Effect of Soil Type and Variety on Protein, Fat and Ash Content of Lowland Brown Rice

[摘要] In the previous papers, it was found that the rice producing district in Hokkaido had a significant effect upon chemical composition of lowland brown rice and was suggested that the paddy field of peat soil brought especially about the high protein content. Therefore, investigations have been carried out to determine the influence of soil types, i.e. strong gley soil (normal manuring and heavy manuring) and peat soil (normal manuring), and varieties, i.e. 13 Hokkaido varieties from early-maturity to late-maturity, on the protein, fat and ash content of lowland brown rice. Compared with the strong gley soil of normal manuring, the strong gley soil of heavy manuring and the peat soil of normal manuring gave significantly high protein and ash content. As to the results, the high protein value by the peat soil may be due to the liberation of nitrogen by decomposition of the soil at the late growing period, whereas the high protein value by the strong gley soil of heavy manuring may be due to the heavy nitrogen manuring and further to the lower yield because of lodging during the ripening period. On the other hand, the early varieties, as compared with the late varieties, had a tendency of higher protein and ash content, and the protein and ash content showed significantly negative correlations with heading date and date of maturity and positive correlations with ripening mean temperature.

[学科分类] 农业科学（综合）