One recurring element in Love Kome: We Love Rice is the idea of a "Harvest Show", which is something that Hinohikari (our protagonist) desperately wants to be a part of. I had previously understood this to be some sort of rice-based performance art, judging from what we'd seen of the Hinohikari / Akitakomachi / Nikomaru cross-dressing idol unit. (Yes, if you thought you'd seen everything, come watch Love Kome for an idol unit composed of cross-dressing personified rice varieties.)
However, in episode 5, Sasanishiki stops a bullet train from running over a conveniently-placed dog by means of what onlookers (Hinohikari and friends) describe as a "Harvest Show". (It is unclear how creating a few ears of rice helped anything here, but this is anime, so whatever.)
An insert song (titled "Fine Dress") does play in the background as he leaps from the roof of the school (summoning, in the process, a jelly donut rice ball), but he's not actually singing it in-show.
So basically I no longer have any idea what a Harvest Show is in this anime.