As a broader term maybe, but you can't deny the religious connotation of the word, especially under a theocratic regime. Also I am not entirely sure if the broader sense of the word would be obvious to Iranians, who do not speak Arabic (except in the southwest). I wonder if anyone who speaks persian can confirm that that they use jihad for struggle/effort outside of religion.

Would Minister of the Agricultural Crusade work better?

I agree with the religious connotation, but I think it's hard to separate anything from religious context in a theocracy. If everything is done in the name of that one singular purpose, every institution becomes an end towards that goal. In that sense I agree, that's what I meant with the lost nuance, but I wouldn't really go so far as to singly connect it to the holy war concept.

It’s probably akin to our “czars” when we declare “war” on some unwanted thing.

In the US government:

1. “czar” is an informal title, not an official title (the “Drug Czar” is formally titled “Director of the Office National Drug Control Policy”)

2. The “czar" informal title has nothing to do with a “war” (this is a false generalization from the Drug Czar and the War on Drugs), but with the position of coordinating policy for the executive branch for an effort that cuts across multiple cabinet level agencies.