Will Freeciv AI ever make farmland?

I noticed that Freeciv AI only irrigates plains and grasslands once, which results in irrigated land. However, even after AI players have researched refrigeration (allowing them to build supermarkets and create farmland), they do not further irrigate the land to produce farmland. Why is that?

I built a supermarket before gifting a city to an AI player, and although the AI player is fully developed (technologically, financially, and militarily), the AI never bothers to exploit the presence of the supermarket to produce more food by producing farmland.