Optimizing nitrogen management cooperates yield stability and environmental nitrogen balance from the perspective of continuous straw incorporation

Context

The rational allocation of straw and nitrogen (N) fertilizer resources is a crucial strategy for enhancing grain yield and addressing global food security.

Research question

To determine the yield stability and environmental impacts of long-term straw incorporation and N management.

Methods

An eight-year field experiment was conducted in Northeast China to compare varying N levels (0, 112, 187, 262, and 337 kg ha⁻¹) under rotary-till and plough-till combined straw turnovers (RTS and PTS).

Results

Yield and its stability, dry matter accumulation, N uptake, and apparent N balance (ANB) increased with increasing N levels up to 262 kg ha⁻¹, but the related N use efficiency declined due to N application. The optimal thresholds for N application were 172–254 and 147–200 kg ha⁻¹ under RTS and PTS, respectively, which provided 93.0 %–99.9 % and 92.2 %–97.5 % of the maximum production potential while facilitating soil N sequestration and ANB. Additionally, PTS outperformed RTS in grain yield (3.5 %), sustainable index of yield (8.2 %), dry matter accumulation (6.5 %), N uptake (4.7 %), and N uptake efficiency (1.9 %).

Conclusions

Straw incorporation with an optimal N threshold (172–200 kg N ha⁻¹) is advantageous for achieving long-term stable production and reducing the environmental impact on maize farmland.

Significance

This study highlights the importance of regulating N fertilizer regulation in the context of straw amendment and proposes an optimal threshold for N application.