I'm not sure you're missing anything. Typically Op Center (and other programs I've used) lumps things together by field. So if you have more than one crop that needs to be separated out, then that's 2 fields (east and west for example) If you're saying more than one crop as in timing like something over winter and then something summer or double crop....then you have no choice. Field A is field A, it gets planted to this and this in one calendar year.