Effect of Soil Type and Variety on Mineral Composition of Lowland Brown Rice

Abstract

In the previous paper, it was found that the peat soil of normal manuring, as compared with the strong gley soil of normal manuring, gave significantly high protein and ash content of lowland brown rice of 13 Hokkaido varieties and was also found that the early varieties, as compared with the late varieties, had a tendency of higher protein and ash content of the rice. Therefore, investigations have been further carried out to determine the influence of soil types, i.e. the strong gley soil (normal manuring and heavy manuring) and the peat soil (normal manuring), and the above-mentioned varieties on the phosphorus, potassium, magnesium, manganese, and iron content of brown rice. The peat soil of normal manuring gave significantly high phosphorus and magnesium content and low iron content on dry basis and high magnesium content and low iron content in ash by comparison with the strong gley soil of normal manuring or heavy manuring, or both. On the other hand, the early varieties, as compared with the late varieties, had a tendency of higher phosphorus, potassium, and magnesium content on dry basis and lower manganese content in ash. The phosphorus and magnesium content on dry basis showed significantly negative correlations with heading date and date of maturity and positive correlations with ripening mean temperature, and the manganese content in ash showed significantly positive correlations with heading date, date of maturity, and ripening period and negative correlation with ripening mean temperature.