Selenium Availability And Its Regulation In Acidic Selenium-rich Soil

In this study,we have analyzed 30 Se-rich soil samples collected from the surface layer(0-20 cm)in Fengcheng Ecological Selenium Valley,a series of experiments were carried out to investigate the impacts of some factors on the availability of selenium.The experiments aimed to do more systematic and further research about the availability of selenium in the Se-rich soils of Fengcheng Ecological Selenium Valley.To be exact,what we did includes the following aspects,e.g.heavy metals,the total selenium in soil,land uses,and the physical and chemical properties of soil.The successful invistigation of the said experiment proves that the factors have different influence on the the availability of soil selenium.The results show that the total content of soil selenium(541-831 ?g/kg)in the region reaches the Se-rich soil national standard and the soil environment quality is in a state of health in general.The water-soluble and exchangeable selenium with high bioavailability are of low content ranging froml0.30-38.23 ?g/kg and 10.68-38.45?g/kg,respectively.These two fractionations of selenium are distinct from each soil sample.Moreover,they have significant correlation with the total selenium.The total selenium in soil,different land uses and the physical and chemical properties of soil have impacts on the availability of soil selenium.Activation coefficient of selenium in paddy is higher than that in dry land.The total phosphorus and available phosphorus have significant positive correlation with the water-soluble selenium.Under the certain condition for the effectiveness of selenium,the soil which has higher total selenium content can provide more available selenium to the crop.Therefore,our research results can be said to make a great sense in the study of the availability of selenium and provides a theoretical basis for exploiting the selenium-rich soil resources in Fengcheng Ecological Selenium Valley.And,to some extent,it is also helpful to promote the self-protection ofhuman health.A series of field experiments were carried out to investigate the effects of 5 different rectification measures on the quality of highly acidic Se-rich soil.And for reaching this goal,phosphate fertilizers were applied in the above mentioned experiments.To be exact,including the following rectification measures,that is,applying composite bio-organic manure and the chemical fertilizers with calcium magnesium phosphate which in two dosages.The results shows that the application of different kinds and dosages of phosphoric fertilizers can all help to improve the content concentration of the available selenium.The above mentioned high-volume treatments,including the high volume application of calcium magnesium phosphate,calcium magnesium phosphate mixed with bio-organic fertilizer worked most effectively,the improvements of content of soil available selenium were 42.16?g/kg and 43.54?g/kg respectively,content of organic selenium in grains were 28.65ug/kg and 39.27ug/kg correspondingly.In addition,the privileged enhancement brought about by using the said 5 kinds of treatments helps to promote the experimental results to a very significant level(p<0.01).Finally,pepper field trial showed that the 6 kinds of calcium magnesium phosphate and natural active silicon fertilizers treatments made the content of soil available Se is improved in different degrees.Among them P,P1,P+Si and P1+Si treatments was increased in significantly level(p<0.01)to soil selenium availability compared to CK(44.77 g/kg),from low to high were P,P+Si,P1,P1+Si.All treatments were made to pepper reachedthe standard of Se-rich,the Pepper Fruit Se content of P1,P+Si andPl+Si treatments is 38.73 g/kg,30.26 g/kg and 42.92 g/kg,Comparing CK,it is increased 21.07 g/kg,12.60 g/kg and 25.26 g/kg respectively and reached a significant level(p<0.01).The increasing application of calcium magnesium phosphate endogenous control technology has a good effect in the aspect of selenium rich agricultural products.Different treatments increase between the 0.79%-81.03%on pepper yield.The P +Si treatment has the biggest increase degree and the growth rate reached 81.03%,but P1+Si and P1 treatment only increase 26.88%and 23.32%on pepper yield,less than P+Si and P treatment.It is showed that the calcium magnesium phosphate fertilizer on pepper yield and economic benefit raising have a most suitable quantity and economic perspective is feasible.