Nitrogen rate, density, and plant architecture jointly determine lodging risk in drip fertigated spring maize

High-density planting has significantly boosted maize yields in Xinjiang China. However, excessive nitrogen application under such conditions has intensified stem lodging risks, revealing inconsistencies between conventional nitrogen fertilization theories and practical production outcomes. Field experiments were conducted in irrigated maize-growing regions of arid and semi-arid region Xinjiang China using subsurface drip irrigation and staged fertilization. Two maize varieties, DH618 and XY335, were cultivated at planting densities of 7.5 × 10 4 plants ha −1 and 12.0 × 10 4 plants ha −1 . Nitrogen application levels ranged from 0 to 720 kg ha −1 across nine treatments. Increasing nitrogen application significantly elevated stem breaking rate. The stem breaking rate correlated with key factors such as fracture resistance, plant morphology, puncture strength, and dry weight per unit length. Feature importance analysis using a Random Forest model quantified the contribution of each variable to lodging prediction. The results identified dry matter/stem breaking force (DM/SBF) as the most influential factor, Eight parameters—including dry weight/stalk breaking force, leaf area/stalk breaking force, ear height, ear coefficient, stalk breaking force, plant height, center of gravity height, moment of force—accounted for over 75.7 % of the predictive power of the stem breaking model, underscoring their significance in determining lodging susceptibility. Higher nitrogen input increases ear height, dry matter accumulation, and leaf area, thereby raising the center of gravity and wind-exposed surface area of maize plants. These changes reduce stem breaking resistance under wind stress, increasing lodging risk. While nitrogen application promotes maize growth and yield, its potential negative effects on stem stability warrant careful consideration.