Effects Of Restoration Methods Of Clear Cutting Land On Soil Organic Carbon Components In Broad-leaved Korean Pine Forest

In order to explore the dynamic effect on soil organic carbon fractions in vegetation-restored measures,bulk 0?20 cm depth soils collected from natural secondary forest and artificial forest regrowth after different restoration measures were subjected to total organic carbon,total nitrogen,hydrolysable nitrogen,soluble organic carbon,microbial biomass carbon,easily oxidized organic carbon,particulate organic carbon and light organic carbon were determined and analyzed.The results showed that different vegetation restoration measures were the main influencing factors of soil organic carbon content.In terms of natural restoration of vegetation,the soil total organic carbon content showed a trend of increasing with natural restoration of successional,but it was significantly lower than that of broadleaved Pinus koraiensis(p<0.05).And the total nitrogen in the soil could be approximately restored to the virgin Pinus koraiensis when the vegetation recovered to the Fraxinus mandshurica-Betula platyphylla and Fraxinus mandshurica-Phellodendron amurense forest.Though a highly significant correlation(p<0.05)between soil organic carbon and total organic carbon implied that the light-fraction organic carbon content raised with the increasing vegetation restoration though the light-fraction organic carbon content obviously lower than virgin Pinus koraiensis(p<0.05).The results suggested that light-fraction organic carbon can be considered as a sensitive indicator,which is quantitative description of the organic carbon variation caused by natural restoration of vegetation.In terms of artificial vegetation recovery,Compared with Corylus mciandshurica,the Fraxinus mandshurica plantation significantly increased the soil total organic carbon,total nitrogen,microbial biomass carbon,soluble organic carbon and particulate organic carbon,but obviously reduced the hydrolysable nitrogen(p<0.05).And the Betula platyphylla plantation significantly increased soil total nitrogen,microbial biomass carbon and soluble organic carbon,but significantly decreased total organic carbon,hydrolysable nitrogen and other total organic carbon component of content.The Pinus koraiensis plantation significantly increased soil total hydrolysable nitrogen,light-fraction organic carbon and for oxidized organic carbon sensitive to the effects of easily,but significantly decreased total organic carbon and total nitrogen of content.In addition to the Larix gmelinii plantation remarkably increased soil microbial biomass carbon and soluble organic carbon of content,but remarkably decreased total organic carbon and total nitrogen and hydrolysable nitrogen of content.Besides,the Picea koraiensis plantation obviously increased soil hydrolysable nitrogen and soluble organic carbon of content,but obviously reduced other organic carbon component of content.The results suggested that the artificially updated vegetation type has a significant effect on the content of soil organic carbon components.And the influence of Fraxinus mandshurica and Pinus koraiensis plantation on the components of organic carbon is obvious.From the timeliness of restoration of artificial vegetation of Pinus koraiensis,with the increasing years of artificial recovery,the total organic carbon,total nitrogen and hydrolyzed nitrogen contents of Pinus koraiensis plantations in different restoration periods represented an increasing trend.The difference of soil total nitrogen content between 62-years Pinus koraiensis plantation and virgin Pinus koraiensis was not significant.The total organic carbon content of 62-years Pinus koraiensis plantation in lower Soil layer was significantly higher than virgin broad-leaved Pinus koraiensis(p<0.05).These results indicated that the total organic carbon and total nitrogen in the soil could be approximately restored to the virgin Pinus koraiensis when the artificial vegetation recovered over 60 years.A highly significant correlation(p<0.01)between soil organic carbon and total organic carbon implied that the particulate organic carbon content raised with the increasing vegetation restoration years though the particulate organic carbon content in Pinus koraiensis plantation obviously lower than virgin Pinus koraiensis(p<0.05).The results suggested that particulate organic carbon can be considered as a sensitive indicator,which is quantitative description of the active organic carbon variation caused by vegetation-restored Pinus koraiensis plantations.