Effect of nitrogen fertiliser rate and timing on grain quality parameters and protein composition of rice grown in south-eastern Australia

Nitrogen fertiliser is an important crop management practice used to increase yield. Growers use the previous growing history of a paddock to determine the correct nitrogen (N) rate, as there is no appropriate soil N test for rice. In south-eastern Australia, the total N rate is often split into two applications to reduce the risk of sterility induced by cold temperatures and high N uptake. This strategy involves a basal N application applied pre-permanent water (PW) and the second application following panicle initiation (PI). While previous research demonstrates that split N application (Pre-PW and PI) affects crop yield, data investigating the impact on grain quality is relatively sparse. Using the medium-grain, semi-dwarf rice variety YRM70, we compared the effect of eight N treatments (Five N rates applied pre-PW and three split treatments with the same total N rate) on grain quality parameters and protein composition. These data revealed increasing the rate of N applied pre-PW significantly increased whole grain yield (WGY; the proportion of whole grain expressed as a percentage of harvested grain), however, splitting the same total N rate into two applications reduced WGY.