Oilseed rape straw returning changes soil reducibility and affects the root and yield of rice in the rape‐rice rotation field at Sichuan Basin area of China.

To elucidate the influence of rape straw returning on soil reducibility and to understand its effects on rice growth and yield in rape‐rice rotation system, 3 years field experiment with 8 treatments of straw incorporation carried out at Mianyang Sichuan Province of China. Results showed that the lowest RCEh value founded at 14–18 d after rice planting; With the increasing of rape straw incorporation, the amount of root (number, weight and length) and root bleeding intensity both increased significantly during 27–32 d after rice planting; 0–20 d are the fast decomposing period of rape straw in rice field. At 10–22 d after rice planting, there is negative correlation between rice root growth and soil reducibility and a negative correlation between rice root and straw incorporation. Oil seed rape straw returning into soil, either by mulching or by ploughing, make the soil more reducible with lower Eh and higher content of reducing material, Fe2+ and hinder the growth of rice root with lower amount (length, weight and number) and bleeding density during this period. Comparing with other straw returning methods, straw returning by ploughing method with the rape straw of 3.0 t/hm2 is more suitable in rice‐rape rotation farms where is convenient for mechanical operation. [ABSTRACT FROM AUTHOR]