Evaluating the Adaptability and Sustainability of Different Straw Incorporation Strategies in Northeastern China: Impacts on Rice Yield Formation, Nitrogen Use Efficiency, and Temporal Soil Nutrient Dynamics

Straw incorporation effectively improves soil fertility and crop yield, and its adaptation to single-season rice production in cold temperate regions is a current research focus. This study conducted a two-year continuous in situ field experiment with four treatments: no straw incorporation (CK), straw incorporation with autumn rotary tillage (SC), straw incorporation with autumn plowing (SH), and straw incorporation with spring rotary tillage (ST). This study investigated the effects of straw incorporation on rice growth and the soil environment to understand the soil-crop interactions and their impact on rice yield. The results indicate that in the single-season rice production system of Northeast China, straw incorporation reduces the number of tillers, dry matter accumulation, and leaf area index in the early rice growth stage but promotes dry matter accumulation in the later stages. Straw incorporation over two consecutive years increased the rice yield by 2.07%, with the SC treatments showing optimal performance. This increased yield could lead to higher economic returns for the farmers. Additionally, straw incorporation potentially increases the total nitrogen and soil organic matter (SOM) content in the topsoil, thus providing environmental benefits by reducing the need for synthetic fertilizers. Factor analysis reveals that the SC treatments enhances dry matter accumulation by influencing soil nutrient levels in the later rice growth stages, thereby improving rice yield and nitrogen recovery efficiency. By altering soil nutrient availability at different growth stages, different straw incorporation regimes regulate the material production strategy of rice and the ‘source-sink’ relationship. This research provides a theoretical basis for enhancing soil fertility and rice yield in cold temperate regions through improved straw management strategies. These findings support policy initiatives that promote large-scale straw incorporation in commercial rice production for its potential economic and environmental benefits.