Regulation Of Soil Available Selenium And Crop Se-enrichment In Feng Cheng

Selenium is one of the essential elements for the normal growth of living things,if the human body is deficient in selenium,it is easy to cause the occurrence of Kashin-Beck disease and so on.Ingestion of se-rich agricultural products is the most direct and effective way to alleviate se deficiency in human body,and The enrichment effect of agricultural products on selenium in soil is affected by the bioavailability of selenium.It was found that the availability of selenium in soil was influenced by total selenium in soil.pH,organic matter and other factors,among which the effect of acidity and alkalinity is the most obvious.The effective selenium content in acidic soil is low,which affects the full utilization of selenium resources.Therefore,it is of great significance to improve the content of available selenium in soil to develop and produce se-rich agricultural products.In this paper,the distribution characteristics of total selenium and available selenium in the se-rich soil around Dongjiazhen Quannan village in Fengcheng were analyzed.Cattle manure,steel slag and biomass carbon,were applied to se-rich soil,and the pH,organic matter,CEC,available selenium and some heavy metals（Cd、Cr、Pb、Zn、Cu and Ni）in soil were tested at different time points in soil culture experiment.The effect and mechanism of three modifiers on the validity of soil selenium were discussed,and the effects of three modifiers on selenium uptake in leafy vegetables were studied by pot experiment in pakchoi（Brassica campestris L.）.The main conclusions of this study are as follows:1.The average soil selenium content in soil of Dongjia town Quannan village in Fengcheng was 0.55 mg.kg^-1.The available selenium content between14.6³4.5μg.kg^-1,And the average content is 24.7μg.kg^-1,accounting for 2.68%³.86%of total selenium.2.The results of soil experiment show that:（1）Cattle dung,Biomass carbon and Steel dregs can improve soil pH Value,and the soil pH value increased with the increase of modifier added;Cow manure and biomass charcoal have an significant on soil organic matter,while steel slag had no effect on soil organic matter.Among the three modifiers,only steel slag had the most obvious effect on the cation exchange capacity of soil.（2）Among the three modifiers applied,steel slag could significantly enhance the bioavailability of selenium in soil by the extent of increase.20.0%¹02.5%.while the effective selenium content of soil is inversely proportional to the amount of cow dung and biochar added.Between 8.4%and 25.2%.The results showed that steel slag was more suitable than cow dung and biomass carbon to regulate the bioavailability of selenium in se-rich soil in the study area.3.The results of pot experiment showed that the content of selenium in edible part of pakchoi decreased with the increase of the amount of cow manure and biomass carbon applied into the soil,which decreased by 0.5%⁴2.6%（cow dung）and 4.3%³0.3%.Between（biomass charcoal）;when steel slag was added to soil,the selenium content of edible part of Chinese cabbage was proportional to the amount of steel slag applied,and the increase of selenium content was higher than39.36%。The experimental results show that when the amount of steel slag is 0.5%and 1.5%,the soil pH is 5.82 and 7.88,respectively,and the optimum pH for most plants is between 5.0 and 7.0.Therefore,the actual amount of steel slag applied should be determined according to the growing environment of the vegetables.