7 C.F.R. § 1470.6
(a) Eligible applicant. To apply for CSP, a producer must—
(c) Ineligible land. The following lands (even if covered by the definition of eligible land in § 1470.3) are part of the agricultural operation, but are not eligible for enrollment in CSP:
(1) Land enrolled in the Conservation Reserve Program (CRP), 7 CFR part 1410, unless—
(3) Land used for crop production after December 20, 2018, that had not been planted, considered to be planted, or devoted to crop production for at least 4 of the 6 years preceding that date, unless the land does not meet such requirements because that land—