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为明确外源有机物质和无机碳酸盐对桂西北石灰土土壤有机碳矿化的影响,加深对土壤有机碳周转特征的认识,本文以广西环江县喀斯特地区的棕色石灰土、黑色石灰土和地带性红壤(对照)为研究对象,进行为期100d的室内培养试验[对照(无外源物添加,CK)、添加14C-稻草(S)、添加Ca14CO3(C)],并对土壤呼吸释放的CO2及14C-CO2含量进行测定。结果表明:培养100d后,外源物的添加均明显促进了红壤、棕色和黑色石灰土有机碳的矿化,外源14C-稻草和Ca14CO3对上述土壤有机碳矿化的激发效应分别为28.7%、46.2%、15.5%和127.0%、175.3%、100.1%;土壤表观累积矿化量中外源Ca14CO3的贡献率分别为40.4%、48.4%、19.6%;土壤类型和添加物及两者间的交互作用均对土壤有机碳矿化的激发效应、土壤表观累积矿化量中外源物的贡献、土壤有机碳的矿化速率、土壤有机碳累积矿化量/率有显著影响。因此,外源有机物质和碳酸钙的添加改变了土壤有机碳的矿化特征,对于含碳酸盐的石灰土,研究土壤有机碳矿化、周转规律,评估其对大气CO2的影响必须考虑无机碳酸盐的贡献。
In order to clarify the effect of exogenous organic materials and inorganic carbonates on the mineralization of soil organic carbon in the northwestern Guangxi Province and deepen the understanding of the characteristics of soil organic carbon turnover, this paper takes the brown limestone soil, the black lime soil (CK), adding 14C-straw (S), adding Ca14CO3 (C)] and soil respiration release CO2 and 14C-CO2 content were measured. The results showed that the mineralization of organic carbon in red soil, brown soil and black lime soil was promoted obviously by the addition of exogenous substances. The excitation effects of exogenous 14C-straw and Ca14CO3 on soil organic carbon mineralization were 28.7% , 46.2%, 15.5% and 127.0%, 175.3% and 100.1%, respectively. The contents of Ca14CO3 in the soil were 40.4%, 48.4% and 19.6% respectively. The soil types and additives, Interactions had a significant effect on the stimulating effect of soil organic carbon mineralization, the contribution of foreign matter in soil apparent mineralization, the mineralization rate of soil organic carbon and the cumulative mineralization amount / rate of soil organic carbon. Therefore, the addition of exogenous organic matter and calcium carbonate changed the mineralization characteristics of soil organic carbon. For carbonate-bearing lime soil, the study on the mineralization and turnover of soil organic carbon and the assessment of its effect on atmospheric CO2 must consider the inorganic Contribution of carbonate.