[Well, it's not exactly high-level ninja work, but plenty of the genin missions Sakura's been on have involved work rather like this. Plus, from a medical standpoint, it makes good sense to have their own means of gaining fresh produce. Good not to rely on the Malnosso to feed them properly, after all.]

I'm afraid I don't have much knowledge of irrigation systems but I'd be glad to help with the farming when I have time off from the clinic.