Study on change of soil and soil layers in rice field by modern farming technique and state of consolidation of field foundation

降低我国稻田水稻生产成本势在必行。要实现快速发展的低成本，提高劳动生产率，必须采用不同于常规水稻的种植技术。有必要引进以直播、免耕为代表的新技术，向水稻种植转变。本研究的目的是建立新技术的稻田基础条件。调查田为实施现代水稻种植的稻田如下：--实行免耕的稻田(秋田县)--实行翻耕直播的稻田(千叶县)--实施免耕直播的稻田(冈山县)--冈山县和千叶县实施旱田直播的稻田，旱田条件下的可加工性得到了改善，没有使产量如此下降，而且似乎是劳动生产率的最爱。并对旱种稻田地基加固的注意事项进行了整理。以秋田县八郎免耕为例，产量没有下降，生产力有所提高，各种生物栖息在稻田里，考虑到生态系统是种植的方式。免耕直播稻田土壤结构的改善和土壤物理性质的改善，与移栽栽培相比，在生产力上不存在问题。今后，新的种植方式与稻田土壤的关系，特别是要把握土层结构及其特性的变化，或采取生态系统的变化。

It is necessary that the production cost reduces for the paddy field rice crop in our country. The growing technique which is different from the conventional rice crop is necessary to do the becoming of the low cost which progress rapidly and for the labor productivity to improve. It is necessary to introduce the new technique which is represented by direct seeding and no-tilled cropping which should change to the rice paddy planting.The purpose of this study is the establishment of the state for where the rice field basis to the new technique is desirable. The investigation field were the rice field implementing the modern rice crop growing as follows :- The rice field which is implementing no-tilled cropping (Akita prefecture)- The rice field which is implementing plowing and direct seeding (Chiba prefecture)- The rice field which is implementing no-tilled and direct seeding (Okayama prefecture)In the case in Okayama and Chiba prefecture which is implementing dry rice field direct seeding, the workability in the dry rice field condition improved, didn't make yield so decline, and it was seemed favorite from the labor productivity. Also, the attention point of consolidation of foundation as dry seeding rice field, too, was put in order. By the case of no-tilled cropping at Hachiro-gata, Akita prefecture, the yield didn't decline and the productivity was improving, the various creatures are inhabiting the paddy field, and it was the way of growing to have considered the ecosystem. By also the rice field of no-tilled direct seeding, There are progress of the soil structure and improvement of the soil physical properties, there was not a problem in the productivity compared with the transplantation growing of the practice.Of the future, The relation between the new way of growing and the rice field soil, especially, grasp the change of the soil layer structure and its characteristics, or the change of the ecosystem must be taken.