Is it obligatory to pay zakat on crops at the time of harvest, or is it permissible to delay its payment until after its value is known? And is the debt owed by the farmer deducted from the zakat on the crops?

Zakat on crops and fruits becomes obligatory immediately after harvest, as Allah Almighty says: "And give its due on the day of its harvest." It is not permissible to delay it except for a legitimate religious benefit. It is permissible to deduct debts incurred for the crop before Zakat becomes due, but not debts incurred for the family, or those incurred for the crop after Zakat becomes due, such as harvest expenses.