Is Zakat obligatory upon heirs who own agricultural lands in partnership with other heirs, where these lands are cultivated under a system of two-thirds for the farmer and one-third for the owner, and what about the Zakat for past years that was not paid?

The sharecropping contract is valid. Regarding the zakat on grains, both the worker and the owner must pay zakat on their respective shares if it reaches the nisab, which is five awsuq. Thus, the farmers must pay zakat on their share (two-thirds) if it reaches the nisab, and the heirs must pay zakat on their share of the one-third (the owner's share) if each individual's share reaches the nisab. This zakat is not forfeited by the passage of time; therefore, it is obligatory to investigate and pay the zakat for every year in which the share reached the nisab. The obligatory amount is half a tenth if the land is irrigated by machinery, and one-tenth if it is irrigated without machinery. If the share does not reach the nisab, there is no zakat. If the father did not pay the zakat when it was obligatory upon him, it must be paid from his estate.