Musannaf Ibn Abi Shayba 28:190

Muhammad ibn Fudayl narrated to us, from Husayn, from ‘Amr ibn Maymun, who said: I came and ‘Umar was standing over Hudhayfah and ‘Uthman ibn Hunayf. He said: "Do you both fear that you have burdened the land with what it cannot bear?" Hudhayfah said: "If I wished, I could have doubled [the tax of] my land." He said: And ‘Uthman ibn Hunayf said: "I have burdened my land with a matter that it is capable of bearing, and there is not much surplus in it." He said: "Look into what you have, lest you have burdened the land with what it cannot bear."