What did Prophet Muhammad (peace be upon him) say about the Zakat due on a land irrigated by rainwater or natural water channels?
 Narrated Salim bin `Abdullah from his father:                     The Prophet said, "On a land irrigated by rain water or by natural water channels or if the land is wet due to a near by water channel Ushr (i.e. one-tenth) is compulsory (as Zakat); and on the land irrigated by the well, half of an Ushr (i.e. one-twentieth) is compulsory (as Zakat on the yield of the land)."