(a) Offers for CRP contracts may be submitted only during signup periods as announced periodically by CCC, but not less often than once each year. Acceptability of otherwise eligible offers will be determined as provided in § 1410.31 .(b) Notwithstanding paragraph (a) of this section, CCC may hold a continuous signup for land to be devoted to particular uses. Generally, continuous signup is limited to those offers that provide appropriate environmental benefits, as determined by CCC, or that would otherwise rank highly under § 1410.31(b) and may include high priority practices including, but not limited to, filter strips, riparian buffers, shelterbelts, field windbreaks, living snowfences, grass waterways, shallow water areas for wildlife, salt-tolerant vegetation, prairie strips, field borders, and practices to benefit certain approved wetlands and public wellhead protection areas.(c) Notwithstanding paragraph (a) or (b) of this section, offers to enroll acreage specified in § 1410.6(d) may be submitted only during signup periods as announced by CCC. At least 1 ranking period will be announced subsequent to the announcement of offers specified in paragraph (a) of this section. Eligible offers will be evaluated and ranked as provided in § 1410.31(e) and (f) .