Experiments on the elution of manganese from soil and pot cultures were performed in order to determine what effects of calcium silicate application to the soil enriching manganese under the paddy field condition on the growth and manganese absorption of pasturage crops would appeare.
1). Amounts of manganese eluted from soil were suppressed by application of calcium silicate, due to the raising of soil pH and also of soluble silica concentration in soil.
2). Application of calcium silicate did not result in increasing of pasturage crops yields but rather in lowering of mangagese concentrations in plants. In the case of none phosphorous application, this
lowering effect of calcium silicate application of contents of manganese in plants was more noticeable.
3). Addition of silica sol to culturing solutions did not affect manganese concentration of pasturage crops but of calcium ion did.
4). Therefore, raising soil pH and soluble silica concentration in soil will result in decreasing the elution of soil manganese, especially of exchangeable mannanese. Calcium ion would have a direct, that is, antagonistic effect on the absorption of manganese by pasturage crops.