Planting date significantly affects Missouri rice productivity

Rice ( Oryza sativa L.) planting dates have trended earlier in the upper Mid‐Southern United States, including Missouri, due to desire for earlier harvest. Earlier harvests lead to greater potential for dry harvest conditions, which facilitates fall field preparation and the ability to plant next year's crop timelier. Another benefit of planting early has been greater yield potential. Planting date trials were conducted from 2022 to 2024 at the Missouri Rice Research Farm near Malden, MO, and in 2023 near Portageville, MO, to determine the effect of planting date on rice production. Thirteen cultivars, including both hybrids and inbred varieties, were grown at all four sites under direct‐seeded, delayed‐flood culture. Planting dates were spaced approximately 3 weeks apart and included mid‐March, early April, late April, mid‐May, and early June. Data indicated that, generally, planting earlier resulted in higher grain yield potential. For all cultivars evaluated, seeding rice in mid‐May or early June decreased grain yield by up to 23% and 34%, respectively, relative to seeding rice in mid‐March. Total rice and head rice yield were unaffected by planting date except for the June planting, which produced a lower total rice yield for all cultivars and a lower head rice yield for two of the 13 cultivars. Planting earlier resulted in a greater number of days to heading, as less heat was accumulated in March and early April compared to later dates. These results suggest that rice should be planted in Southeast Missouri between mid‐March and early May, as rice yield trended downward after the late April planting window.