how to get 100% on rice field

Rice is tedious, with the water level, but pretty straightforward, though I don't manage to get 100% yield on it. I'm stuck at 87/90% (I don't know why I have 87% on some spots).

What do I have to do on rice field?

Noting that nothing is appearing on field info (like when it sometimes show a field should be rolled for example)

Edit : I had to lime the fields even though the game doesn't tell you it need to be limed