Disruption of soil aggregates by varied amounts of ultrasonic energy in fractionation of organic matter of a clay Latosol: carbon, nitrogen and δ13C distribution in particle‐size fractions
Disruption of soil aggregates by varied amounts of ultrasonic energy in fractionation of organic matter of a clay Latosol: carbon, nitrogen and δ13C distribution in particle‐size fractions
复制标题
DOI：
10.1046/j.1365-2389.2000.00321.x
复制
发表时间：
2000-09
影响因子：
4.2
通讯作者：
R. Roscoe;P. Buurman;E. Velthorst
中科院分区：
文献类型：
--
作者：
R. Roscoe;P. Buurman;E. Velthorst
在研究土壤有机质（SOM）时，超声波能量被广泛用于在物理分级土壤之前破坏土壤团聚体。然而，关于破坏土壤所需的最佳能量没有共识。因此，我们的目的是（i）量化不同的超声波能量对每个颗粒大小的恢复及其C，N和δ 13 C分布的影响，以及（ii）确定破碎特定土壤SOM的理想能量。我们的研究结果表明，2000-100 μm的粒径部分主要由不稳定的聚集体和100-2 μm的稳定聚集体组成。260-275 J ml−1的能量足以破坏大多数不稳定的聚集体并留下稳定的聚集体。使用这种阈值能量结合粒度分级并不满足所有目的，因为在同一池中回收了> 100 μm的稳定聚集体中存在的垃圾样物质和相对不稳定的有机碳。825 J ml−1的超声波能量不足以稳定土壤质量和有机质在颗粒级分之间的再分配，但在能量超过260-275 J ml−1时，相对稳定的团聚体会破碎，并导致粘土级分中具有不同性质的碳的混合物。
Ultrasonic energy has been widely used to disrupt soil aggregates before fractionating soil physically when studying soil organic matter (SOM). Nevertheless, there is no consensus about the optimum energy desirable to disrupt the soil. We therefore aimed (i) to quantify the effect of varied ultrasonic energies on the recovery of each particle‐size fraction and their C, N and δ13C distribution, and (ii) to determine an ideal energy to fractionate SOM of a specific soil. Our results show that the 2000–100 μm particle‐size fraction was composed mainly of unstable aggregates and the 100–2 μm fraction of stable aggregates. Energies of 260–275 J ml−1 were sufficient to disrupt most of the unstable aggregates and leave stable aggregates. The use of this threshold energy combined with particle‐size fractionation was not satisfactory for all purposes, since litter‐like material and relatively recalcitrant organic carbon present in stable aggregates > 100 μm were recovered in the same pool. An ultrasonic energy of 825 J ml−1 was not sufficient to stabilize the redistribution of soil mass and organic matter among particle‐size fractions, but at energies exceeding 260–275 J ml−1 relatively stable aggregates would fall apart and cause a mixture of carbon with varied nature in the clay fraction.