黑碳添加对杉木人工林土壤微生物量碳氮的影响

向杉木人工林土壤中分别添加不同用量黑碳，以0％（C0）、1％（C1）和5％（C5）添加量（质量分数）作为不同处理，通过28d室内培养实验，研究了黑碳添加对土壤微生物量碳（ymc）和微生物量氮（MBN）的影响．结果表明，各处理土攘MBC含量变化趋势是前期急剧减少，后期增加，并趋于稳定；黑碳添加在一定程度上缓解了土壤MBN含量的减少，并随着黑碳添加量的增加，土壤MBN含量呈现增加的趋势．整个培养过程中，除第1d外，黑碳添加处理的土壤MBC和MBN含量始终高于对照处理，C5〉C1〉CO．同时，土壤可溶性碳（DOC）和可溶性氮（DON）含量也因黑碳的添加而呈现减少的趋势．

Effects of Black Carbon Application on Soil Microbial Biomass Carbon and Nitrogen in the Plantation of Cunninghamia Lanceolata

As a common soil component, black carbon （BC） plays an important role in forest carbon and nitrogen cycles. However, few studies on effects of BC application on soil microbial biomass car- bon （MBC） and nitrogen （MBN） in forest soils have been conducted. BC produced from the pyrolysis of branch and leaf litters of Cunninghamia lanceolata at 350 ℃ in capped muffle furnace for 2 h was incorporated into test soil at rates of 0% （CO）, 1% （C1） and 5% （C5） based on dried soil mass, and incubated for 28 days at 25 ℃. The results showed that the MBC decreased quickly under different treatments at the early stage of incubation, but increased steadily in later phase. The MBN increased gradually with incubation duration under the higher BC-amended treatments, but the pattern was signif- icantly different for the unamended soil, and tended to decrease throughout the experiment. Higher ap- plication levels provided further enhancement of MBC and MBN with the order as C5 〉 C1 〉 C0. In ad- dition, DOC and DON decreased with BC application and incubation duration.