´It was narrated that:` Mu'adh bin Jabal said: “The Messenger of Allah (ﷺ) sent me to Yemen and commanded me to take one-tenth of that which was irrigated by deep roots, and to take one half of one-tenth of that which was irrigated by means of buckets.”
Hadith Referenceسنن ابن ماجه / كتاب الزكاة / 1818
Hadith Gradingالألبانی:حسن صحيح | زبیر علی زئی:إسناده حسن
1؎: Both «سیل» and «غیل» have been mentioned for this reason, that in some narrations, in place of «غیل», there is «سیل». The meaning is that the crops produced by the water of «سیل» (flood) will have one-tenth (ushr) obligatory upon them, because they are similar to crops irrigated by rainwater.