Effects of new foliar-application fertilizer containing 5-aminolevlinic acid on yield increase of direct-sowing rice plants.

In Japan, the cultivation methods for rice plants (Oryza sativa L.) in paddy field can be mainly classified into two types, i.e. mechanical transplanting cultivation and direct-sowing. However, in the case of direct-sowing cultivation the grain number per m 2 becomes often an excess of 30,000 grains. As the result, the decrease of percentage of ripened grains takes places in inferior grains than in superior ones and, as a consequence, the grain yield decreases. In the present experiment, effects of foliar application fertilizer containing 5-aminolevulinic acid (5-ALA fertilizer: commercial name; Penta-keep) on the percentage of ripened grains in direct-sowing rice plants were examined. This 5-ALA fertilizer was sprayed at the heading stage of cvs. Koshihikari and Tenkomori, the promotive effect on the yield increase of grains was found in both the cultivars tested. It should be noted that the high yielding effects were at least in part supported by the increasing of grain filling in inferior grains and superior, especially in inferior grains. On the other hand, the excellent effect of 5-ALA fertilizer was found in the aerial spray by small automated helicopter. From all results, we emphasize that the application of foliar application fertilizer containing 5-ALA are very useful to achievehigh yield of direct-sowing rice plants.