Chemical Morphology And Seasonal Variation Of Nitrogen In Different Types Of Wetlands In Liaohe Reservation Zone

Liaohe reservation zone,located in the southwest of northeast China,is the first reserve established for the purpose of protecting rivers in China.Liaohe reservation zone to this typical wetland as the research object,explores the Panjin coastal wetland,Qixing pond wetlandand Fudedian estuary wetland nitrogen in the form of chemical morphology characteristics,and on the basis of this season through indoor simulation experiment,environmental factors?temperature and moisture?research on the effects of nitrogen in wetland,and further deepen the experiment,the preliminary discussion on the biological carbon and nitrification inhibitor dicyandiamide?DCD?in the form of nitrogen in wetland.The research results show that:?1?In the vertical direction,the contents of organic matter,total nitrogen,organic nitrogen,ammonium nitrogen and nitrate nitrogen in the soil of Panjin coastal wetland and Qixing pond wetland show a trend of decreasing with the increase of soil depth.The total nitrogen content of wetland was mainly organic nitrogen,and inorganic nitrogen accounted for a small proportion,in which the nitrate nitrogen content was greater than the ammonium nitrogen content.The total nitrogen content F3<F2<F1,ammonium nitrogen content F3>F1>F2,nitrate nitrogen content F2>F1>F3 in soil of Fudedian wetland.Total nitrogen content in soil of the three types of wetlands was greater than100 mg·kg^-1,and the total nitrogen content in soil of 0¹0 cm on the surface of Panjin wetland was more than 1000 mg·kg^-1.?2?The ammonification rates of the three types of wetland soils first increased and then decreased with the increase of temperature.Temperature on soil nitrogen mineralization rate and the influence of the net nitrogen mineralization rate were extremely significant?P<0.01?,the temperature effect is shown as:10?<20?<30?.When the soil moisture content was 60%⁹0%,the influence of water on the ammonification,nitrification and nitrogen mineralization of the wetland soil was not significant?P>0.05?.The impacts of wetland types on soil nitrification rate,nitrogen mineralization amount and net nitrogen mineralization rate are as follows:Panjin coastal wetland>Fudedian estuary wetland>Qixing pond wetland.The results show that temperature increase will promote the mineralization process of nitrogen in different types of wetland soil in liaohe reservation zone.?3?Freeze-thaw cycle has a great influence on the changes of ammonium nitrogen and nitrate nitrogen contents in the topsoil of Panjin coastal wetland.After 15 freeze-thaw cycles,the content of ammonium nitrogen in the soil was higher than that in the control group.With the increase of freeze-thaw times,the content of ammonium nitrogen in the wetland soil under the treatment of 60%,70%and 80%moisture content first increased,then decreased and then increased,and the content of nitrate nitrogen first decreased,then increased and then decreased.?4?With the change of time,the content of ammonium nitrogen in the soil of wetland treated with different amounts of biochar increased first and then decreased.Biochar increased the content of ammonium nitrogen in soil to a large extent,but the change of nitrate nitrogen content was less.This suggests that biochar does not promote soil nitrification.?5?In the whole experiment,the ammonium nitrogen content in the treatment group with biochar and nitrification inhibitor was basically higher than that in the treatment group with biochar and nitrification inhibitor alone.At the end of the experiment,the nitrate nitrogen content in the treatment group treated with 2%biochar and nitrification inhibitor was higher than that in the treatment group treated with nitrification inhibitor alone.