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通过对江苏省常熟市全市范围代表性水稻土采样并布置室内短期(20d)培育实验,研究土壤有机碳矿化过程动态,并分析其与微生物生物量碳和水溶性有机碳含量的关系。结果表明:研究区域水稻土有机碳含量变化为4.88～27.31g/kg,平均为18.07g/kg,全氮含量变化为0.58～2.84g/kg,平均为1.86g/kg;微生物生物量碳、氮及水溶性有机碳含量分别为294.0～1287.4,18.54～81.78和7.01～28.79mg/kg,且不同土属间存在显著差异(p<0.05);土壤呼吸强度为34.76～191.68mgCO2/(kg·d),平均为79.93mgCO2/(kg·d),不同土属间高低顺序为乌栅土>乌黄泥土>灰黄泥土>白土>黄泥土>乌沙土;培养期内有机碳日均矿化量为10.76～65.20mg-CO2/kg,平均为40.46mgCO2/kg,有机碳累计矿化量为215.25～1302.13mgCO2/kg,平均为807.20mgCO2/kg,不同土属间有机碳日均矿化量和累计矿化量变化趋势为乌栅土>乌黄泥土>乌沙土>白土>灰黄泥土>黄泥土;研究区域水稻土有机碳矿化率为3.07%～7.58%,但不同土属间差异不显著(p>0.05)。统计结果表明,土壤有机碳呼吸强度和日均矿化量与微生物生物量碳及水溶性有机碳之间均呈显著正线性关系,相关系数分别为0.686、0.594、0.826、0.749。
By sampling and arranging indoor short-term (20d) cultivation experiments on representative paddy soils in Changshu City, Jiangsu Province, the dynamic process of soil organic carbon mineralization was studied and its relationship with microbial biomass carbon and water-soluble organic carbon was analyzed. The results showed that the content of organic carbon in paddy soils varied from 4.88 to 27.31g / kg in the study area, with an average of 18.07g / kg and a total nitrogen content of 0.58 ~ 2.84g / kg with an average of 1.86g / kg. Microbial biomass carbon, The contents of nitrogen and water-soluble organic carbon were 294.0 ~ 1287.4, 18.54 ~ 81.78 and 7.01 ~ 28.79 mg / kg, respectively, and there were significant differences among different soil types (p <0.05). The soil respiration intensity was 34.76 ~ 191.68mgCO2 / (kg · d) with an average of 79.93mgCO2 / (kg · d). The order of the soil layers was Wuwei soil> Udon soil> gray-yellow soil> clay> yellow soil> The average mineralization amount of organic carbon was 215.25 ~ 1302.13mgCO2 / kg, with an average of 807.20mgCO2 / kg, and the average mineralization of organic carbon in different soil types was between 10.76 ~ 65.20mg-CO2 / kg with an average of 40.46mgCO2 / kg. And the cumulative mineralization trend of paddy soil> Wuhuang soil> Wusha soil> Clay soil> Wax soil> Huang clay soil. The organic carbon mineralization rate of paddy soil in the study area was 3.07% ~ 7.58% Not significant (p> 0.05). The statistical results show that soil organic carbon respiration intensity and daily average mineralization have a significant positive linear relationship with microbial biomass carbon and water-soluble organic carbon, the correlation coefficients are 0.686,0.594,0.826,0.749 respectively.