Why would the rule of law be important for the farmers

Because farmers have been on the lower end of the social pyramid throughout history. This means everyone could have taken advantage of them if they had wanted to. No one was there to protect farmers through most history. However, when your lands are ruled by the rule of law, farmers are protected by the law which everyone has to abide by. If not the farmers can complain to the authorities or, nowadays, sue a person.

Government taxes ? i guess