What can AI predict?

So there are lots of things that machine learning can predict and we can point to examples of them running in the real world. Things like:

• image recognition of cat vs. dog
• stock market prediction
• is this a stop sign
• is it a tumor?

In short, these are all basically identifying trends, but what kinds of things can it not predict?

For instance, can we train AI to identify the best amendments to add to soil to improve crop yield? What about the best treatment for patients with a disease. We can go up to a point, but how far can it go?