The are several basic qualifications to be eligible to enroll in CRP.
One of those is based on soil, water, or wind erosion. There are places that are very flat but qualify based on wind erosion. Any of those, wind, water, or soil are determined by NRCS , not fsa.
Continous practices bypass those determinations because of their location to water. Instead of waiting a year or 2 for a general sign up, those high priority locations move to front of the line.
Nationaly about 30% of crp is general whole fields, 30% continuous, and 30 is crp grassland. Crp grasslands rentals rates are much lower, but have less environmental benefits. It may have never been cropped, but is over grazed introduced and exotic grasses. But the eat up 1/3 of the total crp acres.
Crp ain't perfect. But without it, 20 million more acres would be in production and the prices of committees would reflect a 20% change that farmers don't need.