Is zakat obligatory on an olive harvest shared between a landlord and a tenant if the combined amount reaches the nisab, but the share of neither party reaches it individually after division?

If the owner of an olive tree asks another person to tend to it and harvest its fruit in exchange for half of the produce, this is a permissible musaqat (sharecropping) contract. Zakat is obligatory on both of them if each one's share reaches the nisab. Scholars differ regarding the effect of khultah (mixing of ownership) in matters other than livestock; some mandate zakat if the total produce reaches the nisab, while others do not. However, if the owner asks someone to harvest the fruit in exchange for half, this is an ijarah (rental/wage) contract. In this case, if the contract is made after the fruit has ripened, the zakat is on the owner. But if it is made before the fruit has ripened, the contract is only valid on condition of immediate harvesting. If they agree to leave the fruit on the trees, then the ajir (worker) is liable for zakat on his share if it reaches the nisab after the fruit has ripened.