RESEARCH REPORTS FROM INSTITUTE FOR AGRO-MICROBIOLOGY, Vol. 9, 2005 p.7-25
Copyright © Institute for Agro-Microbiology. All Rights Reserved.

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ORIGINAL ARTICLE

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1.Soil Characteristics of Nature-Farming Fields

Tomoaki Kuwamura(Institute for Agro-Microbiology)

Chemical data of Nature-Farming soils which are analyzed for 5 years between 1992 and 1996 fiscal year are classified three land category such as paddy field, ordinary upland field and greenhouse field, and analyzed statistically. Number of data of paddy field, ordinary upland field and greenhouse field are 654, 584 and 212 respectively. The thickness of cultivated soil is higher than that of fixed point investigation enforced by MAFF (The Ministry of Agriculture, Forestry and Fisheries of Japan). In paddy field and greenhouse field, total carbon (humus) is higher than that of MAFF data. It is suggested that there is a close relation between available nitrogen and total nitrogen. In some soil group or some classification of land category, correlations between available nitrogen and truog phosphate exist. In paddy field, there is a significant negative correlation between years of Nature-Farming continuation and truog phosphate, and base saturation degree. In non-volcanic ash soil of greenhouse field, there is a significant positive correlation between years of Nature-Farming continuation and truog phosphate, and base saturation degree. Ratio satisfying the level of improving target of available nitrogen is over 50% in every classification of land category. The ratio of truog phosphate is lower in paddy field, but higher in ordinary upland field and greenhouse field. As to base saturation degree of paddy field, 67% data is lesser than the lower level, however many data is over the higher level in ordinary upland field and greenhouse field, where it is suggested that organic matter is provided to the field excessively.

Keywords: Nature Farming, Soil diagnosis, Organic matter, Paddy field, Ordinary upland field, Greenhouse field