A special demonstration showing improved returns of rice straw to the crop fields, organized by the Institute of Agricultural Resources and Regional Planning (IARRP), CAAS, was successfully held recently in Tailai county, Qiqihar city, China's Northeast Heilongjiang province. Over 100 participants attended the event, called the On-Site Observation, Yield Measurement, and Seminar on autumn water-logged press-bury straw incorporation. These included academicians of the Chinese Academy of Engineering (CAE), such as Zhang Jiabao from the Institute of Soil Science, Chinese Academy of Sciences, and Wang Lichun from the Jilin Academy of Agricultural Sciences, along with experts from the national rice industry technology system, agricultural departments of Heilongjiang province, and major farm producers from various provinces and cities.

Returning straw to the field is a highly effective soil enrichment practice. However, the northeastern region of China faces significant challenges in fully incorporating rice straw into the fields. Traditional methods such as shallow rotary tillage and deep ploughinging are costly and ineffective in decomposing straw, which affects seedling growth and is not well-accepted by farmers. Addressing this issue is widely regarded as being crucial for China's food security and black soil conservation. To tackle this challenge, Liu Hongbin, a researcher at the IARRP, led a team that developed a scientific principle of water-heat-biology synergy to promote decomposition and eliminate obstacles. They innovated a technique of autumn water-logged press-bury straw incorporation, proposing a new approach: Shifting from spring to autumn incorporation, from dry to wet preparation, from rotary tillage to cutting and burying, and from partial to full straw returns. They also developed integrated agricultural machinery that combines deep rotary tillage, vertical cutting, pressing and leveling operations. 

In the rice trial demonstration fields at Alaxin village, Daxing town, in Tailai county, seven experts from the Chinese Society of Agro-Ecological Environment Protection measured yields — using the autumn water-logged press-bury straw incorporation technique. Results showed that fields using the technique achieved a yield of 634.9 kg per mu, 76.7 kg more than fields using the partial spring rotary straw returns, representing a 13.7% increase.

CAE academician Zhang Jiabao from the Institute of Soil Science praised the aautumn water-logged press-bury straw incorporation technology. Zhang said it was great for solving the problem of rice straw returns in northeastern region of China and noted that the supporting integrated machinery effectively reduced costs and increased efficiency, addressing both straw burning in spring and black soil conservation. CAE academician Wang Lichun from the Jilin Academy of Agricultural Science highlighted the fact that this technique allowed for the effective use of thermal resources during the fallow season, overcoming issues related to low spring temperatures and slow decomposition that could affect rice growth and tillering. The accompanying machinery efficiently buried straw, reducing labor and time. He said that the demonstration and promotion of this technology was expected to play a positive role in protecting black soil and increasing rice yields. 

Currently, the adaptability of the autumn water-logged press-bury straw incorporation technique has been validated under various regional and climatic conditions in Northeast China. From 2023 to 2026, continuous yield measurements taken over four years showed that the autumn water-logged press-bury straw incorporation treatment increased yields by more than 10% compared to partial spring rotary treatments. Additionally, the application of the technology has increased the thickness of the plow layer by over 5 cm, organic carbon by more than 12%, and reduced nitrogen and phosphorus losses by over 20% — achieving a synergistic enhancement of rice yields and black soil fertility.