Abstract:In order to reveal the effects of micro-nano aerated irrigation on rice growth under straw returning condition in wheat-rice rotation area and put forward the optimal aerated irrigation method, rice pot experiments were conducted and six experiment treatments were set up, i.e., no straw returning with no aeration irrigation treatment (CK), wheat straw returning with no aeration irrigation treatment (ST), wheat straw returning with 0.3L/min air intake micro-nano aerated irrigation treatment (SO1), wheat straw returning with 0.5L/min air intake micro-nano aerated irrigation treatment (SO2), wheat straw returning with 0.7L/min air intake micro-nano aerated irrigation treatment (SO3), and wheat straw returning with 0.9L/min air intake micro-nano aerated irrigation treatment (SO4). The soil reduction characteristics and rice growth under different treatments were observed. Results showed that straw returning could enhance the soil reducibility significantly. Micro-nano aerated irrigation could improve the soil reducibility, and the improvement effect would be enhanced gradually with the increase of air intake volume. When the air intake volume was 0.9L/min, the contents of soil reductive organic matter, Fe2+ and Mn2+ could be reduced by 48.66%, 56.11% and 42.76%, respectively. Aerated irrigation with an air intake of 0.5~0.7L/min could promote the growth and development of rice, alleviate the problem of the rice growth inhibition in the early stage caused by straw returning, and promote the growth of rice roots, which was conducive to rice photosynthesis, promoting the accumulation of dry matter, and thereby increasing the rice yield. The highest yield improvement could be reached 19.7% after aerated irrigation. Considering the effect of micro-nano aerated irrigation on soil reducibility and rice growth, micro-nano bubble water with dissolved oxygen concentration of 8.06mg/L (SO3 treatment) was recommended to irrigate rice under straw returning conditions in wheat-rice rotation areas.