Objective Excessive phosphorus (P) fertilizer application in the black soil region of Northeast China has led to low P use efficiency in recent decades. This study examines the effects of optimized fertilization combined with P application frequency on spring maize yield, fertilizer use efficiency, and soil P balance, providing theoretical support for improving P resource utilization and cost-effectiveness in maize-producing areas of Northeast China.

Methods A six-year field experiment (2018−2023) with two-experiment-cycle design was conducted in Gongzhuling, Jilin Province, a major maize-producing region. Under a recommended P application rate of 100 kg P₂O₅ ha⁻¹, four treatments were implemented: P0 (no P fertilizer), P1 (one P fertilizer application event every three years), P2 (two P fertilizer application events every three years), and P3 (P applied annually). Following each maize harvest, plant and tilled-layer soil samples were collected annually to determine maize biomass, P uptake, and soil Olsen P content. These measurements were used to investigate changes in maize yield, P use efficiency, and apparent P balance across different phosphorus application frequencies.

Results Compared to the P3 treatment, the P1 treatment significantly reduced maize yield and P uptake, while the P2 treatment showed no significant yield and P uptake difference across years. The P2 treatment achieved a P recovery efficiency (REP) of 25.1 percentage points, agronomic efficiency (AEP) of 20.5 kg/kg, and partial factor productivity (PFPP) of 172.7 kg/kg, which were 4.9 percentage points, 6.2 kg/kg, and 56.9 kg/kg higher than the P3 treatment, respectively. The P2 treatment also demonstrated higher P physiological use efficiency, increasing by 16.4 kg/kg and 3.5 kg/kg compared to the P1 and P3 treatments, respectively. Long-term P deficiency led to a significant decrease followed by stabilization in soil Olsen P content, with an average annual decrease of 5.7 mg/kg during the experimental period. In years without P application, the soil Olsen P content in the P1 and P2 treatments was lower than in the P3 treatment. However, it recovered rapidly upon resuming P application, showing no significant difference from P3 treatment. Throughout the experimental cycle, the P1 and P2 treatments resulted in soil phosphorus deficits, with mean annual apparent P₂O₅ deficits of 36.3 and 6.4 kg ha⁻¹, respectively. In contrast, the P3 treatment maintained a phosphorus surplus, exhibiting a mean annual apparent surplus of 23.6 kg ha⁻¹. Phosphorus application frequency significantly influenced the apparent balance of soil nitrogen (N) and potassium (K). Specifically, the apparent N balance was in surplus, near balance, and in slight deficit for the P1, P2, and P3 treatments, respectively. K balances were deficient across all treatments, with mean annual K₂O deficits of 51.9, 65.3, and 66.2 kg ha⁻¹ for P1, P2, and P3, respectively, attributable to straw removal. Additionally, the P2 treatment effectively maintained N and K uptake and nutrient balance, showing no significant difference compared to the P3 treatment.

Conclusion In the continuous maize cropping system of Central and southern Jilin, one P fertilizer application event every three years reduces maize yields and depletes soil P, significantly lowering soil Olsen P content. However, there is no significant difference between two P fertilizer application events every three years and P applied annually in terms of maize yield, P uptake and the soil Olsen P content, which not only improves the P fertilizer utilization rate, but also greatly reduces the soil P surplus, and maintain basic N and P apparent balances. Under current soil P levels and recommended P application rates, reducing P fertilizer application by one year within a three-year period offers a viable strategy for optimizing P use and enhancing P resource efficiency in maize production in the black soil region of Central and southern Jilin.