Study On Selenium Form And Valence Distribution And Bio-selenium Enrichment Ability In Selenium-enriched Soil

In this study,the selenium-rich soil in the eastern part of Qinghai was used to study the selenium form and valence and transformation in the soil under high altitude conditions.At the same time,the selenium enrichment ability of five crops and the selenium form in the grain?bulb?were studied.The distribution characteristics provide a theoretical basis for the rational utilization of selenium-rich soil resources in eastern Qinghai and the development of selenium-rich agricultural products bases.In the research area,25% of the farmland surface soil in Ledu District belongs to the selenium-soil soil,and the surface soil of the farmland in Ping'an District belongs to the selenium-rich soil.The form of selenium in the tested soil was mainly organically bound,accounting for 36.55% of the total selenium content in the soil.The dissolved selenium,exchangeable and carbonate-bound selenium and residual selenium accounted for 10.84% to 21.35%,11.53% to 23.41%,and 11.69% to 23.98%,respectively.The content accounts for 3.52% 11.81% of the total selenium content.Se⁴⁺ and Se⁶⁺ exist in soluble selenium and exchangeable and carbonate-bound selenium,and Se^2-is absent,and Se⁶⁺ is the main form.Selenium in the grains of the five crops is mainly present in organic selenium.The percentage of organic selenium in rapeseed was the highest,which was 84.55%.The percentage of organic selenium in broad bean was the lowest,which was 68.41%.The selenium enrichment ability of five crops was: garlic>rapeseed>oats>wheat> broad beans.The transfer coefficient?TF?of garlic was bulb> above;the transfer coefficient?TF?of broad bean,oat and rape was above > grain;the transfer coefficient of wheat?TF?)is grain > above.The soluble state selenium content and crop grains?bulbs?selenium achieves very significant positive correlation?p<0.01?.Is quadrivalence selenium and are hexavalent selenium content in the grains and crops?bulb?was positively related to relationship.There was no correlation between the negative divalent selenium content and the selenium content of the six crop grains?bulbs?.The contents of soluble selenium and exchangeable and carbonate-bound selenium in soil increased with the culture time and temperature increased.The contents of Se⁴⁺ and Se⁶⁺ in soluble selenium and exchangeable and carbonate-bound selenium increased with the increase of incubation time and temperature.