Career change to agriculture?

I have an IT degree with experience in programming and sales, but I've become interested in agronomy, soil/crop science, plant biology, GIS/remote sensing. Jobs that interest me are precision agriculture, field agronomist, sales agronomist (or anything in sales), soil conservation, .

Is it possible to break into the field without an agronomy degree, or would I have to go back to school? How hard is it to find the first job in this field?