Effect of sowing rate, nitrogen rate and application timing on grain yield and protein of short grain rice

Abstract

Key findings •• Very low plant populations can reduce grain yield, and increase grain protein and lodging. Sowing rates between 60 kg/ha and 120 kg/ha are recommended for Opus[PBR] and Koshihikari to achieve target plant populations of 75 to 150 plants/m2. •• Koshihikari reached its highest grain yield with minimal lodging and lower grain protein when nitrogen (N) application was split between permanent water (PW) and panicle initiation (PI). Plan for a 50:50 split N application between PW and PI and then use the NIR Tissue Test at PI to fine-tune the PI application. •• Opus[PBR] has a higher yield potential with lower lodging risk than Koshihikari and can therefore tolerate higher N rates, but this can also increase grain protein. To ensure grain protein is at the required levels, plan for a 70:30 split between PW and PI and use the NIR Tissue Test at PI before applying additional N.