Adaptive fertilization strategies for premature senescence challenges in film-mulched maize: Insights from a 4-year field study

In semi-arid regions, film mulching enhances maize yield but often causes premature senescence resulting from increased soil temperatures and late-stage water and nutrient deficiencies, compromising yield potential. How fertilization management to alleviate these effects under various mulching methods remains insufficiently studied, particularly in long-term field studies. To address these issues, an in-situ four-year field experiment (2014–2017) was conducted in northwest China, evaluating five fertilization rates (N: 0–285 kg ha −1 ; P 2 O 5 : 0–143 kg ha −1 ) under two typical film mulching planting methods (full film mulching, RFF; half film mulching, RFH). The results showed that compared with RFH, RFF increased soil temperature by 1.2°C and grain yields by 21.8–43.9 %, but caused more serve plant premature senescence, ultimately limiting maize yield stability and potential, especially at low fertilization rates. Fertilization effectively improved leaf nutritional and photosynthetic characteristics, prolonged the growth period, and increased grain yields by 103.5–160.7 % under RFF (reaching 7355.0–8715.8 kg ha −1 ) and 94.0–160.7 % (reaching 5362.3–6871.3 kg ha −1 ) under RFH. However, increasing fertilization rates progressively aggravated secondary drought related to dry-wet alternation under RFF, reducing soil water content during 70–130 days after sowing from 15.6 % (without fertilization) to 12.3–13.5 % (with fertilization), whereas it was from 15.6 % to 12.9–13.8 % under RFH. Path analysis revealed that yield improvements were primarily driven by increased soil temperature and fertilization-enhanced water and nutrient uptake, which jointly enhancing leaf photosynthetic capacity. Although mulching-induced shortening of the growth period partially limited yield potential, this effect was secondary. This study provides insights that for film-mulched maize in semi-arid regions, moderately decreasing fertilization rates with increasing mulch ratios (RFF: N 157.6 + P₂O₅ 78.8 kg ha⁻¹ vs. RFH: N 201.2 + P₂O₅ 100.6 kg ha⁻¹) serve as adaptive strategies to address premature senescence challenges. • Premature canopy senescence caused by film mulching constrains maize yield potential. • Fertilization alleviated mulching-induced premature senescence. • Fertilization may cause secondary drought under full film mulching. • Full film mulching may require lower fertilization rate than half film mulching.