The Fundamental Studies on the Development of High Performance Soil

由于土壤通常位于室外，直接受环境影响，很难人为控制土壤微生物的反应。我们着眼于土壤的许多重要功能都来自于化学反应，特别是生物化学反应，而这些反应又是由土壤微生物来完成的这一事实。本研究首先从土壤化学的角度考察土壤微生物生态，然后选择控制微生物生态或存活的因素。在获得这些知识后，我们开发了实验技术，通过应用微生境材料，例如微孔陶瓷作为土壤微生物的生境，在一定程度上控制土壤中的生化反应。通过这些实验，我们已经澄清，微生物的化学和水分条件的强烈影响，然后，一个实际的应用程序作为一种预防技术，硝酸盐淋溶在高地土壤中设计的只有埋在底土中的有机物料具有高的碳-氮比。另一方面，成功地建立了土壤接种细菌的方法。所用的细菌菌株是少动鞘氨醇单胞菌SS 86，它具有独特的需氧同化γ-HCH的能力，已知该细菌在简单接种到土壤中后会迅速消失，而在每年施用γ-HCH的土壤中土生土长的同化γ-HCH的少动鞘氨醇单胞菌则存活下来并定居下来。然而，发现菌株SS 86在被引入到在细菌接种之前已经接触过γ-六氯环己烷的土壤中后，能够在土壤中生长，其在土壤中的动态与土著γ-六氯环己烷同化少动链球菌的动态相同。使用选择性底物被认为是一种新的有效建立接种细菌的方法

Since soils being located normaly in outdoors they are directly exposed to the influence of environment, it is very difficult to control artificially the reaction of soil microorganisms. We have focused to facts that many important functions which human being has expected for soils come from chemical reaction, especially bio-chemical one and that these reactions are carried out by soil microorganisms In this study we have started experiments firstly to examine the microbial ecology from the aspect of soil chemistry and then to select factors controlling the ecology or survival of microorganisms. Having acquired these knowledges, we have developed experimental technologies to control to some extent the bio-chemical reaction in soil by the application of the microhabitat materials, for example, micro-porous ceramics as a habitat for a soil microorganism. Through these experiments, we have clarified that microorganisms were strongly influenced by chemical and moisture conditions, and then, a practical application as a preventive technique of nitrate leaching in upland soil was devised by only burying organic materilas with high carbon-nitrogen ratio in subsoil. On the other hand, a succeeful method to establish an inoculated bacterium in soil was developed. The bacterial strain used was Sphingomonas paucimobilis SS86, which has a unique ability to aerobically assimilate gamma-HCH.The bacterium has been known to disappear rapidly when simply inoculated into soils, whereas the gamma-HCH-assimilating S.paucimobilis indigenous to the soil where gamma-HCH has been annualyly applied survives and becomes established. However, strain SS86 was found to establish itself when introduced into a soil which had been exposed to gamma-HCH before bacterial inoculation, showing the same dynamics in the soil as shown by the indigenous gamma-HCH assimilating S.paucimobilis. Use of a selective substrate was suggested to be a new method effective for establishing inoculated bacteria in soi