Sayyiduna Attab bin Asid (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) used to send assessors to estimate their grapes and fruits.
In a narration of Imam al-Shafi'i (may Allah have mercy on him): He (peace and blessings be upon him) used to send those who would estimate the people's grapes and fruits.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7431