What is the minimum taxable amount (nisab) for camels that graze in the wilderness for six months or less, and are then fed for the remainder of the year from irrigated crops, and is zakat obligatory upon them?

According to the majority of scholars, zakat is not obligatory on camels that are fed, even though they differ on the duration of feeding that exempts them from zakat, contrary to the Malikis. So, if the camels are not pasturing for most of the year, there is no zakat on them. However, if they are pasturing for most of the year, then zakat is due on them according to the Hanbalis and Hanafis. The Shafi'is hold that there is no zakat on them unless they are pasturing for the entire year.