On a shemittah year in Israel there are a number of solutions to ensuring Jewish farmers continue to farm and make a living.
With Heter Mechira, the Jewish land is temporarily sold to a non-Jew, allowing the Jewish farmers to continue to farm their produce and sell it. Regarding Otzar Bet Din, the Bet Din employs Jewish farmers to farm produce but the produce itself, being hefker, is not included in the pricing of the produce thereby allowing the "sale" of produce, since the consumers are merely paying for the labour to farm the produce but not the produce itself.
I heard that, in Israel, an estimate of the ratio between produce for Heter Mechira versus Otzar Bet Din is about 95 and 5% respectively.
Given the very different approaches, which is preferable: Heter Mechira or Otzar Bet Din?