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研究岩溶区土壤有机碳与微生物区系数量和土壤酶活性之间的关系有助于认识有机碳的积累机制。以丫吉岩溶试验场这一典型岩溶生态系统的洼地、坡地与垭口三种岩溶形态为研究样点,分别采集0～10、10～20 cm与20～30 cm土壤样本,采用浓硫酸-重铬酸钾外加热法测定土壤有机碳质量分数,用平板菌落计数法获取微生物区系数量,采用比色法分析土壤酶活性。结果表明,随着土壤剖面深度加深,土壤有机碳质量分数显著下降,在0～10 cm,洼地的土壤有机碳质量分数为40.10 g·kg-1,显著高于垭口的38.28 g·kg-1和坡地的24.42 g·kg-1;洼地土壤剖面从上至下细菌数量分别为3.26×106、2.73×106CFU·g-1和1.15×106CFU·g-1,均显著高于垭口和坡地;洼地土壤0～10 cm的脲酶活性为1.92 mg·(g·24 h)-1,显著高于垭口和坡地的1.12 mg·(g·24 h)-1和0.77 mg·(g·24 h)-1;碱性磷酸酶活性在洼地土壤剖面均显著高于垭口和洼地剖面。统计分析显示,不同类型的微生物数量和土壤酶活性与有机碳之间的关系在剖面上的表现并不一致,细菌数量、脲酶活性、归一化的微生物数量和归一化的土壤酶活性与土壤有机碳质量分数均呈显著正相关。以上研究结果表明,岩溶生态系统土壤有机碳积累下,土壤细菌数量、总微生物数量与总土壤酶活性相应提高。细菌数量、归一化的微生物数量与归一化的酶活性可以作为岩溶区土壤有机碳质量分数的指示指标。
Studying the relationship between soil organic carbon and the number of microflora and soil enzyme activity in karst area is helpful to understand the mechanism of organic carbon accumulation. Taking the three karst forms of depression, slope and pass in the typical karst ecosystem of the Yaji karst test site as the sample sites, soil samples of 0 ~ 10, 10 ~ 20 cm and 20 ~ 30 cm were collected, respectively. Chromic potassium external heating method was used to determine the mass fraction of soil organic carbon. Microbial flora was obtained by plate colony counting method. Soil enzyme activity was analyzed by colorimetric method. The results showed that with the deepening of soil profile depth, the mass fraction of soil organic carbon decreased significantly. At 0-10 cm, the mass fraction of soil organic carbon in depression was 40.10 g · kg-1, which was significantly higher than that of Passou 38.28 g · kg-1 And 24.42 g · kg-1 on the sloping land. The top-bottom bacterial numbers of the soil profile in the depression were 3.26 × 106, 2.73 × 106CFU · g-1 and 1.15 × 106CFU · g-1, respectively, The soil urease activity at 0 ~ 10 cm was 1.92 mg · (g · 24 h) -1, which was significantly higher than that of 1.12 mg · (g · 24 h) -1 and 0.77 mg · (g · 24 h) 1; alkaline phosphatase activity in the depression of the soil profile were significantly higher than Pass and depression profile. Statistical analysis showed that the relationship between the amount of different types of microorganisms and soil enzyme activity and organic carbon in the cross section of the performance is not consistent, the number of bacteria, urease activity, the number of normalized microorganisms and normalized soil enzyme activity and soil Organic carbon mass fraction showed a significant positive correlation. The above results show that under the accumulation of soil organic carbon in karst ecosystem, the amount of soil bacteria, the total number of microbes and the total soil enzyme activity increased accordingly. The number of bacteria, the number of normalized microorganisms and the normalized enzyme activity can be used as indicators of soil organic carbon mass fraction in the karst area.