THE PHYSICAL STRUCTURE OF CASTS OF MILLSONIA-ANOMALA (OLIGOCHAETA, MEGASCOLECIDAE) IN SHRUB SAVANNA SOILS (COTE-DIVOIRE)
THE PHYSICAL STRUCTURE OF CASTS OF MILLSONIA-ANOMALA (OLIGOCHAETA, MEGASCOLECIDAE) IN SHRUB SAVANNA SOILS (COTE-DIVOIRE)
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DOI：
10.1016/0016-7061(93)90104-s
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发表时间：
1993-03-15
期刊：
影响因子：
6.1
通讯作者：
LAVELLE, P
中科院分区：
文献类型：
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作者：
BLANCHART, E;BRUAND, A;LAVELLE, P
Millsonia anomala 是一种热带食地蚯蚓，主要负责兰托（科特迪瓦）上层土壤（Ferralsol）结构的形成和保护。它对土壤有机质动态的作用非常重要，因为水稳定铸体中的有机物受到保护，免受矿化。本研究旨在描述这些铸体的物理结构，以解释通过铸体结构对有机物的保护，并强调蚯蚓对土壤结构的作用。测量了铸体的孔径分布（汞孔隙率测定法）和堆积密度，并使用薄片和扫描电子显微镜观察对铸体进行了研究。对在灌木稀树草原土壤表面和蚯蚓培养物中收集的粪便进行了分析。结果表明，M. anomala 的粪便非常致密（堆积密度范围为 1.8 至 2.0 g cm-3），并且它们具有大量直径约为 10 的孔隙。 10 妈妈。在外面。这些铸件显示出一层致密的约。 25 妈妈厚。该皮质由细颗粒组成，预计会阻碍水和空气的流动。这种特殊的物理结构可以解释其他作者观察到的有机物质在铸件中的保护作用。
A tropical geophagous earthworm species, Millsonia anomala, is mainly responsible for the formation and the conservation of the structure of the upper horizons of soil (Ferralsol) at Lamto (Cote d'Ivoire). Its action on soil organic matter dynamics is important as organic matter in their water-stable casts is protected against mineralization.This study aims at describing the physical structure of these casts in order to explain the protection of organic matter through the cast structure and to emphasize the role of earthworms on the soil structure.The pore size distribution (mercury porosimetry) and the bulk density of casts were measured and casts were studied using thin sections and scanning electron microscopy observations. Casts collected at the surface of a shrub savanna soil and from earthworm cultures were analysed.The results show that casts of M. anomala are very dense (bulk density ranges from 1.8 to 2.0 g cm-3) and that they have an important volume of pores with a diameter of ca. 10 mum. On the outside. these casts display a dense layer of ca. 25 mum thick. This cortex consists of fine particles and can be expected to impede water and air movements. This particular physical structure may explain the protection of organic matter in casts, that has been observed by other authors.