Muhammad bin Bakr bin 'Uthman al-Barsani محمد بن بكر بن عثمان البرساني · The Chapters Regarding Zakat

the Messenger of Allah (ﷺ) said: “For crops that are irrigated by the sky (i.e. rain) and springs, one-tenth. For those that are irrigated by watering, one half of one-tenth.”