Musannaf Ibn Abi Shayba 13:2403

Abu Bakr narrated to us, he said: Mu'adh narrated to us, from 'Imran ibn Hudayr, from al-Rudayni, from Yahya ibn Ya'mar, that 'Umar used to lease [land] and stipulate that [the lessee] should not fertilize it with dung.