EXPLORATION OF EFFECTIVE IMPROVEMENT IN THE ACID SULFATE SOILS AND SELECTION OF INDICATOR WEEDY PLANTS FOR JUDGEMENT ON ACIDIFICATION PROCESS

酸性硫酸盐土壤有效改良探索及酸化过程判断指标杂草植物的选择

基本信息

批准号：
08456120
负责人：
ADACHI Tadashi
金额：
$ 4.86万
依托单位：
OKAYAMA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1998
项目状态：
已结题

项目摘要

The acid sulfate soils is one of the problem soils in the world. If they were to be reclaimed by appropriate methods, we expect to extend the acreage for feeding the more increased population in near future. The objectives of this research were to examine the acidification process of an acid sulfate soil from such a view point of soil water contents and biological activity, and evaluate the possibilities of utilization of indicator plants which suggest the improvement of the acidification of soils. The following are summaries of our results.From the investigation of soil water contents and their physical and chemical characteristics, it was found that acidification of soils proceeded under the progression of dryness of soils . Even if a decline in pH value of soil was parallel with those in soil water contents at the period of immediately after drying, however, the specific range of soil water contents such as showing a striking low pH value appeared at a later periodIn the range of a … More remarkable decline of pH, the acidification of soils result from the increase of surfuric ions, concurrently a remarkable increase in the number of iron-oxidizing bacteria was found . In more higher range of soil water contents, even if we observed only the exist of iron-oxidizing bacteria, an increase in the number of them had not occurred with the passage of time . While under more dryness conditions, it was not suitable conditions for feeding the iron-oxidizing bacteria.Since the activity of iro-oxidizing bacteria was higher under such circumstances that the, initial salt concentration of soil was lower, the above-mentioned phenomenon with oxidation process, even if final step when Pyrite was oxidized was the same situation, occurred the more remarkably the less the initial salt concentration of soil.Those fundamental studies suggested that it was more effective to improve the acid sulfate soil by the application of lime after soil was oxidized sufficiently under plastic limit conditions which indicated acute development of acidity at an initial dryness period.On the other hand, the research on selection of indicator plants was carried on to clarify the adapted pH conditions of several weeds for their growth, and their range of adaptation in acidic soils. As a result, Phragmites australis, Schoenoplectus validus, Hydrocotyle umbellala and H.verticillata seemed to be possible to use as an indicator plant, especailly in highly acidic soils under wet conditions, while the gramineous weeds such as Miscanthus sinensis, Imperata cylindrica and Zoysia japanica under upland conditions . Less

酸性硫酸盐土壤是世界上有问题的土壤之一，如果通过适当的方法进行修复，我们预计在不久的将来可以扩大其种植面积，以养活更多的人口。这项研究的目的是检查酸化情况。从土壤含水量和生物活性的角度对酸性硫酸盐土壤进行了处理，并评估了利用指示植物改善土壤酸化的可能性。以下是我们的结果总结。土壤通过对水分含量及其理化特性的研究，发现随着土壤干燥的进行，即使土壤pH值的下降与干燥后土壤水分含量的下降平行，然而，后期出现了土壤含水量的特定范围，例如呈现出惊人的低pH值，在pH值显着下降的范围内，土壤酸化是由于硫离子的增加而导致的，同时土壤的酸化程度也显着增加。的数量在较高的土壤含水量范围内发现了铁氧化细菌，即使我们仅观察到铁氧化细菌的存在，它们的数量也不会随着时间的推移而增加。由于在土壤初始盐浓度较低的情况下，铁氧化细菌的活性较高，因此随着氧化过程的进行，即使最终铁氧化细菌的活性较高，上述现象也会随着氧化过程的发生而发生。步同样的情况下，土壤初始盐分浓度越低，黄铁矿的氧化发生越强烈。这些基础研究表明，在塑限下土壤充分氧化后，施用石灰对酸性硫酸盐土壤的改良更为有效。另一方面，进行了指示植物的选择研究，明确了几种杂草生长的适应pH条件以及它们在酸性土壤中的适应范围。因此，芦苇、Schoenoplectus validus、Hydrocotyle umbellala 和 H.verticillata 似乎可以用作指示植物，特别是在潮湿条件下的高酸性土壤中，而禾本科杂草如芒草、白茅和结缕草等高原条件下较少。