provide a reference basis for organic selenium conversion mechanism. The following main results obtained:1. In the experiment, leaf and root dry weight increased respectively by 10.7 and 32.7 percent compared with the control treatment, when selenium-pakchoi(SP) applied to the soil; the selenium content of pakchoi shoot is 2.2 ± 0.3 μg/g, it’s greater than the content of selenium pakchoi root. The dry weight of pakchoi in selenium-wheat-straw(SW) treatment is similar with control, the content of pakchoi shoot is 0.4 ± 0.04 μg/g in SW treatment. The humic acid selenium in soil is increased when two kinds of selenium contained straw applied to soil, in which the proportion of FA-Se in soil total selenium is 3-4 times than the controltreated soil, and then the increasing of potential available Se content increased the effectiveness of soil Se and the selenium content of the pakchoi which is planted. The soil available selenium is accounted 21% in SP treatment, potential available selenium content accounted 44%, and SP treatment is more sutiable for the grown of selenium contained pakchoi than other treatments. Overall, the applied of selenium contained pakchoi stalks to selenium deficient area is sutiable. It not only increased the selenium content of the soil and plants, and the selenium content in plants is not caused by excessive selenium poisoning, but also increased the selenium potentially effective content in soil.2. During the culture of different selenium content soil, the transition is existed between ligand exchangeable selenium and fulvic acid selenium. In our experiment, water soluble selenium is the lowest soil selenium fraction compared with other selenium fractions. In acid soil, the more clay content, the more adsorption of soil selenium. In the cultivation process of 18 kindsofsoils,wefoundthatthetransformationbetweenfulvicacidsseleniumandligandexchangeableseleniumisexistedinallofthedifferentseleniumcontentsoilsamples.duringthesoilcultureofshandong,henan,hebeisoilwithdifferentseleniumcontentsoil,theconversionofseleniumformsinhighphshandongmoisturesoilisnotlimitedbysoilseleniumcontent,andthelowerphofhenan,hebeimoisturesoilseleniumfractiontransformationisnotactiveatthehighseleniumcontentsoil.accordingtothecomparisonofchongqingpurplesoilandbrownsoilinshenyang,foundthatthelessorganicmattercontentonselenium,thelowerinfluencefulvicacidseleniumandligandexchangeableseleniumtransformationwhenthesamesoilphexisted.differentseleniumtreatmentwithyunnanlatosolicredsoil,anhuiyellowbrownsoilandjiangsuwushansoil,thecontentoffa-seishigherthanha-secontent,theavailableseleniumcontentislowatthesametime.3.effectiveforcultivationofthedifferentseleniumcontentsoilofremovingtheavailablesoilseleniumshowedthatthetransformationoftheorganicseleniuminthesoilisabiochemicalreaction,whichrequiredtheparticipationofmicroorganisms.theavailableseleniumcontentishiger,whenthehigerphsoiliscultivated.thetranslationofotherformsofseleniumtoligandexchangeableseinfluencedbycalciumcarbonatecontentinsoil.indifferentsoils,addingcarbonandnitrogenaspromotethegrowthofmicrobialactivityfactor,didnotpromotethetransformationofsoilpotentialavailableseleniumtosoilavailableselenium,itmayberelatedtotheformationofdimethylseleniuminsoilandvolatility.addingcarbonandnitrogenaspromotethegrowthofmicrobialactivityfactor,intheformofsoilseleniumnotpromotetheuseofstateintheprocessoftransformationtotheavailableseleniumandpotentialavailablestatesofselenium.onthecultivationof18 kindsofdifferentseleniumcontentsoil,wefoundthatinallthesoilsamples,theconversionbetweenfulvicacidseandavailableseconversionisexist.