Study On Physical And Moisture Properties Of Soil In Gahai Wetland

The moisture-physical properties of the wetland soil is an indispensable indicatorto reflect wetland water conservation, soil and water conservation features. Therefore,to study soil moisture-physical properties play an important role for in-depthunderstanding of wetland ecosystem functions. Gansu Gahai wetland is one of thetypical cold plateau wetland in island,and it’s important for water conservation andecological protection to Yellow River. The types of wetlands including Peat-wetland,Swmap, Mountain-wetland and Flood-wetland. Study on the soil moisture-physicalproperties in different types of wetlands, can provide a scientific basis for ecologicalconstruction and environmental protection in Gahai. In this study, using acombination method of field investigation and laboratory analysis. Study on the soilphysical properties and water retention, water storage capacity in deffrent wetland,The main research results as following:(1)Soil particle composition showed similar distribution law in4wetland types.The most abundant are fine sand (0.05~0.25mm) in Peat wetlands and then arecoarse sand (0.25~1mm). and the highest content in Swmap, Nountain-wetland andFlood-wetland are fine sand (0.05~0.25mm). Soil particles composition are differentin different wetland.The average percentage of fine sand in soil are performance asSwmap(62.60%)>Flood-wetlands(58.04%)>Mountain-wetland(53.89%)>Peatwetland(38.49%), The average percentage of crude sand in soil are performance as Peatwetland(57.31%)>Mountain-wetland(41.40%)>Swmap(34.80%)>Flood-wetland(21.54%).(2) The soil bulk density of four wetland types increased with the increment ofsoil depth. In the layer of0-80cm, the soil bulk density of Peatwetland, Swmap、Mountains wetland and Flooding wetland was0.89g/cm3,1.17g/cm3,1.11g/cm3,1.18g/cm3. The reason is the high organic content in surface soil, soil are more loose,withthe soil depth increasing, soil organic matter content decreases, the soil graduallybecome more compact and the soil bulk density increased.(3) In different soil layers,with the increasing depth,soil capillary porosity,non-capillary porosity and total porosity are decreased.In different types of wetlands,In the layer of0-80cm,the capillary porosity average in Peat wetland, Swmap,Mountains wetland and Flooding wetland are38.54%,26.66%,22.39%and26.23%，andthe non-capillary porosity average in Peatwetland,Swmap,Mountains wetland andFlooding wetland are82.24%,68.05%,60.12%and53.90%. The results show that the soil porosity are more large in Gahai wetlands, the ability to maintain moisture aremore strength. Among them, peat wetland have the lagerest porosity.(4) In different soil layers,with the increasing depth,soil ratio of porosity aredecreased.In different types of wetlands, In the layer of0-80cm,the soil ratio ofporosity average in Peat wetland, Swmap, Mountains wetland and Flooding wetlandare2.36,0.91,0.68and0.66. The results showed that the peat wetland soil aeration,water permeability and water holding capacity are more coordination, and able tomeet the demand of the vegetation on air and water,is good to the roots stretch andactivities.(5) The average soil moisture in4wetland types are225.13%(Peat wetland),159.46%(Swmap),79.47%(Mountains wetland) and111.78%(Flooding wetland),Soilmoisture is higher than soil itself, indicating Gahai wetland soil water storage andhydropower holding are more strong, can be effectively regulated surface runoff andwater conservation.(6)In different soil layers,with the increasing depth,soil capillary water andsaturated water are decreased.In different types of wetlands, in the layer of0～80cm,the soil capillary water average in Peat wetland, Swmap, Mountains wetland andFlooding wetland are249.68%,177.87%,100.31%and154.34%、and the saturatedwater average in Peatwetland,Swmap,Mountains wetland and Flooding wetland are282.92%,181.35%,125.11%and208.23%. The results show that on Gahai wetlandsoil permeability, aeration and water holding capacity of more coordinated, and havebetter water conservation function.(7) In different soil layers,with the increasing of depth,capillary water storagecapacity and saturated water storage capacity are decreased.In different types ofwetlands, in the layer of0-80cm,the capillary water storage capacity average in Peatwetland, Swmap, Mountains wetland and Flooding wetland are249.68%,177.87%,100.31%and154.34%, and the saturated water storage capacityaverage in Peatwetland,Swmap,Mountains wetland and Flooding wetland are282.92%,181.35%,125.11%and208.23%. The results show that on Gahai wetlandsoil permeability, aeration and water holding capacity of more coordinated, and havebetter water conservation function.(8) In different soil layers,with the increasing of depth, the water storagecapacity are decreased. In the layer of0-80cm,the soil water storage capacityaverage in Peat wetland, Swmap, Mountains wetland and Flooding wetland are 275.42t/hm2,203.53t/hm2,177.04t/hm2and124.74t/hm2.(9) Soil factor correlation analysis in Gahai wetland showed that total soilporosity, moisture content, saturated water and saturated water storage capacity arenegatively correlated with the soil bulk density.Soil moisture content, saturated waterand saturated water storage capacity was positively correlated with the total soilporosity. Saturated water and saturated water storage capacity was positivelycorrelated with soil moisture content. between saturated water and saturated waterstorage capacity was positive correlation.