生物炭对杨树人工林土壤微生物量及碳源代谢多样性的影响

生物炭不仅可以改良土壤理化性质,并且能够帮助土壤长期固碳从而减缓温室气体的排放。以江苏东台杨树人工林土壤为对象,设计4种生物炭添加量CK(0)、T1(40 t/hm²)、T2(80 t/hm²)、T3(120 t/hm²),探究生物炭及其季节动态变化对土壤理化性质、微生物量和碳源代谢的影响。结果表明:生物炭施入降低土壤含水率,却使得土壤pH升高; 生物炭导致土壤微生物量氮(SMBN)下降,并且SMBN具有明显季节动态变化,即冬春偏高、夏秋相对较低; 而生物炭没有明显改变土壤微生物量碳(SMBC),但SMBC季节动态变化明显。高浓度生物炭(T3)显著提高了微生物在Biolog平板上的AWCD(平均单孔颜色变化率),但对碳源代谢多样性影响不显著。主成分分析表明,相比不同的施炭处理,同一处理季节的差异更显著地影响了微生物碳源的代谢模式。

Effect of biochar on soil microbial biomass and the diversity of carbon source metabolism in poplar plantation

Biochar is evaluated as a means to improve soil physicochemical properties and to mitigate climate change, which has received widespread attention. This study targeted on poplar plantation in Dongtai in Jiangsu Province and designed four different levels of biochar: CK(0), T1(40 t/hm²), T2(80 t/hm²)and T3(120 t/hm²)to investigate how biochar and seasonal changes affect soil physicochemical parameters, microbial biomass and metabolic activity of carbon sources. The result showed as follow: soil moisture content decreased after the addition of biochar, while soil pH significantly increased. Biochar caused the decrease of SMBN(soil microbial biomass nitrogen), and its values presented significant seasonal changes: the values in winter and spring were higher than that in summer and autumn; whereas biochar did not change the seasonal SMBC(soil microbial biomass carbon)in this study but it presented the significant seasonal changes. High level of biochar(T3)improved the AWCD(average well color change)value of microbes on Eco-plate, but exerted no effect on diversity of carbon source metabolism. However, compared with the effects of biochar, seasonal changes exerted more dramatic effect on microbial metabolic patterns.