Optimizing nitrogen, phosphorus, and potassium fertilization regimes to improve maize productivity under double ridge-furrow planting with full film mulching

In semi-arid regions of northwest China, the planting pattern of double ridge-furrow with full film mulching (DRFM) is widely used to improve maize productivity. However, little is known about reasonable application amounts of nitrogen (N), phosphorus (P), and potassium (K) fertilizers for maize under this planting pattern, and local farmers applying unreasonably large fertilizer amounts results in wasted resources and environmental pollution. Therefore, the effects of N, P, and K fertilizer application amounts on the leaf area index (LAI), aboveground dry matter accumulation and translocation, grain yield and water productivity (WP), and nutrient uptake and utilization by maize under DRFM were studied in 2018 and 2019. A field experiment was conducted with five fertilization levels under DRFM, and the treatments of which were: M1: 60 kg N ha–1, 60 kg P2O5 ha–1, 45 kg K2O ha–1; M2–5 each increased N, P2O5, and K2O by 60 kg ha–1, 30 kg ha–1 and 45 kg ha–1, respectively, compared to the previous treatment. No fertilizer under flat planting with non-film mulching was included as the control. The results showed that the logistic model better described the dynamic accumulation process for aboveground dry matter. The LAI, maximum aboveground dry matter accumulation rate, average accumulation rate for aboveground dry matter, and N, P, and K uptake initially increased, but then declined as fertilizer applications increased, and all factors reached their maximum values under M3. Dry matter translocation and accumulation after silking were positively correlated with grain yield. Grain yield and WP were greatest under M3 with an average of 10.77 t ha–1 and 29.12 kg m–3 across the two years, which were 4.46–138.19% and 1.29–153.15% greater than the other treatments, respectively. Although N, P, and K fertilizer use efficiency was lower under M3 than M1 and M2, it produced a much higher yield and WP. In summary, 180 kg N ha–1, 120 kg P2O5 ha–1, and 135 kg K2O ha–1 is recommended as the optimal N, P, and K fertilizer application scheme for maize under DRFM to achieve the great yield, and water and fertilizer use efficiencies in northwest China.