Distribution Characteristics Of Nutrient Elements And Its Influencing Factors In The Wetland Soil Of The Sanjiang Plain,Northeast China

The Sanjiang Plain Wetland is the largest concentrated contiguous freshwater swamp wetland in China.It plays an important ecological service function in regulating floods,conserving water sources,regulating regional climate,and providing biological habitats.Nutrients in wetland soils have a crucial impact on the functioning of wetland ecosystems.In order to further understand the distribution characteristics of nutrients in wetland soils and the mechanisms and processes affecting the enrichment or migration of nutrients in soil,this thesis from the Honghe Nature Reserve?HHR?,The Sanjiang Nature Reserve?SJR?,the Naoli River-The Breqmites australis community,the Carex pseudocuraica community,and the urethane moss were collected from the Bielahong River Basin?NBB?,the Qixinghe-the Sanhuanpao Nature Reserve?QSR?and the Nongjiang River Basin?NJB?.A total of 29 soil samples were collected from the Cyperaceae community,Deyeuxia angustifolia community,island forest community,paddy field and dryland vegetation type soil samples.The content of nutrient elements in soil samples was analyzed and tested.The distribution characteristics?C,N,P,S,K,Ca,Na,Mg,Al,Cu,Zn,Fe,Mn,Co?in different regions and different vegetation types and their influencing factors.Through analysis of variance and correlation analysis of the data,it was found that the soil nutrients in the Sanjiang Plain wetland varied greatly from region to region.The non-metallic nutrient contents such as C,N,P and S in the Honghe Nature Reserve were higher,and the metal nutrient content was lower.The content of non-metallic nutrient elements in the Qixinghe-the Sanhuanpao Nature Reserve and the Nongjiang River Basin is relatively low,and the content of metal nutrient elements is high;except for Co and Zn elements,the nutrient elements in the Honghe Nature Reserve are generally low in content,the Qixing River-The content of the Sanhuanpao Nature Reserve and the Lijiang River Basin is relatively high.The contents of C,N,P and S in different regions showed a downward trend from the soil surface,and the highest content appeared in the range of 0-30cm.The content of Mn,Fe,Na,Mg,Al,K and Co is gradually increased from the surface of the soil,and the highest value is in the range of 40 to 60cm.The content of Co,Zn,Mn and Fe in soils of different vegetation types was significantly different,and the content in the soil of island forest was the highest.The content in the soil of Carex pseudocuraica-Cyperaceae was the second in the leaflet.The content of soil in the soil of Deeyeuxia angustifolia and Phragmites australis and Carex pseudocuraica is lower.Generally,the content of metal nutrient in the soil of island forest is higher than that of flooded or seasonal flooded wetland..Except for bryophytes,the contents of soil organic carbon,TN,P and S in different vegetation types decreased gradually from the surface layer to the vertical section,and the lowest values of organic carbon,TN,P and S appeared in 45-60cm.Within the scope.The content of nutrient elements in Fe,Mn,Na,Mg,Al,K,Co and other metals gradually increased from the surface layer,and the maximum content appeared in the range of 40 to 60cm.There were significant positive correlations between soil nutrient elements Na,Mg,Al,K,Ca and Fe in the Sanjiang Plain wetland;organic carbon,TN,NO₃^--N,NH₄⁺-N,P,S There was a significant negative correlation with soil pH;soil pH value was less correlated with the contents of elements such as Co,Cu,Zn and Mn.Studies have shown that wetland soil moisture is one of the important factors affecting the nutrient content of wetland soil.Wetland reclamation has extremely important influence on the content and distribution of metal nutrient elements in wetland soil of the Sanjiang Plain.After the wetland reclamation,the content of metal nutrients in the soil increased,and the content of non-metallic nutrients such as organic matter decreased.Studies on the factors affecting the distribution of nutrient elements in the Sanjiang Plain wetland show that soil parent material,microbial,pH,texture,structure,hydrological status,soil redox potential,soil vegetation type,hydrothermal status and industrial and agricultural production and other human activities Synergistically interacts with the distribution of nutrients in wetland soils.At present,the distribution characteristics of nutrients in the Sanjiang Plain wetland are mainly affected by soil moisture and reclamation activities.The establishment of protected areas has a positive impact on maintaining high nutrient levels in the soil.