抄録
It is interesting to note that investigations conducted at the Agricultural Experiment Station of Aichi Prefecture in connection with the problem of the "Effects of continuous manuring on soil fertility", the rice grains on plants supplied with compost suffered less damage from violent wind than plants fed with other kinds of fertilizers (Table 1, Fig. 1). This report deals with the factors that led to the reduction in damage in fields where compost fertilizing was in vogue, the results being briefly summarized as follows:- (1) It was observed that fungi were playng a more important role in the mechanism of such damage than frictional injuries to the grains. Sixteen species of saprophytes and parasites were isolated from the damaged grains. It is believed that wind damage is caused by friction of the wind and impact, associated with accelerated evaporation and dehydration. These are the primary mechanical injuries to the plant and grain, followed by invasions of various kinds of fungi, thus increasing the damage. (2) It was further observed that continuous application of compost helped tissue development and the mechanical building up of the rice plant body. In the epidermal tissue, compost fertilizing promoted the development of silicated cells (Fig. 3), thus almost doubling the analytical quantity of the silica content in the plant compared with those from fields in which compost fertilizing was not used (Table 2). Moreover, it was found that silica generally excites the various physiological activities of the rice plant. (3) Since many of the pathogenetic fungi on rice plant are of the cuticular infecting type, silicification of the epidermal tissues is especially advantageous as protection against fungal invasion. (4) It is thus concluded that rice plants supplied with silica (i. e. compost) suffer less from wind damage, owing not only to its physiologically healthy conditions of growth, but also because of its mechanically resistant construction against penetration and multiplication of infections fungi.
