Abstract

Rice (Oryza sativa L.) ratooning is the production of a second rice crop from the stubble left after the main crop harvest. Its growth and development are affected by the environment factors and the growth condition of the main crop. The objectives of this study were to evaluate the effects of different cultivations (DS: direct-seeding, ST: seedling-throwing, TP: transplanting) and planting periods of the main crop on physiological traits and rice yields, as well as to find the source of the nutrients in the ratoon crop by studying the stubble dry matter and nitrogen translocation of pre-anthesis and its efficiency in the ratoon crop. The yields of the main crop were different significantly. The yield of TP was significantly higher than ST and DS as well as the yield of D3 was more than the yields of other periods. In the ratoon crop, the yield of D1 was more than that in other periods. The ratooning ability was different significantly among different cultivations. The cultivations affected the tillering ability in the ratoon crop and the translocation of the stubble dry matter and nitrogen uptaking in which TP was better than others. From March to April, sowing or transplanting date did not affect the stubble dry matter and N translocation of pre-anthesis and its efficiency. The results suggested that TP treatment could get the highest yield among the three cultivations. The crops could get higher grain yield when the ratoon rice were planted during the period of late March to April in southeastern China.

Key words: Direct-seeding, seedling-throwing, transplanting, ratoon rice, grain yield.