Effect Of Iron-nitrogen Cycling Coupling System On The Activity Of Cadmium In Paddy Soil

Iron redox process is an important feature of paddy soil, ferric iron as an electron acceptor not only affect the form of nitrogen transformation in rice, but also affect its bioavailability. Iron oxide having a large specific surface area and strong chemical activity, is capable of adsorbing heavy metal cadmium, cadmium ion concentration changes in the soil, migration and transformation, bioavailability and environmental toxicity. In this study, paddy soil was studied by collecting different concentrations of cadmium contaminated paddy soil parameters were measured to analyze the interaction between the soil and the nitrogen cycle iron loop influence each other, iron and cadmium in circulation between the activities during rice growth the role of the nitrogen cycle activity and cadmium in between, thus inferred iron- Effect of cadmium on the activity of the nitrogen cycle, the rich paddy soil redox chemistry basic theory, to nitrogen use efficiency technology research foundation, but also to repair the cadmium contaminated paddy soils provide a theoretical basis. The main findings are as follows:(1) At different rice growth period, due to the soil conditions change so that the redox conditions change, then the soil nitrification- denitrification and is closely related to iron oxide redox reaction in which ammonium oxidation and Fe III related.(2) The process of growing rice, paddy soil soluble and exchangeable ferrous and exchangeable cadmium, cadmium reducible, oxidizable cadmium, cadmium residue significant correlation between soil iron morphogenic transition while cadmium activity impact.(3) Nitrite nitrogen in soil exchangeable Cd, cadmium reducible, oxidizable cadmium, cadmium residue was significantly correlated, paddy soil nitrogen cycle is the process of cadmium activity to some extent.(4) Paddy Soil iron- nitrogen cycle is closely coupled, and there may be a common effect of cadmium in soil activity.