Those aren’t price supports. I’m not sure there are any price supports left, maybe for sugar and peanuts.
CRP acres are under contract for 10-15 years, and are subject to many rules. Natural habitat for animals has to be enhanced, and the land is accessible to the public. CRP acres are rented for public wildlife habitat, and to slow water runoff.
http://www.econlib.org/library/Enc/AgriculturalSubsidyPrograms.html
For 2018, see:
https://fas.org/sgp/crs/misc/RS22131.pdf