Masruq (may Allah have mercy on him) narrates from Sayyiduna Mu'adh bin Jabal (may Allah be pleased with him); he said: The Messenger of Allah (peace and blessings be upon him) sent me to Yemen, "and ordered me to take from every adult one dinar or its equivalent in Ma'afiri cloth; and he ordered me to take from cattle, from every thirty a calf (tabi'), and from every forty a musinnah; and he ordered me to take a tenth ('ushr) from what is watered by the sky (rain) or is naturally irrigated, and half a tenth from what is watered by buckets."
Hadith Referenceالمعجم الكبير للطبراني / باب الميم / 17398