黑碳添加对土壤活性有机碳和原有机碳的影响

Effects of Black Carbon Addition on Soil Labile Organic Carbon and Native Soil Organic Carbon

通过室内培养实验,向土壤(甘蔗土)中分别添加不同用量的黑碳(BC,350℃热解水稻秸秆),添加量分别为0(BC0)、1%(BC1)、2%(BC2)、3%(BC3)、4%(BC4)和5%(BC5),研究黑碳添加量对土壤活性有机碳和原有机碳的影响。结果表明,在25℃培养条件下,土壤易矿化碳(Cm)随黑碳添加量的增加而增加;土壤微生物生物量碳含量亦随添加量的增加呈增加趋势(BC3处理除外)。土壤可溶性有机碳含量在BC1、BC2和BC3处理之间的差异不显著,并显著低于对照土壤(BC0);应用δ13C自然丰度方法研究发现,BC1处理抑制了土壤原有机碳分解,而BC2、BC3、BC4和BC5处理促进了土壤原有机碳的分解,但统计上未达显著水平。

Black carbon （BC） is an important pool of the global C cycle. However, very little is known about the effect of BC addition on soil labile organic carbon and native soil organic carbon. In the study, BC was produced by charring the rice straw under 350℃ and mixed with soil under different rates of addition levels （0, 1%, 2%, 3%, 4%, 5%）, and incubated for 56 days at 25 ℃. The results indicated that soil easily mineralization carbon （Cm） increased with the increase of BC addition level, and soil microbial biomass carbon （MBC） content had the similar trend （exception for 3%）. Dissolved organic carbon （DOC） content in soil showed no significant difference among the lower addition levels （1%, 2%, 3%）, but it was obviously lower in BC amended soils （1%, 2%, 3%） relative to the unamended soils. Using natural 13C abundance method, the results suggested that BC addition inhibited the native SOC decomposition at rate of 1% BC addition, but stimulated the native SOC decomposition at rates of 2%, 3%, 4% and 5% BC addition. However, the effects of BC additions on the native SOC decomposition were not significant among different treatments.