Different effects of single versus repeated additions of glucose on the soil organic carbon turnover in a temperate forest receiving long-term N addition
Different effects of single versus repeated additions of glucose on the soil organic carbon turnover in a temperate forest receiving long-term N addition
复制标题
DOI：
10.1016/j.geoderma.2019.01.032
复制
发表时间：
2019-05
期刊：
影响因子：
6.1
通讯作者：
Qingkui Wang;Longchi Chen;Qingpeng Yang;T. Sun;Changmeng Li
中科院分区：
文献类型：
--
作者：
Qingkui Wang;Longchi Chen;Qingpeng Yang;T. Sun;Changmeng Li
来自凋落物分解和根系周转的不稳定有机碳输入可能通过启动效应刺激土壤有机碳（SOC）分解，从而强烈影响SOC动态。这种启动效应的方向和大小取决于N和C添加的类型和模式。然而，在何种方式的N和C添加的类型和模式影响引发效应仍然知之甚少。因此，我们进行了90天的培养，以评估单一和重复添加13 C-标记的葡萄糖对SOC分解的影响，这些SOC分解是从长期模拟N实验中收集的，无机或有机N以100 kg N hm-2 yr-1的速率添加为溶液形式。测定呼吸CO2及其δ 13 C值，计算添加的葡萄糖和天然SOC分解，从而定量分析初始碳，以及初始SOC和保留葡萄糖-C之间的净碳平衡。我们首次发现，长期的N添加显着减少了累计引发C的平均23.0%，但这种减少是在有机氮（29.7%）比无机氮（16.3%）。因此，单独添加无机氮可能会低估大气氮沉降对初始碳的抑制作用。单次添加葡萄糖诱导的累积启动C量是重复添加葡萄糖诱导的2.92倍。这一发现表明，单次添加大量不稳定的有机碳可能高估了田间自然发生的引发碳。还观察到葡萄糖添加模式和N添加对引发C的组合效应。在90天的培养后，添加的葡萄糖-C的量，仍然在土壤中是显着高于SOC的损失，由于积极的启动效应，导致净C增加。综合所有数据，我们得出结论，反复添加不稳定的有机碳增加大气氮沉降下的土壤可以增加SOC封存和股票，尽管在温带森林的积极启动效应。
Labile organic C inputs from litter decomposition and root turnover may stimulate soil organic carbon (SOC) decomposition by a priming effect that strongly influences SOC dynamics. The direction and magnitude of this priming effect depends on the type and pattern of N and C addition. However, in which manner the type and pattern of N and C addition affect priming effect remains poorly understood. Thus, we conducted 90-day incubation to evaluate the effects of single and repeated addition of13C-labeled glucose on SOC decomposition to soils collected from a long-term simulated N experiment with inorganic or organic N addition as the rate of 100 kg N hm−2yr−1as solution form. Respired CO2and its δ13C value were measured to calculate the added glucose and native SOC decomposition, and consequently quantify primed C, and net C balance between primed SOC and retained glucose-C. We revealed for the first time that long-term N addition significantly decreased the cumulative primed C by an average of 23.0%, but this decrease was greater under organic N (29.7%) than under inorganic N (16.3%). Therefore, the suppression effects of atmospheric N deposition on primed C may be underestimated by solely adding inorganic N. The amount of cumulative primed C induced by single glucose addition was 2.92 times as high as that induced by repeated glucose addition. This finding suggests that the single addition with a high amount of labile organic C may overestimate primed C that naturally occurs in the field. A combined effect of glucose addition patterns and N addition on primed C was also observed. After the 90-day incubation, the amount of added glucose-C that remained in soils was substantially higher than the SOC loss due to positive priming effect, resulting in a net C increase. Taken together all data, we conclude that the repeated addition of labile organic C to soils under increasing atmospheric N deposition can increase SOC sequestration and stocks despite the positive priming effects in temperate forests.