Abstract:Rice straw returning to the field is an effective way to improve fertility and increase yield. However, the large amount of straw, low water content during harvesting and the difficulty in chopping and scattering all have a negative effects on straw returning, moreover reduce the quality of tillage and transplanting operations in the northeast rice area. It is urgent to investigate a suitable straw returning pattern, improve the quality of straw returning and tillage operations and support the application of rice straw returning technology in the northeast rice area. Aiming to solve these problems, a two-year straw returning experiment was carried out in Qixing Farm in Heilongjiang Province. Four treatments were taken into consideration, including CK (no straw returning, autumn plowing + spring puddling), returning treatment 1 (straw returning, autumn plowing + spring puddling), returning treatment 2 (straw returning, autumn plowing, autumn rotary + spring leveling), and returning treatment 3 (straw returning, autumn rotation buried + spring leveling). Matching equipment was selected for the different patterns and the effects of straw returning and tilling were measured. The two-year experiment showed that all the three straw returning patterns could realize the full amount straw returning, and conditions of soil surface after straw returning could meet the requirement of rice transplanting, in other words it could ensure the quality of rice transplanting and greening up. It could be concluded that returning treatment 3 had a better performance, which meant that it could achieve better surface flatness, slurry degree and vegetation coverage. Two-year experiment results showed that compared with returning treatment 1, treatment 2 did not significantly improve the soil conditions before rice transplanting, although rotation was added in autumn and leveling replaced stirring in spring.