While obligatory to the Orthodox as a matter of religious observance, observance of the rules of Shmita is voluntary so far as the civil government is concerned in the contemporary State of Israel. Civil courts do not enforce the rules. A debt would be transferred to a religious court for a document of prosbul only if both parties voluntarily agreed to do so. Many non-religious Israeli Jews do not observe these rules, although some non-religious farmers participate in the symbolic sale of land to non-Jews to permit their produce to be considered kosher and sellable to Orthodox Jews who permit the leniency. Despite this, during Shmita, crop yields in Israel fall short of requirements so importation is employed from abroad.