@anon763
i think of it like this, kuuko was the God of agriculture, but her power can't manipulate rain, so maybe she only has a power over the soil, which if there's a flood there's nothing she can do to "protect" the plants
damn Yukime, you call that romantic? welp, maybe it is, in a depressing way
She's a god of agriculture, not the god of agriculture.
Japanese gods are more minor spirits of random things than anything, aside from the big shots that go down in legend they generally aren't very powerful. On the flip side they're also basically everywhere. It's the Land of Eight Million Gods after all.
Generally encouraging good harvest is probably something she can handle without a problem but a freak incident of nature wouldn't be something she can just wish away depending on the cause. Maybe if it was gradual it would've been prevented but this sounds like sudden famine.