不同二氧化碳浓度对玉米秸秆分解期间土壤微生物生物量碳的影响

通过室内模拟试验,研究了不同二氧化碳浓度对玉米秸秆分解期间土壤微生物生物量碳(SMBC)的响应。研究结果表明:土壤添加玉米秸秆后,激发了土壤微生物的生长,在培养第1 d各处理SMBC达到了整个培养期的最高峰后迅速下降,90 d以后SMBC的下降趋势趋于平缓。在不同浓度的二氧化碳培养条件下,0～15 d短期培养期间,各处理SMBC间差异不显著。30～270 d长期培养期间,SMBC随着二氧化碳浓度的升高而减少,各处理之间差异显著。通过相关性分析,各处理的SMBC分别与土壤有机碳、腐殖物质、富里酸、胡敏素间均呈显著正相关。二氧化碳浓度为0.03%的SMBC与土壤可溶性有机碳呈显著正相关(r=0.649,P<0.05),表明正常大气条件更有利于土壤微生物的活动。

Effect of Carbon Dioxide Concentration to Soil Microbial Biomass Carbon during Corn Stalk Decomposition

Response of soil microbial biomass carbon(SMBC) to different concentration of carbon dioxide was investigated during corn stalk decomposition by incubation experiment in laboratory.The results showed that the addition of corn stalk in soil stimulated the growth of soil microorganism.The SMBC in each treatment reached peak of whole incubation period on first day and then dropped rapidly.SMBC decreased slowly after 90d.Under the condition of different carbon dioxide incubation,the difference among different treatments was not notable during 0d to 15d incubation.SMBC decreased as the concentration of carbon dioxide increased and the differences were significant during 30d to 270d incubation.Soil organic carbon,humus,fulvic acid and humin were positively correlated with SMBC respectively.SMBC was positively correlated with water-soluble organic carbon(r=0.649,p<0.05) for carbon dioxide concentration of 0.03%,which indicated that normal atmosphere condition is more advantageous to the activity of soil microorganism.