Fire Effects Of Properties Of Wetland Soil In Sanjiang Plain

Long time study indicates that fire is a unique and important environmental factor of most ecosystems. Fire also plays an important role in both the preservation and evolution of wetland. However, studies on the effects of fires in wetlands are few compared with terrestrial habitats. Moreover, a disproportionate amount of research on wetland fires has focused on the recovery of flora and fauna relative to abiotic changes that can subsequently influence these processes. Wetlands are among the world's most productive environment, wetland research is very important in the research of global environment change because wetlands act as a "sink" of carbon and climate "stabilizer" on global scale. It's necessary the effects of fire on wetland ecosystem.Typically, fire alters the properties of wetland soil, although the nature of these alterations can be quite variable. However, studies on that are few. Fire effects on the typical wetland ecosystem in Sanjiang plain, Deyeuxia angustifolia wetland soil were studied in the paper. Base on the method of comparing sampling in burned site and unburned site , soil samples from three wetland soil lay ers(CK A, G) were taken.The results showed: burning can remove the litter accumulation on the soil surface. The soil bulk density and specific gravity increased and porosity of wetland soil reduced in O and A soil layers after fire. The pH value of the soil increased slightly the same year after fire, but no obvious changes the next year after fire. Fire can also reduce the content of organic matter (SOM) in the surface layer, and it's most obvious in the O and A soil layers at the same year after burning. One year after burning, the content of organic matter is still lower than unburned site. In addition, fire resulted in losses of total nitrogen (TN) total phosphorus(TP) and increases of totalpotassium(TK). The concentration of available nitrogen(N0) and available phosphorus(P0) decreased at the year after burning at Honghe NNR, but the ratio of No/TN-, Po/TP increased compared with unburned site. The concentration of available potassium(Ko) in the O soil layer increased obviously with the increase of ratio of Ko/TK, but that not found in mid-layer and deep-layer. One year after burning in the Ecological Experimental area, the ratio of No/TN in A and G soil layers was still higher than that in unburned site; but the ratio of Po/TP and Ko/TK were lower than those in unburned site. Fire can also increase the soil pH slightly. Meanwhile, It's obviously that fire affects the O and A soil layers, but slightly for the G soil layer.Fire influenced the density and storage of wetland soil organic carbon(SOC). The same year after fire the density of SOC decreased 37.2% compared with the unburned site; the next year after fire the density of SOC changed slightly compared with the unburned site. That proved that fire can change the process of carbon cycle of wetland soil and destroy its steady state. At the initial period after fire, the Deyeuxia angustifolia wetland soil behaved as the "fountain" of atmosphere CO2 and then as the "sink" of atmosphere CO2 some time later.The correlations analyses showed that there was a remarkable correlation between SOC and soil nutrient static soil pH and bulk density et al. in wetland.