| With the increasing of atmospheric CO2 concentration, carbon cycle has been one of the hot topics in the world in recent years. Soil carbon pool played a vital role of the global carbon cycle. Forest was an important gradient of the global carbon cycle and the biggest carbon pool of terrestrial ecosystem. On the one hand, forest could absorb and fix atmospheric CO2 and presented as carbon sink; On the other hand, with the felling and management of forestry measures it could make carbon which was fixed formerly released in various ways. It presented as carbon source. The influence of regeneration patterns changed on the soil respiration was significant. As a because of 50% at least of the 0～20 cm soil carbon in rapid cycle pool, CO2 annual fluxes of soil respiration were decuple higher of industry emission according to the ecosystem model. In this case, the study on 0～20 cm soil carbon was very important. It was estimated that 73% of global carbon pool was soil carbon in forest ecosystem. A narrow change of soil organic carbon could lead the significantly changes of atmospheric CO2, so as to effect the climatic change of global. Therefore, a deep research of different regeneration patterns in forest soil organic carbon and soil respiration was studied which would be critical important to estimate the changes of local and global carbon in the future.Chinese fir is a main commercial forest in the southern china, which plays an important role in adjusting rural industry structure and driving farmers to make a fortune. But, in the latest years, some unreasonable forest regeneration patterns had seriously affected climate structure of subtropical area. At present, the research of soil organic carbon of Chinese fir mostly concentrated on spatial scales, with dynamic study was less at home and abroad. Also, the relationship of soil organic carbon and soil respiration was not clear. Thus, background chosen in teaching forestry farm of Fujian nanping, which was nearly consistent. 70-year-old aged Chinese fir plantation which had stronger comparability, 17-year-old second-rotation Chinese fir plantation through artificial regeneration which was built on the partial overcutting forestland 17 years ago ( planting trees on the base of refining mountain after overcutting ) and 17-year-old Chinese fir and broadleaved mixed forest through natural regeneration by no planting (overcutting without refining mountain ) were chosen as research objects. This paper systematically researched dynamic changes and the differences of different regeneration patterns in soil organic carbon and soil respiration of Chinese fir Plantation. This paper hopes to provide scientific basis for perfecting theoretical system of sustainable management of Chinese fir Plantation. The major results were summarized as follows:(1) The monthly dynamic changes of soil light fraction organic matter contents of aged Chinese fir,artificial regenerated forest and natural regenerated forest were all significant. The maximum of soil light fraction organic matter contents appeared in January or March, and the minimum appeared in May,July and September. Their soil light fraction organic matter contents were among 8.47 g·kg-1～14.46 g·kg-1 and average contents presented as aged Chinese fir> natural regenerated forest> artificial regenerated forest. Compared with the aged Chinese fir, LFOM of artificial regenerated forest and natural regenerated forest respectively decreased 21.76% and 17.10% in a year, and both of them were significant to the aged Chinese fir (P<0.05), but there was no significant between each other (P>0.05).(2) The monthly dynamic changes of soil light fraction organic carbon contents of the three kinds of forest accord with regular rules. The maximum and the minimum of LFOC in aged Chinese fir respectively appeared in March and July, the other two kinds of forest respectively appeared in January,March and July,September. The annual average contents of LFOC contents of aged Chinese fir were both respectively improved 29.01% and 28.96%, compared with the artificial regenerated forest and natural regenerated forest. With the Cutting,burning and control burning in aged Chinese fir, the contents of soil light fraction organic carbon in artificial regenerated forest and natural regenerated forest were both decreased. The decline of soil light fraction organic carbon was obvious in artificial regenerated forest. Their LFOC showed significant differences with the aged Chinese fir (P<0.05), while LFOC contents of artificial regenerated forest and natural regenerated forest were not significant (P>0.05).(3) The changes of soil microbial biomass carbon contents in different kinds of forest had more consistent trend. MBC maintained in high level in January and March and began to decreased in May, reached the minimum in July, began to rally in September and reached the maximum in November. the maximum of MBC of aged Chinese fir,natural regenerated forest and artificial regenerated forest were all appeared in March, the minimum appeared in July and May.MBC contents showed significant differences (P<0.05) with the aged Chinese fir,natural regenerated forest and artificial regenerated forest, while aged Chinese fir and natural regenerated forest were not significant (P>0.05). The order of the average circulation of MBC showed as natural regenerated forest> aged Chinese fir> artificial regenerated forest. The average circulation of MBC of the natural regenerated forest was 1.51 and 1.56 more than that of the aged Chinese fir and the artificial regenerated forest.(4) The seasonal fluctuating pattern of soil dissolved organic carbon contents in different kinds of forest had inconsistent trend. The aged Chinese fir showed as January> March> November> September> May> July. The artificial regenerated forest and natural regenerated forest showed as November> March> September> January> July> May and January> March> November> September> July> May respectively. The average contents of DOC of natural regenerated forest were both improved respectively 11.25% and 47.90%, compared with the aged Chinese fir and artificial regenerated forest. There were significant differences with the aged Chinese fir and natural regenerated forest (P<0.05), while artificial regenerated forest and natural regenerated forest were not significant (P>0.05). There were significant differences with the aged Chinese fir and artificial regenerated forest.(5) The average rate of soil respiration in the three kinds of forest ranged from 1.66μmol·m-2·s-1～2.95μmol·m-2·s-1 in two years, which order presented as natural regenerated forest > aged Chinese fir> artificial regenerated forest. The average rate of soil respiration of natural regenerated forest and artificial regenerated forest were improved 28.38% and decreased 20.48% respectively, compared with the aged Chinese fir. There were significant differences (P<0.05) with the artificial regenerated forest and natural regenerated forest.(6) The changes of the litter respiration in three kinds of forest showed as consistent trend in two years, with higher level in summer and lower level in winner. The average rate of soil respiration of the natural regenerated forest was 1.34 and 2.19 more than that of the aged Chinese fir and the artificial regenerated forest. There were significant differences between the natural regenerated forest and artificial regenerated forest (P<0.05). While the significant differences between the aged Chinese fir and natural regenerated forest were not significant (P>0.05).(7) All the respiration rate of root-free soil in the three kinds of forest showed as single peak type in two years. They all maintained at higher level in plant growing-vigorous seasons and lower level in plant-dormant seasons. The maximum of the respiration rate of root-free soil appeared in June or July and the minimum appeared in January or December. The average rate respiration rate of root-free soil of aged Chinese fir,natural regenerated forest and artificial regenerated forest were respectively 0.97,0.54 and 0.68μmol·m-2·s-1.They all reached significant differences among each other (P<0.05), with the exceptional of different kinds of regenerated forests (P>0.05).(8) The changes of root respiration in the three kinds of forest showed as consistent trend in two years. They all maintain at higher level in the seasons of soil temperature,air temperature and rainfall were higher, with lower level on the contrast. The change ranges of root respiration of aged Chinese fir,natural regenerated forest and artificial regenerated forest were respectively 0.28～1.91μmol·m-2·s-1,0.16～4.28μmol·m-2·s-1 and 0.29～1.56μmol·m-2·s-1. There was significant difference among the aged Chinese fir, natural regenerated forest and artificial regenerated forest (P<0.05), but no significant difference between aged Chinese fir and artificial regenerated forest (P>0.05).(9) There were significant differences among each other of soil light organic carbon, soil microbial biomass carbon and soil dissolved organic carbon (P<0.05), but they were not significant difference with soil water(P>0.05), and showed negative correlation with soil temperature and soil respiration(P<0.05).
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