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自养微生物在土壤中广泛存在,但原状土与非原状土对其CO2同化能力的影响尚不明确。因此,本研究采用14C连续标记示踪技术,选取亚热带区4种典型土壤进行室内模拟培养,探讨了原状土与非原状土对农田土壤自养微生物碳同化能力及其对土壤碳库活性组分的影响。结果表明:连续标记培养110 d后,原状土与非原状土样均表现出可观的CO2同化能力,根据估算,非原状土、原状土的CO2同化速率分别为0.015~0.148、0.007~0.050 g·m-2·d-1,说明土壤受扰动可能加剧自养微生物的活性,增强土壤自养微生物的CO2同化能力。相关分析表明,土壤自养微生物同化碳(14C-SOC)与其微生物截留碳(14CMBC)呈极显著正相关(R2=0.955)。而且,土壤可溶性有机碳(DOC)、微生物量碳(MBC)和土壤有机碳(SOC)的更新率分别为:0.9%~4.5%、2.2%~9.7%和0.09%~0.43%(原状土);0.26%~1.09%、3.6%~20%和2.9%~5.7%(非原状土)。土壤自养微生物同化碳的输入对土壤活性碳组分的DOC、MBC含量变化影响较大,而对SOC影响较小。本研究丰富和扩大了土壤微生物的基本功能和在土壤碳循环过程中作用的认识。
Autotrophic microbes are widespread in soils, but the effect of undisturbed and undisturbed soils on their CO2 assimilation is unclear. Therefore, in this study, 14C continuous marker tracing technique was used to select four typical soils in subtropical zone for indoor simulation culture. The assimilation ability of undisturbed soil and non-undisturbed soil on autotrophic soil carbon assimilation and its effect on active soil carbon pool Impact. The results showed that both the undisturbed soil and non-undisturbed soil showed considerable CO2 assimilation ability after 110 d continuous culture. Based on the estimation, the CO2 assimilation rates of undisturbed soil and undisturbed soil were 0.015-0.1448 and 0.007-0.050 g · m-2 · d-1, indicating that disturbed soil may aggravate the activity of autotrophic microorganisms and enhance the CO2 assimilation ability of soil autotrophic microbes. Correlation analysis showed that soil autotrophic carbon assimilation carbon (14C-SOC) had a significantly positive correlation (R2 = 0.955) with its microbial carbon retention (14CMBC). Moreover, the updated rates of soil dissolved organic carbon (DOC), microbial biomass carbon (MBC) and soil organic carbon (SOC) were 0.9% -4.5%, 2.2% -9.7% and 0.09% -0.43% ; 0.26% ~ 1.09%, 3.6% ~ 20% and 2.9% ~ 5.7% (non-undisturbed soil). Soil autotrophic microbial assimilation carbon input had significant effect on the contents of DOC and MBC in soil active carbon, but had little effect on SOC. This study enriches and expands the basic functions of soil microorganisms and their understanding of the role of soil carbon cycle.