Shulchan Aruch: Hoshen Mishpat 231

Shulchan Aruch: Hoshen Mishpat 231 23) It is forbidden to do commerce in the land of Israel in produce that sustains life. Instead, this (farmer should) bring from his granary, and sell, and this from his granary and sell, in order that they should sell cheaply. And in a place where there is an abundance of oil, it is permissible to trade in oil 24) It is forbidden to store up fruits (produce) that sustains life in the Land of Israel or in a any place in which Israel is the majority. In what situation are we referring to? When the fruits are taken form the marketplace. But storing what one has grown oneself is permissible. And in a year of famine, it is only permitted to store a year’s supply for one’s family. 25) Whoever speculates on the price of basic food or stores up fruits in the Land of Israel is like someone who lends with interest 26) It is forbidden to export produce that sustains life in the land of Israel to outside the Land or (even) to Syria, and not from the realm of one king to another king in the land of Israel