Is the owner of the crops obligated to pay Zakat on the surplus if what is due from him is more than what the Zakat Collection Committee estimated?

Zakat is obligatory on what is produced from the earth. If it was irrigated by rainwater, springs, or was naturally irrigated (athari), then one-tenth is due. If it was irrigated by artificial means (nadh), then half of one-tenth is due. This is when it reaches the nisab (minimum threshold). If it is estimated that the committee underestimated the crop, then the owner must pay zakat on the surplus, whether it reaches the nisab or not.