Musannaf Ibn Abi Shaybah

Hazrat Ibn Jurayj says that I asked Hazrat Ata: A man has crops, but he owes more debt than his wealth. Then his crops are harvested—on the day the crops are harvested, should he pay the due (zakat)? He replied: For one who owes more debt than his wealth, we do not consider that zakat is due on his livestock and fixed assets. However, on the day his crops are harvested, whatever is due upon him on that day, he should pay.

Hazrat Abu Zubair says that I heard Hazrat Tawus say that there is no zakat on it.