Changes In Labile Organic Carbon Under Different Management Types Of Bamboo Stands

Bamboo stands under intensive management(IM) and extensive management(EM) in Miaoshanwu Nature Reserve in Zhejiang were studied. Based on soil samples, chemical analysis and otherwise in intensively and extensively managed bamboo stands, the changes in lablie organic carbon(LOC) under different management types were researched, on other hand, dynamics of total organic carbon(TOC) and LOC with seasons were discussed. It provided a theoretical foundation for sustainable management and improvement of the soil fertility. The results were as follows:(1)Under IM, TOC were decreased by 7.01% and 18.90%, readily oxidized carbon (ROC) decreased by 31.22% and 46.03% and Water soluble organic carbon(WSOC) decreased by 11.89% and 11.50% in 0~10 and 10~20 cm soil layers, respectively. And light fraction organic matter (LFOM) was decreased 19.87% in the 0~20 cm soil layer.(2)Under the two types of management, SOC were decreased with increasing of soil depths, but both of the drop ranges were different. The vertical distribution of ROC under IM and EM paralleled that of TOC. The drop ranges of WSOC under the two types of management were showed fluctuation, and the WSOC content in an underlying soil layers were not much lower in surface layer. LFOM tended to accumulate in surface layer (0~20 cm).(3) There were not apparent differences between IM and EM in the percentage of WSOC to TOC. While after IM, the percentage of ROC to TOC and activity of carbon pool significantly dropped by 26.01% and 50.52%(p < 0.05) respectively in the 0~10 cm soil layer and dropped by 35.51% and 54.41% respectively in the 10~20 cm soil layer. Therefore, a mixture of organic and inorganic manures with the proper ratio should be applied to promote SOC and improve biological and chemical soil activity.(4)TOC, ROC, WSOC and LFOM were strongly correlated with soil nutrients(p < 0.01 or p < 0.05), but WSOC was not significantly related to available P. (5)The yearly dynamics of TOC, WSOC, and the percentage of WSOC to TOC under IM were the same as EM. But the yearly dynamics of ROC, the percentage of ROC to TOC and activity of C pool under two management types of bamboo stands were different, as follows:a: Dynamics of ROC under both IM and EM were decreased firstly, increased, and then decreased. Two peaks, which under EM in spring and summer, were measured in autumn and winter under IM.b: Dynamics of activity of C pool under two management types of bamboo stands were the same as the percentage of ROC to TOC. Activity of C pool under IM was decreased firstly and reached a minimum in winter, which was increased and reached a maximum in summer. That under EM was the same as ROC, which was at a maximum level in spring and reached a minimum in winter.In conclusion, IM causes TOC and various LOC to decline. Dynamics of various LOC under two management types of bamboo stands don't quite hang together.