Musannaf Ibn Abi Shaybah

It is narrated from Hazrat Nafi’ that Hazrat Abdullah used to give the verdict regarding the zakat of fruits and crops that for that which is irrigated by river or spring water, or by rainwater, or by means of a camel, the zakat is ‘ushr, that is, one out of every ten. And for that which is irrigated by means of a pond (by lifting and carrying water), the zakat is half of ‘ushr, that is, one out of every twenty.