权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Studies on the perfection of radiography for soil macropores and on the application to the soil physical problems.

土壤大孔隙射线照相技术的完善及其在土壤物理问题中的应用研究。

基本信息

批准号：
62860027
负责人：
TOKUNAGA Koh-ichi
金额：
$ 6.72万
依托单位：
Faculty of Agriculture, Iwate University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research
财政年份：
1987
资助国家：
日本
起止时间：
1987 至 1989
项目状态：
已结题

项目摘要

1. Perfection of the macropore imaging method. (1) Undisturbed sampling of cubic form soil. Cubic form soil samples are suitable for x-ray stereoradiography, and in this study the square cylindrical sampler method and knife cutting method have been developed. These two methods are followed by soil sample trimming in the laboratory, and 4.15cm cube sample of undisturbed soil is obtained. (2) Infiltrating method of contrast medium into the sample. Clay plate coating of cubic sample and water saturation of sample were standardized, and the method was named "Drying method". This standardization raised the efficiency of contrast medium infiltration and the accuracy of macropore imaging.2. Application of the macropore imaging method. (1) In the fields of volcanic ash soils, it was found that macropores having shape of plant roots developed densely through the whole depth of tephra horizon. Further, the plants opals of native plants were detected simultaneously in the soils of whole horizon. These results indicate that the macropores would have been formed by the old plants roots. (2) The shapes of macropores infiltrated with water in the compacted soils were investigated using above method. Namely, after permeability test the water was replaced with contrast medium, and the sample soil was radiographed. At the low water content of soil, the interspaces of granulated units developed. However at the high water content, the membrane-like voids grew into horizontal direction. (3) In the farmland, the rice paddy field, upland field and grass land, macropores formed by the c rop roots grew vigorously. Among them, grass land shows the most active and deepest (1 m) development of those macropores. (4) Initially air entering voids of volcanic ash soils were visualized by the above method, and they were most thick macropores formed by the plants roots.

1.大孔隙成像方法的完善。(1)立方形土壤的原状取样。立方形土样适合于X射线立体照相，本研究发展了方柱取样法和刀切法。采用这两种方法进行室内土样修整，得到4.15cm立方体原状土样。(2)造影剂渗入样本的方法。对立方体试样的粘土板涂布和试样的含水饱和度进行了标准化，并将其命名为“干燥法”。标准化提高了造影剂渗透的效率和大孔成像的准确性.大孔隙成像方法的应用。(1)在火山灰土壤中，植物根系状的大孔隙遍布火山灰层的整个深度。此外，在整个土层中同时检测到了本地植物的植物蛋白石。这些结果表明，大孔隙可能是由老植物的根形成的。(2)利用该方法对压实土中大孔隙的形态进行了研究。也就是说，在渗透性试验后，用对比介质代替水，并对样品土壤进行射线照相。土壤含水量低时，颗粒单元的空隙发育。而在高含水量时，膜状孔隙向水平方向生长。(3)在农田、水田、旱地和草地中，根系形成的大孔隙生长旺盛。其中，草地显示这些大孔隙最活跃和最深（1 m）的发展。(4)用上述方法观察到的火山灰土壤孔隙中，空气进入的最大孔隙是植物根系形成的粗大孔隙。