And the difference between what is obligatory in charity for what is watered by the sky or rivers or both, and between what is watered by buckets and waterwheels.
Sayyiduna Ibn Umar (may Allah be pleased with them) narrates from the Noble Prophet (peace and blessings be upon him) that he said: "For crops irrigated by rain, one-tenth is due as zakat, and for those irrigated by waterwheels or camels, one-twentieth is due as zakat."