Agronomic and Physiological Responses of Field-Grown Gladiolus (Gladiolus × hybridus L.) to Subsurface Drip and Pressurized Pulse Injection Irrigation

Moisture deficit is a primary limiting factor in field floriculture, necessitating the adoption of highly efficient irrigation strategies. This three-year field study (2019–2021) evaluated the impact of surface drip, subsurface drip (SDI), and a prototype pulse injection irrigation system against a non-irrigated control on the biometry, corm yield, and mineral profile of Gladiolus × hybridus. Subsurface drip (SDI) and surface drip irrigation provided the most favorable and stable agronomic outcomes, particularly for daughter corm yield and quality. Conversely, pulse injection irrigation showed a highly nuanced response; while it significantly increased generative spike length by 68.5% under severe late-season drought in 2021, it failed to improve overall daughter corm mass and significantly increased plant lodging (15–20%). This performance is hypothesized to stem from localized soil structural disturbance and mechanical stress on the shallow, fibrous root system under high-pressure water delivery (4 bar). Furthermore, chemical analyses revealed that irrigation increased leaf calcium accumulation while simultaneously causing a dilution of nitrogen, phosphorus, and potassium due to increased biomass. In conclusion, SDI is highly recommended for professional gladiolus production to stabilize root-zone moisture and ensure superior commercial quality of both aerial and underground organs, while pressurized pulse injection requires further pressure-nozzle optimization to mitigate physical crop disturbance.