The Seasonal Dynamics Of Soil Microbial Biomass Of Larix Gmelinii Forest After Wildfire

Nowadays, the global warming is an indisputable fact. With the global carbon circulation problems become remarkable, Soil microbial biomass carbon especially the forest soil microbial biomass carbon increasingly attracted people’s attention. We researched the soils burned by high-intensity wildfires in different years after the fire (2002and2008) and the soils unburned in the Larix gmelinii, colleced soils samples per month from may to October (2010). Used a fumigation-extraction method (FE) to examine seasonal dynamics of soil microbial biomass carbon (Cmic) and soil microbial biomass nitrogen (Nmic) of the soils burned in different years, at the same time, we compared the relationship between Cmic、Nmic and the other soils factors. The results showed that:there was a significant difference between Cmic and Nmic of the soils burned in different years (p<0.01), the amount of Cmic and Nmic of the burned soils is less than the unburned and the decrement is increase with the ages of the burn time. The Cmic in the Larix gmelinii soils burned in2002varied from61.03-427.26mg·kg-1and in the unburned sample area it varied from70.02-1065.38mg·kg-1; the Cmic in the Larix gmelinii burned in2008varied from199.32-704.85mg·kg-1and in the unburned sample area it varied from76.36-781.92mg·kg-1, the Nmic in the Larix gmelinii burned in2002varied from6.24-67.03mg·kg-1and in the unburned sample area it varied from15.63-75.18mg·kg-1; the Nmic in the Larix gmelinii burned in2008varied from26.20-73.70mg·kg-1and in the unburned sample area it varied from24.25-105.01mg·kg-1. The seasonal dynamics of soil microbial biomass、nitrogen within all the sample plots performed samely:appear significant fluctuation from the peak in the early spring when the soil was thawing, then, it had little fluctuation with the time in the growing season, rised after the growing season and appeared a peak in autumn then dropped. The Cmic and Nmic were positively correlated with soil water content. The Cmic and Nmic was negatively correlated with soil temperature. The Cmic and Nmic were not significantly correlated with the ammonium and nitrate forms. The Cmic and Nmic were not significantly correlated with the pH value.