Seeding rate for the sorghum‐sudangrass hybrid (Sorghum bicolor Moench × Sorghum sudanense [Piper] Stapf.) in the mixed seeding cultivation with corn (Zea mays L.) under a partial tillage condition in Kyushu region, Japan

Abstract

In the Kyushu region of Japan, mixed seeding cultivation of corn and sorghum is promising as a labor‐saving cropping system that makes effective use of forage crop fields in the summer season. In this study, we tested a few levels of seeding rates of a sorghum‐sudangrass hybrid (SSH) in a mixed seeding with corn planted at the standard rate (6.67 plants m−2) under a partial tillage condition in fields where Italian ryegrass had been sown after manure application and its second crop had been harvested. Our results indicate that the appropriate seeding rate of SSH with corn under partial tillage to maximize both the corn yield in the first crop and the annual yield is 1 g m−2, irrespective of the manure application levels. At this rate, the annual yield from the mixed‐seeded plots of corn and SSH was 20% higher than that from plots on which corn was seeded alone.