Studies on the macropore morphology of grassland soil determined by X-ray and contrast media.

本研究的目的是研究草地土壤中大孔隙的形态。从根成孔（有根孔）的普遍性、根成孔的实际条件、根成孔的形成时期、颗粒和团聚体成孔等方面对大孔的形态进行了研究。采集了国内外7个土壤样品。颗粒和团聚体的大孔主要来自石英砂、玻璃珠、土粒、土粒和蚯蚓的团聚体。孔隙形态分析表明，永久草地中几乎所有大孔隙的形状都是根状孔隙。颗粒和团聚体形成的孔隙由颗粒间和团聚体间组成，形态为球状或棒状。蚯蚓的聚集体形成的孔隙为海绵体的网状结构。在疏水保水带，除受蚯蚓和天气影响外，大孔由根孔组成。非毛管孔隙形态观察了安多土、重黏土和草原土中致密固体表层的根状孔隙。表层土壤根部孔隙方向呈水平和倾斜方向，而英国草原土和棕色森林土的下层土壤和下层土壤孔隙方向不明确。毛管孔的形态受表层密度层和砂层的根孔、颗粒间孔和团聚体间孔的影响。砂质土表层和下层均由颗粒间和团聚体间组成。在粘土中，所有大孔隙的形态都是由根孔形成的。根孔的形成期为3年。草原土壤大孔主要由植物根系形成的根孔组成，是草原土壤普遍存在的现象。

The purpose of this study is to examine the morphology of macropores in the grassland soils. The morphology of macropores was studied on the universal of the pore formed by roots (rooted pore), the actual condition, the formative period of the pore formed by roots, and pore formed by particles and aggregates. Soil samples were collected from seven domestic and overseas soils. The macropore of particles and aggregates was from quartz sand, glass beads, grain of Andsol, aggregates of the Andsol, and aggregates of earthworm. The morphology of pores showed that the shap of almost all macropores is the rooted pore in the permanent grassland.The pores formed by particles and aggregates were consisted of inter-particles and inter-aggregates, that morphology was a globular form or a rod-shaped form. The Pores formed by aggregates of the earthworm were network structure of the spongy body. In the drainage and water-retention zone, the macropore was consisted of the rooted pore except under the influence of the earth-worm and weather. The morphology of the non-capillary pores observed the rooted pore in the dense and solid sur-face soil layr in Andosol, heavy clay, and steppe soil. The pore direction was in the horizontal and slant in rootmat of the sur-face soil layr, but the sub sur-face soil and subsoil layr is not clear in the steppe soil and brown forest soil in England. The morphology of the capillary pores was shaped by the rooted pore, inter-particles and inter-aggregates in the density and sandy each surface soil layr. The sub sur-face soil layr and subsoil layr were consisted all inter-particles and inter-aggregates in the sandy soil. In the clay soil, all the morphology of macropores was shaped by the rooted pore. The formative period of the rooted pore was for three years. The macropores of the grassland soil consisted mainly of the rooted pore formed by plant roots, that was universal phenomenon in the grassland soil.