Transformation Of Adding Selenium In Dark Brown Soil-vegetable System

This article primary studied, after add different content Na₂SeO₃ fertilizer in dark brown soil-vegetable system, the selenium's states and it's transformation in soil and vegetables. Also use the result to estimate the potential value of using this system to develop selenium-enrichment products.There are four kinds vegetable we used in study, they are houtui (Athyrium multidentatum Ching.), qumacai (Taraxacum mongolicum HandMazz), jinshuicai (Cruciferae Brassica subsp) , Pai-tsai(Cruciferae Brassica chinensis Linn) . we planted these vegetables in flowerpot , we plant houtui qumacai in open air according their living environment in the beginning of June and take samples after two months. While Pai-tsai and jinshuicai were planted in flowerpot with plastic covered like in greenhouse. They were planted at the end of August and get the samples after one mouth. The content of Na₂SeO₃ fertilized in houtui and qumacai is 0.545g/m² ( 3mg/kg ) , 0.909g/m² ( 5mg/kg ) , 2.727g/nr (15mg/kg) ; 0.125g/m² (Img/kg) , 0.4125g/m² (3.3mg/kg) -. 0.75g/m² (6mg/kg) in jingshuicai and Pai-tsai. we also made three blank samples to each system, besides these experiments, we made a test that to obsever selenium's states change in very dark brown soil within the period of two mounths . the content of Na₂SeO₃; we used in this test is Omg/kg, 3.3mg/kg, 6mg/kg and get samples at 1st, 2nd, 4th, 8th, 16th, 32th, 64th day after selenium has added. All samples use the HG- AFS method examin selenium content size.As a result, we discovered that the five states of selenium content in soil ( water dissolves selenium, exchangeable selenium, sour dissolves selenium, organic matter combined selenium, residual selenium) has a positive line relation with the content of fertilizer which add in soil except sour dissolves selenium. It is very stable and almost not influenced by the content of adding selenium. In the selenium of each state in soil, it's sour dissolve selinium that the content is lowest, don't exceed 10% of the total selenium quantity; water dissolves selenium the next in order; The content of the residual selenium is tallest, about 40-50% of the total selenium quantity; Two kinds of appearance seleniums of other are in each system the circumstance has the dissimilarity. The content of the avilable selenium has 30-40% that total selenium measure, at the same time we also discovered that dark brown soil is a kind soil with very srong ability in absorbing selinium. four vegetables in study , the rich ability of the houtui is most strong, containing the amount of selenium to the amount of selenium for the nature under the condition of the density of the outside source selenium for 15 mg/kg of 6400% or so. The rich selenium ability of the jingshuicai is also stronger, under the density of the 6 mg/kg of contain the amount of selenium to the amount of selenium for the nature of 1000% or so. And...