Straw returning and nitrogen reduction: Strategies for sustainable maize production in the dryland.

Implementing continue straw returning practices and optimizing nitrogen application can mitigate nitrogen losses and enhance nitrogen use efficiency (NUE) in dryland. 15N-labeled technique offers a robust approach for tracking fertilizer nitrogen fate and assessing nitrogen use efficiency. Based on the continue (>6 yr) experiment, we conducted a two-year experiment (2020 and 2021) to evaluate the effects of straw returning and nitrogen management under plastic film mulching on 15N recovery rates, N 2 O emissions and maize yield with three treatments: no straw returning with 225 kg N·ha−1 under plastic film mulching (RP-N 225), straw returning with 225 kg N·ha−1 under plastic film mulching (RPS-N 225), and straw returning with 20% nitrogen reduction (180 kg N·ha−1) under plastic film mulching (RPS-N 180). After six years, both continue straw returning with plastic film mulching increased uptake of fertilizer nitrogen, had higher 15N recovery rates than RP-N 225 , leading to increased 15N accumulation in grain and aboveground biomass, ultimately enhancing yield. The RPS-N 225 treatment exhibited the highest spring maize yield and nitrogen harvest index. The RPS-N 180 treatment significantly increased maize yield more than RP-N 225 and had the highest NUE, partial factor productivity of nitrogen fertilizer, and nitrogen uptake efficiency, with improvements ranging from 1.7 to 2.4%, 19.3–29.6%, and 17.3–27.5%, respectively, compared to the other treatments. Moreover, RPS-N 225 resulted in significantly higher cumulative N 2 O emissions and yield-scaled N 2 O emissions than the other treatments, whereas the RPS-N 180 treatment significantly decreased yield-scaled N 2 O emissions compared to RP-N 225. Hence, combining continue straw returning with appropriate nitrogen reduction can effectively increase maize yield and yield-scaled N 2 O emissions. By offering insights into optimizing nitrogen fertilizer management after continue maize straw return, this study is contributed to widespread adoption of straw return practices and sustainable agricultural development in semi-arid areas. • Continue straw returning with film mulching increased uptake of fertilizer nitrogen and grain yield. • RPS-N 180 demonstrated highest 15N recovery rate, NUE, and NupE in three treatments. • RPS-N 180 achieved a higher grain yield than RP-N 225 , albeit lower than RPS-N 225. • RPS-N 225 increased yield-scaled N 2 O emissions, RPS-N 180 decreased compared to RP-N 225. • Continue straw returning partially replaces inorganic fertilizers while sustained high grain yield. [ABSTRACT FROM AUTHOR]