Tax-free zones in domains?

Ok, so what happens when my PCs establish a constitutional right of the peasantry to be free from taxes on their produce? I.e., anything they grow or raise is theirs to keep.

Is this covered under “land income” or “tax income”?

How do lower taxes effect a domain? Does abolishing taxes (wholly or partially) put more money “into the market”, so to speak, possible improving the local market class?

My players just engineered a coup in a city state to unseat a tyrant and establish a constitutional monarchy (consisting of a former bandit king—now real king—and his troops, a unicameral legislature consisting entirely of the landed aristocracy/previous merchant oligarchy, and a semi-independent/autonomous farmer’s/peasants council), and the peasants’ demands have included partial freedom from taxation on certain goods.

The urban domain should still function as written, and I can simulate lower tax income easily enough for the domain holder, but I’m wondering what greater noticeable effects I might be able to include once these new laws come into effect.

Should this simply be modeled by a tax rate of 0gp/family/month, or should it have an effect on land value income or service income as well?

Who owns the land? If the aristocrats still do, they should probably still take rent for it from the peasantry. Then the king would tax the aristocrats’ rent income.

In a domain with less taxes and more rights to the peasants, you’ll probably have enterprising peasants flocking in from nearby domains.

I’d probably just model it as 0 gp/family/month, with an extra morale bonus for the fact that it’s guaranteed, and an extra penalty to morale if taxes are ever raised above 0 for this guarantee being broken (without having a reason like a justified war that the peasants are behind). You’ll get the “peasants flocking in” as part of the morale increase, on average, so that part works out as expected.

according to the rules, standard taxes are 2gp/family/month and lowering that is worth +1 to morale checks per 1gp below normal. therefore the bonus would likely be a constant +2. This would also model the peasants flocking to the region because it would likely result in an uptick in the ongoing morale level, and levels above 0 result in extra immigration.

Jard has provided the official answer as well as I could! Thanks for the speedy response.

If you want something more radical, you can certainly play with the Land Values, Tax Rates, and so on if desired. All sorts of possibilities exist to tweak the framework.