The size of lime material is vital for the efficiency of ameliorating soil acidity, thereby influencing soil biochemical processes. However, the effects of different sized lime material application on soil organic carbon (SOC) mineralization are yet to be elucidated. Therefore, a 35-day incubation experiment was conducted to determine the effects of three particle size fractions (0.5 to 0.25, 0.25 to 0.15, and < 0.15 mm) of dolomite on SOC mineralization of two acidic paddy soils. CO2 emission was increased by 3–7%, 11–21%, and 32–49% for coarse-, medium-, and fine-sized dolomite treatments, respectively, compared to the control in both soils. They also well conformed to a first-order model in all treatments, and the estimated decomposition rate constant was significantly higher in the fine-sized treatment than that of other treatments (P < 0.05), indicating that SOC turnover rate was dependent on the dolomite size. The finer particle sizes were characterized with higher efficiencies of modifying soil pH, consequently resulting in higher dissolved organic carbon contents and microbial biomass carbon, eventually leading to higher CO2 emissions. The results demonstrate that the size of dolomite is a key factor in regulating SOC mineralization in acidic paddy soils when dolomite is applied to manipulate soil pH.

中文翻译：

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白云石改良剂对土壤有机碳矿化的影响取决于白云石的大小

石灰材料的大小对于改善土壤酸度的效率至关重要，从而影响土壤生化过程。然而，不同大小石灰材料的应用对土壤有机碳（SOC）矿化的影响尚待阐明。因此，进行了一个为期35天的培养实验，以确定白云石的三种粒径分数（0.5至0.25、0.25至0.15和<0.15 mm）对两种酸性稻田土壤SOC矿化的影响。与两种土壤相比，粗，中和细粒白云石处理的二氧化碳排放量分别增加了3–7％，11–21％和32–49％。它们在所有处理中也都很好地符合一阶模型，并且细粒处理中的估计分解速率常数显着高于其他处理（P < 0.05），表明SOC转换率取决于白云石的大小。较细的颗粒具有较高的土壤pH调节效率，因此导致较高的溶解有机碳含量和微生物生物量碳，最终导致较高的CO2排放量。结果表明，当白云石用于控制土壤pH值时，白云石的大小是调节酸性水稻土SOC矿化的关键因素。