Inter-row stubble seeding and plant growth regulators to improve field pea standability and production

Abstract

Field pea (Pisum sativum) is an important economic and rotational crop in Alberta, Canada; however, standability problems are a major barrier to increasing seeded area in highly productive growing environments. Field experiments were conducted from 2015 to 2017 at three sites in the central and Peace regions of Alberta to determine if (i) pea standability and production can be improved using inter-row seeding into untilled standing wheat stubble; (ii) pea standability and production can be improved using chlormequat chloride (CCC), trinexapac-ethyl (TXP), or ethephon (ETH) plant growth regulators (PGRs); and (iii) PGR responses are cultivar-specific. Depending on the site–year, there were 16–17 inter-row seeding, PGR, and cultivar treatment combinations arranged in a randomized complete block design. Relative to the no-stubble control, inter-row seeding into 20- or 30-cm-tall, untilled wheat stubble significantly improved standability between 6% and 23% under conditions when lodging occurred. It also reduced days to maturity and increased 1000-seed weight, but had no effect on yield. Individual PGR treatments (CCC, TXP, and ETH) generally had small and inconsistent impacts on agronomic traits, yield, and seed quality. In dry conditions, PGRs reduced yield. CDC Meadow was slightly more responsive to PGR treatments than AAC Lacombe, indicating responses may be cultivar-specific. Because of the small and inconsistent responses, PGRs have little value as an agronomic tool in field pea. Alternatively, inter-row seeding into standing wheat stubble is a low-cost, easy to implement practice for improving field pea standability.