| Studying the contents and seasonal dynamics of soil organic carbon was an important method to reveal the turnover and regulation mechanism of the soil carbon pool. But Fire changes and influences organic matter content of the forest through direct combustion and heat denaturation methods.Through field sampling and lab analysis, we studied the dynamic variations, content differences, and correlations of total organic carbon (TOC) and organic carbon components in 0-15 cm deep soil in the Daxinganling Mountain areas that were burned under different fire intensities(organic carbon components included light fraction organic carbon (LFOC), heavy fraction organic carbon (HFOC), particulate organic carbon (POC), dissolved organic carbon (DOC), potential mineralization carbon (PMC) and microbial biomass carbon). The results showed in the unburned areas and low-intensity, moderate-intensity, and high-intensity burning area that pH means of soil were 5.49,5.35,5.42 and 5.69, NO3-N means were 6.45mg/kg,6.30mg/kg,7.31mg/kg and 7.40mg/kg, NH4+-N means were 20.61mg/kg,21.61mg/kg 23.45mg/kg and 24.39mg/kg, C/N means were41.81,23.04, 21.8,16.95, pH, N03-N, NH4+-N and C/N means increased with the enhancement of fire intensity.The results showed that in the unburned area and low-intensity, moderate-intensity, and high-intensity burning area,TOC contents of soil were 37.01-92.43 g/kg,40.13-91.45 g/kg, 27.89-83.55 g/kg, and 40.28-82.31 g/kg, LFOC contents were 1.42-22.57 g/kg,3.06-33.98 g/kg,2.31-19.77 g/kg, and 2.08-15.52 g/kg, HFOC contents were 35.09-54.59 g/kg,35.83-64.15 g/kg,23.83-55.11 g/kg and 34.09-51.11 g/kg, POC contents were13.88-47.95 g/kg, 14.9-61.19 g/kg,11.10-45.23 g/kg, and 14.21-42.55 g/kg, DOC contents were 286.08-513.25 mg/kg,252.47-567.38 mg/kg,278.63-520.13 mg/kg and 235.14-497.89 mg/kg, MBC contents were 88.88-1048.48mg/kg,80.42-869.05mg/kg,101.51-651.16mg/kg and 216.95-1072.38 mg/kg, soil total organic and carbon component contents showed a downward trend as fire intensity increases in the fire sample plot of different intensity, carbon component contents in the unburned areas was lower than in low-intensity.The contents of TOC, LFOC and DOC showed that 08-burning sample was higher than 02-burning sample. MBC contents showed that 08-burning sample was lower than 02-burning sample, but it was not significant difference. The contents of TOC, LFOC and DOC did not increase with the extension of recovery time after the fire.Soil TOC and HFOC did not varied significantly with the season (P>0.05). Soil LFOC, POC DOC and MBC varied significantly as "V" and double "V" with time (P<0.05).Between soil total organic carbon and carbon component, and carbon component and carbon component had different degree of linear correlation. |
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