2026 Volume 95 Issue 3 Pages 205-215
As a labor-saving crop, the introduction of grain maize into the single-cropping paddy rotation system in northern Japan is increasing. However, there is limited knowledge about its use in the multi-cropping systems in the warm southwestern regions. This study aimed to evaluate yields in both spring and summer planting, assuming its introduction into these multi-cropping areas. The three-year average yields for spring and summer planting were 908 and 522 g/m2, respectively. In spring planting, the yield of the relative maturity (RM) 115 hybrid was the highest, with some years exceeding 1000 g/m2. The results of this study suggested that yield in spring planting is vulnerable to insufficient sunlight at the initial reproductive stage and that the late-maturing hybrids (RM125) have a risk of lodging. In summer planting, within the timeframe allowing for full grain maturation, later-maturing hybrids resulted in higher yields than earlier-maturing ones, and by increasing planting density the yield was increased 25%. However, the maximum yield in summer planting (697-772 g/m2) was still lower than that in spring planting. Given its potential for labor-saving cultivation and high yields in spring planting, a new rotation system that incorporates this crop needs to be established for future large-scale multi-cropping farms.
