ORGANIC-CARBON DETERMINATION BY THE WALKLEY-BLACK AND DRY COMBUSTION METHODS IN SURFACE SOILS AND ANDEPT PROFILES FROM COSTA-RICA
ORGANIC-CARBON DETERMINATION BY THE WALKLEY-BLACK AND DRY COMBUSTION METHODS IN SURFACE SOILS AND ANDEPT PROFILES FROM COSTA-RICA
复制标题
DOI：
10.2136/sssaj1979.03615995004300010014x
复制
发表时间：
1979-01-01
影响因子：
2.9
通讯作者：
VASQUEZ, AJ
中科院分区：
文献类型：
--
作者：
BORNEMISZA, E;CONSTENLA, M;VASQUEZ, AJ
通过与干式燃烧设备的测定和释放的CO2的重量测定进行比较，研究了Walkley-Black方法氧化有机C的效率。对表层土壤 (50) (0-30 cm) 进行了研究，每组 10 个，每 1 个属于以下分类亚目中的 1 个：Fluvents、Andepts、Tropepts、Udults 和 Ustults。还分析了 17 个 Andept 剖面的样品，以研究氧化效率随深度的变化。表面样品的结果表明常用的转换因子有点太小。建议使用 75% 氧化作为转换为总碳的基础，因为 86% 的研究样品与该值的偏差小于 2%。更深地层中的有机物更容易通过沃克利-布莱克程序被氧化，这可能是因为植物残留物较少，并且有黄腐酸的积累。在某些情况下，氧化几乎完全。这种氧化变化相当大，并且与这些土壤的质地或 pH 值无关。氧化性的程度显然可以得出安德普剖面中层位相对年龄的结论，并表明埋藏层位的存在。
The efficiency of oxidation of organic C by the Walkley-Black method was studied by comparing with determinations using dry combustion equipment and gravimetric determination for the evolved CO2. Surface soils (50) (0-30 cm) were studied, in groups of 10, each 1 belonging to 1 of the following taxonomic suborders: Fluvents, Andepts, Tropepts, Udults and Ustults. Samples from 17 Andept profiles were also analyzed to study changes of oxidation efficiency with depth. The results for the surface samples indicated that the commonly used conversion factor was somewhat too small. It is recommended that 75% oxidation be used as the base for conversion to total C, as 86% of the studied samples deviated in < 2% from this value. The organic matter in the deeper horizons is more easily oxidized through the Walkley-Black procedure, perhaps because plant residues are less abundant and there is an accumulation of fulvic acids. In some cases the oxidation is almost complete. This oxidation is rather variable and it was not correlated with the texture or pH of these soils. The extent of oxidizability apparently can allow conclusions on the relative age of horizons in Andept profiles and indicates the presence of buried horizons.