Study On Dynamic Changes Of Plant Biomass And Soil Microbial Biomass During Degradation Process Of The Gansu Gahai Wetland

Wetland ecosystem is located between aquatic and terrestrial ecosystems,with unique hydrology,vegetation and soil characteristics.Plant biomass is the core part of the wetland ecosystem plant library,soil microbial biomass is an important part of the soil in the wetland ecosystem library,both to promote between vegetation and soil material circulation and energy flow is extremely important.The research chose swamp meadow and peat wetland of Gahai as the study subject and analyzed the changes of plant biomass and soil microbial biomass during the degradation process by using the principle of restoration ecology and method of combining field survey with laboratory analysis.The conclusions were as follows:(1)As the degree of degradation,the plant biomass content is less,the performance is:the swamp meadow non-degradation>mild degradation>moderate degradation;peat wetland non-degradation>degradation.As the research time,July appeared maximum aboveground biomass,swamp meadow next August and September,May and June is lesser,peat wetland next August and June,September and May smaller;Maximum belowground biomass in June,swamp meadows next in May and September,in July and August is lesser,peat wetland next July and September,May and August smaller.From the perspective of total biomass proportion,swamp meadows,July,August the content of aboveground biomass is greater than the belowground biomass,May,June and September aboveground biomass and belowground biomass content relative equilibrium;Peat wetland September belowground biomass content is bigger,July and August aboveground biomass content is bigger,May aboveground biomass and belowground biomass content is relatively balanced.Degradation of wetland plant biomass content gradually reduce,reduce the plant productivity significantly.(2)During degradation process of the wetland,the plant biomass,plant organic carbon,total N,total P,total K nutrient content is reduced.From the point of time,the aboveground biomass organic carbon content in July and August the largest,May smaller;belowground biomass organic carbon content in September the largest,July smaller.Total N content of aboveground biomass range between 0.83% and 2.19%,the largest in July and August,May smaller;Total N content of belowground biomass range between 0.71% and 1.91%,the largest in June,July smaller.Total P content of aboveground biomass range between 0.13% and 0.32%,the largest in July and August,May smaller;Total P content of belowground biomass range between 0.10%and 0.21%,the largest in June,July smaller.Total K content of aboveground biomass range between 0.82% and 1.86%,total K content of belowrground biomass range between 0.62% and 1.77%,total K content in volatility changes in time.(3)As the degree of degradation,soil microbial biomass C and N decreased gradually.Soil microbial biomass C and N decreased with the increasing of soil depth.The monthly average content of soil microbial biomass C and N in Gahai wetland with the seasons change law showed an "up-down" trend.The overall trend of soil microbial biomass C showed:non-degradation(685.12mg/kg)>mild degradation( 592.60mg/kg) >moderate degeneration( 509.61mg/kg) >severe degeneration( 425.71mg/kg).The overall trend of soil microbial biomass N showed:non-degradation(128.68/kg)>mild degradation(108.70/kg)>moderate degeneration(94.00/kg)>severe degeneration(77.29/kg).The differences of soil microbial biomass C and N of 0-40 cm among non-degradation,mild degradation,moderate degeneration and severe degeneration were significant(P<0.05).The total content of soil microbial biomass C and N showed:0-10cm>10-20cm>20-40 cm.Soil microbial biomass C of10-20 cm and 20-40 cm are 79.11% and 59.47% of 0-10 cm,Soil microbial biomass N of10-20 cm and 20-40 cm are 77.14% and 56.50% of 0-10 cm.The differences of soil microbial biomass C and N among 0-10 cm,10-20 cm and 20-40 cm in months of the years were significant( P<0.05).The monthly average content of soil microbial biomass C and N in Gahai wetland with the seasons change law is shown as:the highest in July,June and August second and the lowest in September and May.(4)As the degree of degradation,the study area the aboveground biomass C/N ratio and belowground biomass C/N ratio showed a trend of increase.Correlation analysis showed that the aboveground biomass and the belowground biomass of organic carbon,total N,total P content were positively significant correlation and correlation is bigger,the aboveground biomass organic carbon content and total N,total P content and the content of total N and total P content were positively significant correlation and correlation is bigger,the aboveground biomass total K content of nutrient and aboveground biomass were positively significant correlation,but the correlation is smaller.The aboveground biomass with its nutrient and the belowground biomass with its nutrient were similar.Positively correlated relationship between soil microbial biomass carbon,nitrogen and correlation.Soil microbial biomass and plantaboveground biomass were positively correlated with and correlation is larger,and plant belowground biomass were positively correlated relationship but correlation is smaller.