Abstract: In 2020, field trials were conducted in Datonghu District in Hunan province according to the split zone design, using rice varieties Taiyou390 and Hyou518 as materials, with conventional machine transplanting (T1), manual seedling throwing (T2) and orderly mechanical seedling-broadcasting (T3), to determine the seedling quality, yield and yield composition, stem dynamics and growth period under different planting methods, and to explore the influence of different planting methods on the growth and development characteristics, grain yield and yield components of the late season rice under the influence of autumn low temperature(ALT). Find out planting methods that have more stable yield and disaster reduction effects under the influence of ALT, and explore their disaster reduction mechanisms to provide a theoretical basis for rice production and disaster prevention and reduction strategies. The results showed that: (1) the seedling quality of the orderly mechanical seedling-broadcasting planting model cultivated by the pot seedling raising technology was significantly better than that of the blanket seedling raising technology. (2) The orderly mechanical seedling-broadcasting model obsessed the highest growth recovery and tillering speed than other models. (3) The orderly mechanical seedling-broadcasting shortened the growth duration of rice, which was reduced by 4−12d and 3−8d, respectively for Taiyou390 and Hyou518 as compared with other models. (4) Under ALT, the panicle-tiller rate, grain filling percentage, harvest index, panicle number, grain weight and grain yield of rice was improved under orderly mechanical seedling-broadcasting model. When compared with T1 and T2, the grain yield under orderly mechanical seedling-broadcasting was increased by 21.7% and 273.5% for Taiyou390, and was increased by 12.9% and 19.6% for Hyou518, respectively. In summary, the orderly mechanical seedling-broadcasting pronouncedly enhanced the performance of late season rice regarding seedling quality, growth recovery and early tillering speed, panicle numbers, grain filling percentage, grain weight and grain yield especially under ALT. The present study demonstrated that the orderly mechanical seedling-broadcasting is a safety rice mechanical production method to guarantee the safe production of late season rice under severely chilling stress.

Key words: Seedling quality, Growth period, Orderly mechanical seedling-broadcasting, Yield, Autumn low temperature (ALT)