How do I save a failing field in strange weather?

You manage most crops well, but a failing field under strange conditions still stumps you, and that is because you are being asked to read a situation the old rules were not written for. That is not ignorance. It is the edge of what anyone knows when the weather stops behaving. A failing field is telling you something, and the odd conditions are part of the message. You will not save it by doing harder what used to work. You save it by watching closely, testing small changes, and letting the field teach you what it needs now rather than what it needed last year. Pick one thing you can measure or change on a small patch, not the whole field. Try it, watch what happens, and let the result guide the next move. You may not save all of it. But careful attention to one corner tells you more than worry over the whole, and it is how the new rules get learned.