砒砂岩与沙重构土体中有机碳的矿化特征

The Organic Carbon Mineralization Characteristics in Reconstructed Soil of Soft Rock and Sand

有机碳矿化过程可反映土壤CO2的释放强度,该文开展砒砂岩与沙复配土体的有机碳矿化研究,可为土体有机重构理论提供技术支撑和理论依据。该文在前期研究的基础上,主要选取砒砂岩与沙复配比分别为0∶1(CK)、1∶5(C1)、1∶2(C2)和1∶1(C3)的4个典型处理,采用碱液吸收法对土壤有机碳矿化过程进行分析。结果表明,C1、C2和C3处理间的有机碳含量无明显差异但均显著高于CK处理(P<0.05)。各处理的有机碳矿化速率在整个培养期内符合对数函数关系(P<0.01),可划分为1~11 d的快速下降阶段和11~30 d的稳步下降阶段。第11天的累积矿化量达到总矿化量的54.96%~74.44%。培养结束时,C1和C2处理的累积矿化量和潜在可矿化有机碳含量均显著高于CK处理低于C3处理,累积矿化率也以C1和C2处理最低。各处理土壤有机碳的周转速率常数较CK处理明显降低,滞留时间增加。综上,砒砂岩与沙体积比介于1∶5~1∶2之间时,可有效增加土壤有机碳的积累量,此时单位有机碳的矿化水平较低。

The organic carbon mineralization process can reflect the release intensity of soil CO2.Therefore,the study of organic carbon mineralization of soft rock and sand compound soil can provide technical support and theoretical basis for the theory of soil organic reconstruction.Based on the previous research,this paper mainly selected four typical treatments of 0∶1(CK),1∶5(C1),1∶2(C2)and 1∶1(C3),respectively,and analyzed the soil organic carbon mineralization process by lye absorption method.The results showed that there was no significant difference in organic carbon content between C1,C2 and C3 treatments,but they were significantly higher than CK treatment(P<0.05).The organic carbon mineralization rate of each treatment accords with a logarithmic function throughout the culture period(P<0.01),which can be divided into a rapid decline phase of 1~11 days and a steady decline phase of 11~30 days.The cumulative mineralization amount on the 11th day reached 54.96%~74.44% of the total mineralization amount.At the end of the culture,the cumulative mineralization and potential mineralizable organic carbon content of C1 and C2 treatments were significantly higher than those of CK treatment,and the cumulative mineralization rate was also the lowest with C1 and C2 treatment.The turnover rate constant of soil organic carbon in each treatment was significantly lower than that of CK treatment,and the residence time increased.In summary,when the volume ratio of soft rock and sand was between 1∶5 to 1∶2,the accumulation of soil organic carbon can be effectively increased.At this time,the mineralization level of unit organic carbon was lower.The research results have practical significance for the large area popularization of soft rock and sand compound technology.