Growth of Paddy Rice Seedlings Using Controlled Fertilizers in 13 mm and 16 mm Thick Rock Wool Molding Medium

Abstract

Cultivation of paddy rice on rock wool molding medium is useful for reducing the weight of soil molding and saving labor. The growth characteristics of paddy rice seedlings cultivated using the new standard 13 mm thick rock wool molding medium (molding medium) and the conventional 16 mm molding medium were examined using the controlled fertilizer, i.e., NAEBAKOMAKASE. There was no significant difference between the following characteristics of paddy rice seedlings cultivated in the two molding media: height of plants, number of roots (total number of seminary root and crown root), dry weight of above-ground and underground parts, and the strength of seedling mats. It was estimated that 877-1111 g of fertilizer per nursery box was needed to secure proper soil covering (5–7 mm) applying the NAEBAKOMAKASE fertilizer to the 13 mm molding medium. Therefore, the 13 mm molding medium is expected to be 1.2–1.5 times more effective than the 16 mm molding medium.