7 C.F.R. § 2100.052
(a) Cover crop standards. To qualify for the cover crop practice under this part, field(s) or management unit(s) must be managed according to the following standards:
(2) When a leguminous cover crop is used individually or as part of a mix, the farm producer must develop a nutrient budget which demonstrates:
(b) Cover crop recordkeeping standards. Farm producers must maintain records for 5 years demonstrating required implementation of the cover crop practice. Records must contain sufficient detail to be readily understood and auditable. Records may be of varying types and origins including, but not limited to, physical documentation (for example, paper forms, invoices, receipts, seed tags), digital files (including from farm management software), data generated by farm equipment (for example, precision agriculture equipment), remotely sensed data, georeferenced and timestamped photographs, or data and records used for participation in USDA programs. Records must demonstrate: